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"THE STATE OF THE 6.8" ... JULY, 2009 (Page 3 of 8)
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Originally Posted By Rocketman:
Originally Posted By m4hk33:
i love the 6.8 concept but until ammunition becomes as availble and affordable as surplus 762x51 or 556 im having a hard time jumping on board even with all the benifits. even with the SSA plinking ammo that is comming out somtime. you can still shoot twice the amount 556 and slghtly more 762. i would rather be able to train my ass of with a 3x more 556 then switch just yet to 6.8 IMHO you don't have to "switch over" just buy a 6.8 upper. Train, plink or whatever with your 5.56 and use the 6.8 only where and when you want. I don't hunt much but when I do I take the 6.8SPC. Last time my boys and I went hog hunting we killed 4 hogs with 5 rounds. Even counting the rounds we used to get things sighted in we spent very little on ammo. My household zombie killer is loaded with combat SSA 115 gr OTM 6.8 rounds. Sure they are expensive but so is TAP in 5.56 and if it wasn't 6.8 that's what I'd have in my weapon anyway. I won't give the 5.56 up completely as long as 1) it still performs well with modern loads, and is even a pretty decent performer with M193 at close ranges, and 2) some good ammo is available at good prices - M193 at $0.34 per round (PRVI, when you can find it - I'm stocked up  ) or PRVI Match at less than $0.45 per round.
Here's the problem, and where the 6.8 really shines: -For defense, combat, or SHTF, price isn't an issue - the few magazines worth of ammo one would use (at most) in any realistically imagineable situation will NOT break the bank, and good 6.8 loads are available at prices no higher than premium 5.56 or .223 loads, with better performance. -For hunting, it's not even close. The 6.8 basically carries a bullet 50% larger than equivalent 5.56 loads. I've nevr shot a deer with a 5.56 - call me inexperienced if you will, but there is a REASON I've never shot a deer with aa 5.56 - it's just too small to be reliable unless shot conditions are perfect. I've killed dozens (way beyond 100) of deer in my life, and witnessed many, many more being shot, and I've seen very few shot under 'perfect' conditions. I simply can't in good conscience use a 5.56 on deer. Having said that, when the 6.8 came out, I had to have one to hunt with - and after 5 dead deer at ranges from 25 to 305 yards, I'm convinced that the 6.8 is big enough for close range (inside 300 yards, where virtually ALL of my hunting happens) deer hunting. I'm not sure exactly where the line is between 'not enough' and 'enough', but for deer, the 5.56 is awfully close to the former, the 6.8 is definitely within the latter. My biggest regret of 6.8 ownership is that I didn't buy every box of the hornady v-max load I could afford when it was ~12 per box. 
For what I do with my ARs, I don't need all of them to be 6.8s, but for the record, I wish I had 2 more 6.8s and 2 less 5.56s in my safe. One of my next ARs (I have two planned in my mind, hopefully) will be another 6.8. 
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...But his word was in mine heart as a burning fire shut up in my bones, and I was weary with forbearing, and I could not stay...All my familiars watched for my halting...But the LORD is with me as a mighty terrible one...
Jeremiah 20 9-11
Jeremiah 20 9-11
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For all the guys who say "6.8 is too expensive" I have 2 answers for you:
1. Learn to pick up your brass and re-load. I am reloading 6.8 for about $6 a box with my brass using PREMIUM bullets such as Sierra Match Kings, Hornady V-Max, Hornady BTHP, and Sierra Pro Hunters 2. Even better yet-learn to pick up your once fired brass and SELL it for .25-.30 each on the boards. This way you are re-couping $6 of each box. When Silver State comes out with their $13 a box "plinking" load this summer buy a bunch and sell the once fired brass and you are shooting for $7 a box great ammo from a great company that is 100% American made, and not supporting any third world nations selling us steel cased crap for what brass was a year ago. Just my .10 my .02 is free 
BTW I bought one of those "sub standard" 1/10 CMMG SAAMI spec uppers in 2006 (that shoots MOA for $450 for the upper) and recently reamed it to SPCII so I am good to go. I love the round and wish I had more time to shoot it |
AR Variants Mod and Juris Doctor (in training)!
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Originally Posted By m4hk33:
i love the 6.8 concept but until ammunition becomes as availble and affordable as surplus 762x51 or 556 im having a hard time jumping on board even with all the benifits. even with the SSA plinking ammo that is comming out somtime. you can still shoot twice the amount 556 and slghtly more 762. i would rather be able to train my ass of with a 3x more 556 then switch just yet to 6.8 Unless your Mil/LEO, FACT is no one is "training their ass" off with ammo prices where they are for 223/5.56 and 762NATO, plus lack of ammo across the board AND small rifle and pistol primers are like gold now... this info comes first hand from some well known trainers in my area (Eric Lund etc). Now if you have some ridiculous stash from the 1990's era, then you can train your ass off, but knowing ARFCOMMERS, well... yeah. |
When there's lead in the air... there's hope in the heart.
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Oh, how the ghost of you clings...
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Oh, how the ghost of you clings...
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Originally Posted By Cold:
Originally Posted By m4hk33:
i love the 6.8 concept but until ammunition becomes as availble and affordable as surplus 762x51 or 556 im having a hard time jumping on board even with all the benifits. even with the SSA plinking ammo that is comming out somtime. you can still shoot twice the amount 556 and slghtly more 762. i would rather be able to train my ass of with a 3x more 556 then switch just yet to 6.8 Unless your Mil/LEO, FACT is no one is "training their ass" off with ammo prices where they are for 223/5.56 and 762NATO, plus lack of ammo across the board AND small rifle and pistol primers are like gold now... this info comes first hand from some well known trainers in my area (Eric Lund etc). Now if you have some ridiculous stash from the 1990's era, then you can train your ass off, but knowing ARFCOMMERS, well... yeah. 70s and 80s actually 
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The truth, is the truth.. even if no one believes it..
and a lie.. is a lie...even if everyone believes it
and a lie.. is a lie...even if everyone believes it
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Originally Posted By BullittBoy:
For all the guys who say "6.8 is too expensive" I have 2 answers for you: 1. Learn to pick up your brass and re-load. I am reloading 6.8 for about $6 a box with my brass using PREMIUM bullets such as Sierra Match Kings, Hornady V-Max, Hornady BTHP, and Sierra Pro Hunters 2. Even better yet-learn to pick up your once fired brass and SELL it for .25-.30 each on the boards. This way you are re-couping $6 of each box. When Silver State comes out with their $13 a box "plinking" load this summer buy a bunch and sell the once fired brass and you are shooting for $7 a box great ammo from a great company that is 100% American made, and not supporting any third world nations selling us steel cased crap for what brass was a year ago. This is right. Problem for me is it's another thing to do to support my habit - with kids, a business, etc. I would rather rely on factory ammo - but today’s prices is making that very difficult. Question: Are you hunting for primers the same way others are hunting for ammo? If the primers are just as hard to find as .40 at Walmart then it's another fly in the ointment... |
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edit, keep political and off color comments and accusations OUT OF TECH~ Cold |
"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
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Originally Posted By crenca:
Originally Posted By hi-tech-rancher:
Excuse me,....who are you?....Please do all of us a favor and either contribute in a technical manner, or GTFO of the thread. I am someone who thinks you overstate your case - your technical case. In particular, I think you downplay the spec issues. Your a promoter who has put personal resources at 'solving' these issues. Good for you, I and others benefit. However you over sell. Forums like this are for information and discussion. You do yourself or 6.8 no favors by trying to bully people from seeing these issues. edit, keep political and off color comments and accusations OUT OF TECH~ Cold[/img] This is a technical discussion, not a pissing contest. Please do not get this thread locked. If you have nothing to contribute then go to GD. [img]http://www.ar15.com/images/smilies/smiley_confused.gif[/img] There has been a lot of progress made in the last few years. Those of us that own 6.8's are pleased with these updates and write ups. Please keep up your awesome research and share with us. [img]http://www.ar15.com/images/smilies/icon_smile_dead.gif[/img] |
AR Variants Mod and Juris Doctor (in training)!
Joined:
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Posts:
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IF YOU CANNOT STAY ON TOPIC AND REFRAIN FROM YOUR OWN PERSONAL PISSING MATCH OR AXE TO GRIND MORE WARNINGS WILL BE SENT. You can disagree, but keep political accusations and other NEEDLESS IMPLICATIONS RELATED TO THAT OUT OF TECH, BY POSTING HERE YOU SHOULD HAVE READ THE CODE OF CONDUCT AT THE TOP, NO EXCUSES.
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When there's lead in the air... there's hope in the heart.
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Oh, how the ghost of you clings...
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Oh, how the ghost of you clings...
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Primers can be found, I got 1,000 CCI #41's last week here in Houston for .03 each, you just have to look. To be honest, I cannot find H322 in Houston right now, I need some more powder soon. That was something I have never seen "scarce", I remember the primer issues in early 90's, but not powder.
This cartridge is what sparked my interest again in re-loading. I had not done it in a long time. If you are diligent I go with a friend and we load about 200 rounds in a half a day on a single stage. Ahem, and then we drink beer and tell the wives it took all day
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Thank you, Cold. And thanks to all of you that are making meaningful contributions to this thread. I would really like to see it stay up and running, simply because I am getting so many questions from so many of you via IM and phone conversations, which indicate to me that more of the manufacturers are indeed wanting to change their specs.
If you have a certain rifle that you want, and it is in the "second group" of barrel makers (those who don't now offer a SPC II or DMR chamber) it might be a good idea just to let them know that you are interested in their product, but only when it has these specs. Market forces will drive a change in their product faster than just about anything else. I looked over the Ruger piston gun recently. It is SAAMI, 1 in 10 twist....shame....the piston looks nice, but I hope those of you considering one will let them know you would like to see them make it in SPC II, 11 twist, 4 groove. They are listening, I can assure you. |
"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
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Originally Posted By hi-tech-rancher:
If you have a certain rifle that you want, and it is in the "second group" of barrel makers (those who don't now offer a SPC II or DMR chamber) it might be a good idea just to let them know that you are interested in their product, but only when it has these specs. Market forces will drive a change in their product faster than just about anything else. I looked over the Ruger piston gun recently. It is SAAMI, 1 in 10 twist....shame....the piston looks nice, but I hope those of you considering one will let them know you would like to see them make it in SPC II, 11 twist, 4 groove. They are listening, I can assure you. I agree. I'm one of those rare birds who has a spec-I chamber and is happy with it (WOA barrel), but I wouldn't buy another spec-I barrel, and manufacturers need to know this. |
...But his word was in mine heart as a burning fire shut up in my bones, and I was weary with forbearing, and I could not stay...All my familiars watched for my halting...But the LORD is with me as a mighty terrible one...
Jeremiah 20 9-11
Jeremiah 20 9-11
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Originally Posted By BullittBoy:
Primers can be found, I got 1,000 CCI #41's last week here in Houston for .03 each, you just have to look. +1 on the primers coming back around I ordered 5K of #41's from Grafs and Sons on 6/3 and they shipped out last Monday. |
The ONLY "Common Sense Laws" that we need is the one that requires our Representative's to use it.
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Originally Posted By hi-tech-rancher:
I looked over the Ruger piston gun recently. It is SAAMI, 1 in 10 twist....shame....the piston looks nice, but I hope those of you considering one will let them know you would like to see them make it in SPC II, 11 twist, 4 groove. They are listening, I can assure you. As you know my dad has a 6.8 mini. When I was testing 110 gr TTSX loads I shot my 11 twist spc II AR15 next to his mini and there was only a slight sign of more pressure so maybe they have loose barrels. Also I did run 25 tubbs bullets through it. I did back off max loads though. He hardly shoots over 100-200 yards as he is 88 so with 110 gr TSX or 85 gr TSX it will do anything he needs it to. Got a pig with it not too long ago. Have not tried any factory SSA 85 gr tsx loads though it, but I think they would shoot fine. |
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While there are undoubtedly some 1 in 10 twist barrels whcih will shoot hotter 6.8 X 43mm SPC loads, the combination of SAAMI chamber and 10 twist is just too much like shooting 5.56 in a .223 for people to chance.
That is the crux of the matter here. If we could just get manufacturers to stop saying, "yeah, we admit there is NO advantage to using a 150 grain bullet-compatible twist (for the .270 Winchester!) in the 6.8, but....but, ours still shoots everything else OK...we think." We would al be a lot better off. If ANYONE can explain to me why they need to make their 6.8 rifle with a 1 in 10" twist, given that the bullets we use are between 80 and 115 grains, then please do it here. I want to know why you feel that fast a twist is necessary and why you chose it. Especially, when all the laws of ballistics say that for the lightest bullets in a given caliber's range, you would always tend to use the slowest twist that will still stabilize the most commonly used bullets. In all our testing, even the 1 in 12" twist stabilized up to the 130 grain bullets. Why would you want to go to any faster a twist rate? I have never heard a valid reason. Please somebeody give me one. 
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"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
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Originally Posted By tammons:
I would guess that the reason ruger makes their mini 6.8 with a 1:10 twist is because their other 270 winchester rifles are also 1:10 twist so those are the blanks they use. Going Hog hunting tomorrow for a week. Yep. that's the reason we have heard from many. Of course, the .270 Winchester does not, and never has used bullets in the 80-115 grain range. Rather, it needed a twist to stabilize 130-160 grain bullets. Its been a few years now, but I hope that barrel manufacturers are starting to understand that the 6.8 X 43 mm SPC is not the .270 Winchester, and therefore they cannot simply extrapolate the twist rates for the bullets just like they can't extrapolate the .270 Win. chamber for its case. |
"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
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Its probably that leftover adage, IE some buyer might want to shoot heavy bullets.
Smae problem with the 30RAR. That gun needs a 16 twist. I bought a box 20 Federal premium 270 winchester rounds for a friend where I hunt loaded with 110 gr TTSX bullets. 3600 fps !. Yikes With shipping they were so expensive, I could have bought dies and 50 bullets and brass for the same amount. Those are real hog whackers though. I will send an email suggestion to Ruger. |
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Originally Posted By hi-tech-rancher:
While there are undoubtedly some 1 in 10 twist barrels whcih will shoot hotter 6.8 X 43mm SPC loads, the combination of SAAMI chamber and 10 twist is just too much like shooting 5.56 in a .223 for people to chance. That is the crux of the matter here. If we could just get manufacturers to stop saying, "yeah, we admit there is NO advantage to using a 150 grain bullet-compatible twist (for the .270 Winchester!) in the 6.8, but....but, ours still shoots everything else OK...we think." We would al be a lot better off. If ANYONE can explain to me why they need to make their 6.8 rifle with a 1 in 10" twist, given that the bullets we use are between 80 and 115 grains, then please do it here. I want to know why you feel that fast a twist is necessary and why you chose it. Especially, when all the laws of ballistics say that for the lightest bullets in a given caliber's range, you would always tend to use the slowest twist that will still stabilize the most commonly used bullets. In all our testing, even the 1 in 12" twist stabilized up to the 130 grain bullets. Why would you want to go to any faster a twist rate? I have never heard a valid reason. Please somebeody give me one. I'll tell you why I ended up with two SPC II 1:10 twist bbls......there was NO CHOICE. I voiced the opinion that both LWRC (6 groove) and Robinson Armament's XCR 6.8 (4 groove) should both be 1:11. But both of my 6.8s so far are for SBRs.....so I justified the lack of options with the fact that the bbls are 10.5" and 11" trying to convince myself that the shorter bbls needed the faster twist. Of course, I don't really buy that....but since the mfgs aren't giving us what we want....we're pretty much at their mercy with regards to fancy piston ARs or the XCR. Supposedly, RA is on it's way to a 1:11 twist 4 groove bbl....and when it's available, I'm getting one for my 16 or 18.6" build. Until then, I'll have to live with the faster twist in the shorter bbls. I'm pretty sure I won't have overpressure signs with commonly available commercial ammo, but it sure would be nice to have more options.....as I've told both mfgs. Personally, I'd love to see at least a 1:11 bbl from both mfgs.....but I won't hold my breath.
Sean |
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Originally Posted By SeanK1ng:
Originally Posted By hi-tech-rancher:
While there are undoubtedly some 1 in 10 twist barrels whcih will shoot hotter 6.8 X 43mm SPC loads, the combination of SAAMI chamber and 10 twist is just too much like shooting 5.56 in a .223 for people to chance. That is the crux of the matter here. If we could just get manufacturers to stop saying, "yeah, we admit there is NO advantage to using a 150 grain bullet-compatible twist (for the .270 Winchester!) in the 6.8, but....but, ours still shoots everything else OK...we think." We would al be a lot better off. If ANYONE can explain to me why they need to make their 6.8 rifle with a 1 in 10" twist, given that the bullets we use are between 80 and 115 grains, then please do it here. I want to know why you feel that fast a twist is necessary and why you chose it. Especially, when all the laws of ballistics say that for the lightest bullets in a given caliber's range, you would always tend to use the slowest twist that will still stabilize the most commonly used bullets. In all our testing, even the 1 in 12" twist stabilized up to the 130 grain bullets. Why would you want to go to any faster a twist rate? I have never heard a valid reason. Please somebeody give me one. I'll tell you why I ended up with two SPC II 1:10 twist bbls......there was NO CHOICE. I voiced the opinion that both LWRC (6 groove) and Robinson Armament's XCR 6.8 (4 groove) should both be 1:11. But both of my 6.8s so far are for SBRs.....so I justified the lack of options with the fact that the bbls are 10.5" and 11" trying to convince myself that the shorter bbls needed the faster twist. Of course, I don't really buy that....but since the mfgs aren't giving us what we want....we're pretty much at their mercy with regards to fancy piston ARs or the XCR. Supposedly, RA is on it's way to a 1:11 twist 4 groove bbl....and when it's available, I'm getting one for my 16 or 18.6" build. Until then, I'll have to live with the faster twist in the shorter bbls. I'm pretty sure I won't have overpressure signs with commonly available commercial ammo, but it sure would be nice to have more options.....as I've told both mfgs. Personally, I'd love to see at least a 1:11 bbl from both mfgs.....but I won't hold my breath.
Sean I totally understand you plight. Thus, our desire to get the right info out there. Another note about twist. The twist itself does not necessarily dictate a barrel's propensity to "cause" pressure problems. However, when you shoot lighter, high velocity bullets in very fast twists, the bullet tends to skid along the first few turns of the lands before it catches, and that tears the jacket up. It also erodes throats faster. Why is this a good thing? Um,....it isn't. However, for the sake of clarity let me do this. Here are the factors that affect pressure the most to the least, in my opinion, in general terms, as it regards this cartridge: 1) the powder charge and bullet weight 2) the chamber specs 3) the bore ratio....i.e lands to grooves. Depth, width and number of lands. 4) Rifling Style, i,e poly, 6 groove, etc. 5) twist rate. *6) The presence / absence of Chrome lining. This has an asterisk, because if the bore is properly relieved to allow for it, and it is done right, it does not affect pressure significantly. If it is applied too thick, you all know what can happen.
As you can see twist is near the last in line. If all the other factors were causative of way too much pressure, the right twist could never ameliorate the problem. OTOH, if the twist is WAY too fast, we know that it tends to cause problems like destroying jackets on bullets spun too severely for their length, density, jacket thickness, and weight. All factors are additive. Therefore, if you have a hot round fired in a SAAMI chamber, 6 groove (with high lands) , 1 in 10" twist , chrome lined barrel with a production grade bore (meaning it is not perfectly smooth or cylindrical throughout) , and you are shooting full sized, 277 projectiles....... you get the picture. |
"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
|
Originally Posted By SeanK1ng:
But both of my 6.8s so far are for SBRs.....so I justified the lack of options with the fact that the bbls are 10.5" and 11" trying to convince myself that the shorter bbls needed the faster twist. Of course, I don't really buy that.... ... Personally, I'd love to see at least a 1:11 bbl from both mfgs.....but I won't hold my breath.
Sean How do both SBRs perform on paper at 500, 600, 700 yards? Only reason I'm asking is to see if you know at what maximum range both barrels' required spin drops off and rounds start key-holing... Then, repeat the test on any new 11 twist from them. Your buy-in may be proved running such a test. |
"A man with one AR is like a man with one arm." -me (pun intended)
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I voiced the opinion that both LWRC (6 groove) and Robinson Armament's XCR 6.8 (4 groove) should both be 1:11....
But both of my 6.8s so far are for SBRs.....so I justified the lack of options with the fact that the bbls are 10.5" and 11" trying to convince myself that the shorter bbls needed the faster twist. Of course, I don't really buy that....but since the mfgs aren't giving us what we want....we're pretty much at their mercy with regards to fancy piston ARs or the XCR. Supposedly, RA is on it's way to a 1:11 twist 4 groove bbl....and when it's available, I'm getting one for my 16 or 18.6" build. Until then, I'll have to live with the faster twist in the shorter bbls. I'm pretty sure I won't have overpressure signs with commonly available commercial ammo, but it sure would be nice to have more options.....as I've told both mfgs. Personally, I'd love to see at least a 1:11 bbl from both mfgs.....but I won't hold my breath.
Sean I don't have any discernable pressure signs from my XCR using SSA "tactical" loads. They are the highest pressure factory load (I think I have tried all available except the Remington core lokt) as I can turn my gas setting down to 2 and they still get thrown as far or farther than most other factory ammo on 3 (with BVAC, even 4). I wonder if the spec II in combo with the 4 grove barrel more than makes up for the 1:10 twist. Have not tried any hot hand loads however... |
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Originally Posted By anr6t:
Originally Posted By hi-tech-rancher:
Please somebeody give me one. "Because we already tooled up to make 1:10 barrels and its expensive to get a new mandrel" 
Actually not true at all!! I contacted a few barrel manufacturers and asked them what it would take to make a 1/11.5 twist which I consider probably the optimum twist rate. They all said that it was not any more problem than the usual 1/10 twist rate. Mike Rock makes LMT barrels and all he needs is LMT to change the specs for their barrels and it is a done deal!! ARE YOU LISTENING LMT!!!!!!!!!!!!!!!!!! The chamber corrections are just as easy if not easier!!!!!!!!!! The difference between SAAMI and Spec II is a leade of 0.050" vs 0.100"!!! Those are the ONLY spec changes needed to bring the chamber into Spec II. The DMR and DMR-C (the 'C' stands for chrome lining before anyone asks) are a little different in that the angle of the throat to bore of 30 in the DMR series and 45 in the SAMMI and Spec II, also the leade length is I believe 0.085". Noveske calls their chamber MOD 1 which is essentially the Spec II because of the 0.100" leade/freebore. All LMT has to do is change their chambers to 0.100", and make the next order from Mike Rock 5R 1/11.5 twist and the world's problems will cease to exist!!!
ARE YOU LISTENING LMT!!!!!!!!!!!!!!!!!!!!!!!!!! Have a nice day!!!
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God Bless and good shootin'!!!
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Originally Posted By chris65:
Originally Posted By SeanK1ng:
But both of my 6.8s so far are for SBRs.....so I justified the lack of options with the fact that the bbls are 10.5" and 11" trying to convince myself that the shorter bbls needed the faster twist. Of course, I don't really buy that.... ... Personally, I'd love to see at least a 1:11 bbl from both mfgs.....but I won't hold my breath.
Sean How do both SBRs perform on paper at 500, 600, 700 yards? Only reason I'm asking is to see if you know at what maximum range both barrels' required spin drops off and rounds start key-holing... Then, repeat the test on any new 11 twist from them. Your buy-in may be proved running such a test. I've never shot any 10.5" bbl past 300 yards (and I VERY rarely do that). I can hit a man sized target, but I'm running 4moa T-1s on both rifles. I'm not shooting that short of a bbl for groups, so it's hard to say. Sorry. Sean |
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Originally Posted By hi-tech-rancher:
Originally Posted By SeanK1ng:
Originally Posted By hi-tech-rancher:
While there are undoubtedly some 1 in 10 twist barrels whcih will shoot hotter 6.8 X 43mm SPC loads, the combination of SAAMI chamber and 10 twist is just too much like shooting 5.56 in a .223 for people to chance. That is the crux of the matter here. If we could just get manufacturers to stop saying, "yeah, we admit there is NO advantage to using a 150 grain bullet-compatible twist (for the .270 Winchester!) in the 6.8, but....but, ours still shoots everything else OK...we think." We would al be a lot better off. If ANYONE can explain to me why they need to make their 6.8 rifle with a 1 in 10" twist, given that the bullets we use are between 80 and 115 grains, then please do it here. I want to know why you feel that fast a twist is necessary and why you chose it. Especially, when all the laws of ballistics say that for the lightest bullets in a given caliber's range, you would always tend to use the slowest twist that will still stabilize the most commonly used bullets. In all our testing, even the 1 in 12" twist stabilized up to the 130 grain bullets. Why would you want to go to any faster a twist rate? I have never heard a valid reason. Please somebeody give me one. I'll tell you why I ended up with two SPC II 1:10 twist bbls......there was NO CHOICE. I voiced the opinion that both LWRC (6 groove) and Robinson Armament's XCR 6.8 (4 groove) should both be 1:11. But both of my 6.8s so far are for SBRs.....so I justified the lack of options with the fact that the bbls are 10.5" and 11" trying to convince myself that the shorter bbls needed the faster twist. Of course, I don't really buy that....but since the mfgs aren't giving us what we want....we're pretty much at their mercy with regards to fancy piston ARs or the XCR. Supposedly, RA is on it's way to a 1:11 twist 4 groove bbl....and when it's available, I'm getting one for my 16 or 18.6" build. Until then, I'll have to live with the faster twist in the shorter bbls. I'm pretty sure I won't have overpressure signs with commonly available commercial ammo, but it sure would be nice to have more options.....as I've told both mfgs. Personally, I'd love to see at least a 1:11 bbl from both mfgs.....but I won't hold my breath.
Sean I totally understand you plight. Thus, our desire to get the right info out there. Another note about twist. The twist itself does not necessarily dictate a barrel's propensity to "cause" pressure problems. However, when you shoot lighter, high velocity bullets in very fast twists, the bullet tends to skid along the first few turns of the lands before it catches, and that tears the jacket up. It also erodes throats faster. Why is this a good thing? Um,....it isn't. While I agree that a 1-11 or so would be optimal, honestly, I am NOT worried about 1-10" twists. Guys, take a page from the 5.56 playbook - 80% of the ammo I shoot is 55 grain, but all my 5.56 AR's are 1-7" twist, an even more extreme 'mismatch' than the 6.8 situation, and there are no accuracy oor pressure problems as a result. People with 5.56 ARs have been proving the relative unimportance of perfect rates of twist ever since 1-7" twists came out. Again, yes, it's best if the optimum twist is used, but it's not the end of the world if it isn't. |
...But his word was in mine heart as a burning fire shut up in my bones, and I was weary with forbearing, and I could not stay...All my familiars watched for my halting...But the LORD is with me as a mighty terrible one...
Jeremiah 20 9-11
Jeremiah 20 9-11
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Originally Posted By arowneragain:
Originally Posted By hi-tech-rancher:
Originally Posted By SeanK1ng:
Originally Posted By hi-tech-rancher:
While there are undoubtedly some 1 in 10 twist barrels whcih will shoot hotter 6.8 X 43mm SPC loads, the combination of SAAMI chamber and 10 twist is just too much like shooting 5.56 in a .223 for people to chance. That is the crux of the matter here. If we could just get manufacturers to stop saying, "yeah, we admit there is NO advantage to using a 150 grain bullet-compatible twist (for the .270 Winchester!) in the 6.8, but....but, ours still shoots everything else OK...we think." We would al be a lot better off. If ANYONE can explain to me why they need to make their 6.8 rifle with a 1 in 10" twist, given that the bullets we use are between 80 and 115 grains, then please do it here. I want to know why you feel that fast a twist is necessary and why you chose it. Especially, when all the laws of ballistics say that for the lightest bullets in a given caliber's range, you would always tend to use the slowest twist that will still stabilize the most commonly used bullets. In all our testing, even the 1 in 12" twist stabilized up to the 130 grain bullets. Why would you want to go to any faster a twist rate? I have never heard a valid reason. Please somebeody give me one. I'll tell you why I ended up with two SPC II 1:10 twist bbls......there was NO CHOICE. I voiced the opinion that both LWRC (6 groove) and Robinson Armament's XCR 6.8 (4 groove) should both be 1:11. But both of my 6.8s so far are for SBRs.....so I justified the lack of options with the fact that the bbls are 10.5" and 11" trying to convince myself that the shorter bbls needed the faster twist. Of course, I don't really buy that....but since the mfgs aren't giving us what we want....we're pretty much at their mercy with regards to fancy piston ARs or the XCR. Supposedly, RA is on it's way to a 1:11 twist 4 groove bbl....and when it's available, I'm getting one for my 16 or 18.6" build. Until then, I'll have to live with the faster twist in the shorter bbls. I'm pretty sure I won't have overpressure signs with commonly available commercial ammo, but it sure would be nice to have more options.....as I've told both mfgs. Personally, I'd love to see at least a 1:11 bbl from both mfgs.....but I won't hold my breath.
Sean I totally understand you plight. Thus, our desire to get the right info out there. Another note about twist. The twist itself does not necessarily dictate a barrel's propensity to "cause" pressure problems. However, when you shoot lighter, high velocity bullets in very fast twists, the bullet tends to skid along the first few turns of the lands before it catches, and that tears the jacket up. It also erodes throats faster. Why is this a good thing? Um,....it isn't. While I agree that a 1-11 or so would be optimal, honestly, I am NOT worried about 1-10" twists. Guys, take a page from the 5.56 playbook - 80% of the ammo I shoot is 55 grain, but all my 5.56 AR's are 1-7" twist, an even more extreme 'mismatch' than the 6.8 situation, and there are no accuracy oor pressure problems as a result. People with 5.56 ARs have been proving the relative unimportance of perfect rates of twist ever since 1-7" twists came out. Again, yes, it's best if the optimum twist is used, but it's not the end of the world if it isn't. Which is exactly why we focused on the chambers predominantly, for now, so as to pick the low hanging fruit. All we want right now is for manufacturers change their chamber specs to either SPC II or DMR, even if they use the somewhat ridiculous 1:10 twist. It just takes a few turns of a reamer for goodness sake 
For the record, I do not own a single 1:7 twist 5.56 rifle. Why? 1) because I think the 6.8 kicks the 5.56's ass so badly that I don't have much need for that caliber any more......especially not the compromised version where a bullet, much heavier than that for which the rifle was designed, is "needed" to increase its lethality. This is exactly why the Mil is looking for something with which to replace it. It seems that 1:7 twist and MK262 did not fix all ills after all. 2) because if I need to shoot a 77 grain projectile at something, why wouldn't I just upgrade to an 85 grain bullet going 400+ FPS faster?? Sorry, I know its blasphemy, but I have no use for 77 grain SMK's in a 1:7 twist .224 rifle, especially when you consider they cost the same as 6.8 SPC rounds. 3) because the 5.56 does what it does best, via the velocity it achieves. Take away its velocity, and you have a .22 LR with pointy bullets. If the velocity is low enough, even good bullets with excellent construction are castrated and can no longer deform or frag as they were designed, renderning them as poor as other calibers which are far less capable. I tend to favor the 1:12 twist in the 5.56 rifles I have. The 14.5" Colt lightweight shoots a 40 grain VMax at 3500 FPS, and does some pretty nasty things to small varmints coyotes, etc. The 20" shoots that bullet at 3750.....  Faster means flatter, too. Trajectory is improved with the twist that this rifle was designed for. I still consider the 1:7 twist for the 5.56 a bastardization.
I don't know, call me a Maverick...... I guess. 
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"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
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Originally Posted By mrnuke7175:
Too bad there is suck little production for 6.8 ammo. At the price of roughly $1 a shot most people can't afford to properly train with it. That is about to change very soon. When SSA gets their new powder in, they will release a new plinkiing / training round which should cost around $14 per box. The only reason we don't have it now, is because of the ridiculous hoarding of ammo, by so many people that don't even shoot it. When they finally get it and load the ammo, look for millions of rounds to hit the market. The last projection was that it would be middle or end of July. Why do you think I posted this now? The last thing I want to see is a bunch of weak, lame 6.8 Remington SPC ammo on the market, because there are still so many SAAMI chambers out there, when instead we could be getting 6.8 X 43 mm loaded 100 grain accubonds at 3000 FPS from a 20" barrel, and the 85 grain TSX at 3150 from a 16" barrel. It is coming. Just be patient.
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"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
|
Originally Posted By arowneragain:
Originally Posted By hi-tech-rancher:
Originally Posted By SeanK1ng:
Originally Posted By hi-tech-rancher:
While there are undoubtedly some 1 in 10 twist barrels whcih will shoot hotter 6.8 X 43mm SPC loads, the combination of SAAMI chamber and 10 twist is just too much like shooting 5.56 in a .223 for people to chance. That is the crux of the matter here. If we could just get manufacturers to stop saying, "yeah, we admit there is NO advantage to using a 150 grain bullet-compatible twist (for the .270 Winchester!) in the 6.8, but....but, ours still shoots everything else OK...we think." We would al be a lot better off. If ANYONE can explain to me why they need to make their 6.8 rifle with a 1 in 10" twist, given that the bullets we use are between 80 and 115 grains, then please do it here. I want to know why you feel that fast a twist is necessary and why you chose it. Especially, when all the laws of ballistics say that for the lightest bullets in a given caliber's range, you would always tend to use the slowest twist that will still stabilize the most commonly used bullets. In all our testing, even the 1 in 12" twist stabilized up to the 130 grain bullets. Why would you want to go to any faster a twist rate? I have never heard a valid reason. Please somebeody give me one. I'll tell you why I ended up with two SPC II 1:10 twist bbls......there was NO CHOICE. I voiced the opinion that both LWRC (6 groove) and Robinson Armament's XCR 6.8 (4 groove) should both be 1:11. But both of my 6.8s so far are for SBRs.....so I justified the lack of options with the fact that the bbls are 10.5" and 11" trying to convince myself that the shorter bbls needed the faster twist. Of course, I don't really buy that....but since the mfgs aren't giving us what we want....we're pretty much at their mercy with regards to fancy piston ARs or the XCR. Supposedly, RA is on it's way to a 1:11 twist 4 groove bbl....and when it's available, I'm getting one for my 16 or 18.6" build. Until then, I'll have to live with the faster twist in the shorter bbls. I'm pretty sure I won't have overpressure signs with commonly available commercial ammo, but it sure would be nice to have more options.....as I've told both mfgs. Personally, I'd love to see at least a 1:11 bbl from both mfgs.....but I won't hold my breath.
Sean I totally understand you plight. Thus, our desire to get the right info out there. Another note about twist. The twist itself does not necessarily dictate a barrel's propensity to "cause" pressure problems. However, when you shoot lighter, high velocity bullets in very fast twists, the bullet tends to skid along the first few turns of the lands before it catches, and that tears the jacket up. It also erodes throats faster. Why is this a good thing? Um,....it isn't. While I agree that a 1-11 or so would be optimal, honestly, I am NOT worried about 1-10" twists. Guys, take a page from the 5.56 playbook - 80% of the ammo I shoot is 55 grain, but all my 5.56 AR's are 1-7" twist, an even more extreme 'mismatch' than the 6.8 situation, and there are no accuracy oor pressure problems as a result. People with 5.56 ARs have been proving the relative unimportance of perfect rates of twist ever since 1-7" twists came out. Again, yes, it's best if the optimum twist is used, but it's not the end of the world if it isn't. forward from Constructor People change calibers in order to get an extra 100 fps, The difference between a standard and a magnum is sometimes only 200fps. A 10 twist can be 100 fps slower than a 12 twist due to maximum load usable, just the rifling design can make 100 fps difference with the exact same load. We are telling everyone how to get the most performance from the 6.8, If you don't mind shooting slow loads you can shoot what ever you want. Generalized statements regarding calibers aren't always true, what works with one does not always work with all of them, that is why there are different burn rates for powders. Some are more efficient than others due to the case capacity to bore area ratio. The 30BR is known to be one of the most efficient cartridges in the world, the 6.8 is more efficient. |
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When Size Matters 6.8 SPC
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When Size Matters 6.8 SPC
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Originally Posted By hi-tech-rancher:
Originally Posted By mrnuke7175:
Too bad there is suck little production for 6.8 ammo. At the price of roughly $1 a shot most people can't afford to properly train with it. That is about to change very soon. When SSA gets their new powder in, they will release a new plinkiing / training round which should cost around $14 per box. The only reason we don't have it now, is because of the ridiculous hoarding of ammo, by so many people that don't even shoot it. When they finally get it and load the ammo, look for millions of rounds to hit the market. The last projection was that it would be middle or end of July. Why do you think I posted this now? The last thing I want to see is a bunch of weak, lame 6.8 Remington SPC ammo on the market, because there are still so many SAAMI chambers out there, when instead we could be getting 6.8 X 43 mm loaded 100 grain accubonds at 3000 FPS from a 20" barrel, and the 85 grain TSX at 3150 from a 16" barrel. It is coming. Just be patient. Hmm.. That's not that bad. I was thinking of getting a .308 AR based weapon, mayeb I'll get a 6.8 upper instead. I can always train more with the 5.56 upper anyways I guess and keep the 6.8 on for handywork. |
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Originally Posted By mrnuke7175:
Originally Posted By hi-tech-rancher:
Originally Posted By mrnuke7175:
Too bad there is suck little production for 6.8 ammo. At the price of roughly $1 a shot most people can't afford to properly train with it. That is about to change very soon. When SSA gets their new powder in, they will release a new plinkiing / training round which should cost around $14 per box. The only reason we don't have it now, is because of the ridiculous hoarding of ammo, by so many people that don't even shoot it. When they finally get it and load the ammo, look for millions of rounds to hit the market. The last projection was that it would be middle or end of July. Why do you think I posted this now? The last thing I want to see is a bunch of weak, lame 6.8 Remington SPC ammo on the market, because there are still so many SAAMI chambers out there, when instead we could be getting 6.8 X 43 mm loaded 100 grain accubonds at 3000 FPS from a 20" barrel, and the 85 grain TSX at 3150 from a 16" barrel. It is coming. Just be patient. Hmm.. That's not that bad. I was thinking of getting a .308 AR based weapon, mayeb I'll get a 6.8 upper instead. I can always train more with the 5.56 upper anyways I guess and keep the 6.8 on for handywork. I can't say much more, but I am 100% certain that the 6.8 X 43 mm SPC ammo market will improve....for buyers, soon. It would be wise to have some of you sheckles saved. 
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"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
|
Originally Posted By hi-tech-rancher:
Which is exactly why we focused on the chambers predominantly, for now, so as to pick the low hanging fruit. All we want right now is for manufacturers change their chamber specs to either SPC II or DMR, even if they use the somewhat ridiculous 1:10 twist. It just takes a few turns of a reamer for goodness sake
For the record, I do not own a single 1:7 twist 5.56 rifle. Why? 1) because I think the 6.8 kicks the 5.56's ass so badly that I don't have much need for that caliber any more......especially not the compromised version where a bullet, much heavier than that for which the rifle was designed, is "needed" to increase its lethality. This is exactly why the Mil is looking for something with which to replace it. It seems that 1:7 twist and MK262 did not fix all ills after all. 2) because if I need to shoot a 77 grain projectile at something, why wouldn't I just upgrade to an 85 grain bullet going 400+ FPS faster?? Sorry, I know its blasphemy, but I have no use for 77 grain SMK's in a 1:7 twist .224 rifle, especially when you consider they cost the same as 6.8 SPC rounds. 3) because the 5.56 does what it does best, via the velocity it achieves. Take away its velocity, and you have a .22 LR with pointy bullets. If the velocity is low enough, even good bullets with excellent construction are castrated and can no longer deform or frag as they were designed, renderning them as poor as other calibers which are far less capable. I tend to favor the 1:12 twist in the 5.56 rifles I have. The 14.5" Colt lightweight shoots a 40 grain VMax at 3500 FPS, and does some pretty nasty things to small varmints coyotes, etc. The 20" shoots that bullet at 3750..... Faster means flatter, too. Trajectory is improved with the twist that this rifle was designed for. I still consider the 1:7 twist for the 5.56 a bastardization.
I don't know, call me a Maverick...... I guess.
If I remember right, the only reason the military orginally used 7 twist is to stabilize that long tracer bullet. 7 twist is not needed for more normal use. |
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Originally Posted By AR-10man:
Originally Posted By hi-tech-rancher:
Which is exactly why we focused on the chambers predominantly, for now, so as to pick the low hanging fruit. All we want right now is for manufacturers change their chamber specs to either SPC II or DMR, even if they use the somewhat ridiculous 1:10 twist. It just takes a few turns of a reamer for goodness sake
For the record, I do not own a single 1:7 twist 5.56 rifle. Why? 1) because I think the 6.8 kicks the 5.56's ass so badly that I don't have much need for that caliber any more......especially not the compromised version where a bullet, much heavier than that for which the rifle was designed, is "needed" to increase its lethality. This is exactly why the Mil is looking for something with which to replace it. It seems that 1:7 twist and MK262 did not fix all ills after all. 2) because if I need to shoot a 77 grain projectile at something, why wouldn't I just upgrade to an 85 grain bullet going 400+ FPS faster?? Sorry, I know its blasphemy, but I have no use for 77 grain SMK's in a 1:7 twist .224 rifle, especially when you consider they cost the same as 6.8 SPC rounds. 3) because the 5.56 does what it does best, via the velocity it achieves. Take away its velocity, and you have a .22 LR with pointy bullets. If the velocity is low enough, even good bullets with excellent construction are castrated and can no longer deform or frag as they were designed, renderning them as poor as other calibers which are far less capable. I tend to favor the 1:12 twist in the 5.56 rifles I have. The 14.5" Colt lightweight shoots a 40 grain VMax at 3500 FPS, and does some pretty nasty things to small varmints coyotes, etc. The 20" shoots that bullet at 3750..... Faster means flatter, too. Trajectory is improved with the twist that this rifle was designed for. I still consider the 1:7 twist for the 5.56 a bastardization.
I don't know, call me a Maverick...... I guess.
If I remember right, the only reason the military orginally used 7 twist is to stabilize that long tracer bullet. 7 twist is not needed for more normal use. I think you are right. But consider this: If that was the reason. Why are all of today's rifles being so configured? 1) This allows for heavy weight bullets to be fired. Why is there a need for such outlandishly heavy bullets for the .223 / 5.56? What is wrong with the original .223? 2) This also allows for the lighter projectiles( 55 grains) , more commonly in use, to still be fired, while allowing heavy projos as well. 3) this does make things difficult if the user wants to fire the lightest for caliber bullets. 4) Heavier projos are necessary to make the 5.56 more lethal ? Doesn't that mean we compromise velocity badly? Why not just get a bigger cartridge instead? 5) changing the twist to allow much heavier bullets dictates that the shooter now has to contend with a much longer and usually heavier barrel, to assure proper performance. Now, we have just negated handling ergonomics in urban environments, and offset all that weight advantage everyone carps about with the tiny little 5.56 bullets. So, we took something that was never designed for the mosaic it is today, and changed the twist to something quite strange, put very heavy bullets in it, cut its velocity badly and forced people to carry longer barrels so as to fire the bullets fast enough to maintain some level of performance and called it "improved" 
Anyone still wonder why the 5th SFG / AMU wanted an intermediate cartridge that could be fired from a 14.5" barrel and still generate good velocity? So: 77 grain SMK at 2650 from a 16 inch barrel....ho hum OR...85 grain TSX from a 16" barrel at 3150......Oh yeah. |
"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
i want 6.8 badly, but many on this forum made a good point to me. in a SHTF situation 5.56 is going to be more available than 6.8 unless the military or lots more people adopt it. i'll take a .223 with 500 rounds over a 6.8 with 50, especially knowing you are more likely to find .223 . i'm really glad to see that prices are supposed to drop on 6.8, but it will still always be cheaper to train with .223 . i plan to really get into my 6.8 when i get the upper, but my bcm middy that i just bought and at least 500 nato rounds will always be near by. here's to having the best of both worlds!
now all i need is a 7.62x39 upper. that would be a hot threesome! 
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Originally Posted By s3neo:
i want 6.8 badly, but many on this forum made a good point to me. in a SHTF situation 5.56 is going to be more available than 6.8 unless the military or lots more people adopt it. i'll take a .223 with 500 rounds over a 6.8 with 50, especially knowing you are more likely to find .223 . i'm really glad to see that prices are supposed to drop on 6.8, but it will still always be cheaper to train with .223 . i plan to really get into my 6.8 when i get the upper, but my bcm middy that i just bought and at least 500 nato rounds will always be near by. here's to having the best of both worlds!
now all i need is a 7.62x39 upper. that would be a hot threesome! The original SHTF scenario that any ammo will be available really doesn't hold water. Just look at the last election and the run on ammo and that wasn't even a true SHTF..... If you talk to people that went through Katrina in New Orleans and the surrounding area, ammo wasn't there either. The realistic only way anyone will get ammo is taking it from people, not what you can scrounge. Like HTR said earlier, wait and get the plinking ammo from SSA and reloading supplies and you will be good to go.
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God Bless and good shootin'!!!
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Originally Posted By Cohibra45:
Originally Posted By s3neo:
i want 6.8 badly, but many on this forum made a good point to me. in a SHTF situation 5.56 is going to be more available than 6.8 unless the military or lots more people adopt it. i'll take a .223 with 500 rounds over a 6.8 with 50, especially knowing you are more likely to find .223 . i'm really glad to see that prices are supposed to drop on 6.8, but it will still always be cheaper to train with .223 . i plan to really get into my 6.8 when i get the upper, but my bcm middy that i just bought and at least 500 nato rounds will always be near by. here's to having the best of both worlds!
now all i need is a 7.62x39 upper. that would be a hot threesome! The original SHTF scenario that any ammo will be available really doesn't hold water. Just look at the last election and the run on ammo and that wasn't even a true SHTF..... If you talk to people that went through Katrina in New Orleans and the surrounding area, ammo wasn't there either. The realistic only way anyone will get ammo is taking it from people, not what you can scrounge. Like HTR said earlier, wait and get the plinking ammo from SSA and reloading supplies and you will be good to go.
Not only that, but the likelihood that you will survive firefights where you are burning through thousands of rounds is HIGHLY unlikely. You'll want to keep a very low profile if SHTF. As someone said in the survival forum (to paraphrase....they said it better than I can remember): "If you're planning to scrounge your ammo for SHTF, you're already fucked." You should have a decent stockpile on hand. JMO, Sean |
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Thanks for the info, I am very glad I am going with an Addax GPU Upper with the new chamber!
Hope your right about ammo. What powders have shown the most promise with the new chamber and 1/11 twist? I'm going to try and load some 110vmax or 85TSX. PRI still the best mag for reloaders? |
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Check out the 68 forums for more detailed reloading info, but stealing from others postings and knowledge:
H4198 is good for <100gr bullets H332 good for >100gr H335, Reloader 7, Reloader 10x - Decent performers (X-Terminator: useable, but not optimum) There are other powders, but these are the ones I remember specifically. When looking at the load data, be sure to take into account your chamber and twist! SAAMI chambers and tight twists may put you at dangerous pressures!! |
Italian poet Dante Alighieri:
"The hottest places in Hell are reserved for those who, in times of great moral crisis, maintain their neutrality."
"The hottest places in Hell are reserved for those who, in times of great moral crisis, maintain their neutrality."
| Just a quick question for you 68 gurus! I am looking at buying a new upper in 6.8 from rock river. Rock River is on the list of ''Good \ New chambers'' but if you look at there website it still shows a SAAMI spec?? Any ideas? Thanks in advance for any halp you can provide! |
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Originally Posted By SuperD1982:
Just a quick question for you 68 gurus! I am looking at buying a new upper in 6.8 from rock river. Rock River is on the list of ''Good \ New chambers'' but if you look at there website it still shows a SAAMI spec?? Any ideas? Thanks in advance for any halp you can provide! Their website lists 6.8 Rem SPC - SAAMI II as the chamber, which is the improved chamber... |
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Originally Posted By superman007:
Thanks for the info, I am very glad I am going with an Addax GPU Upper with the new chamber! Hope your right about ammo. What powders have shown the most promise with the new chamber and 1/11 twist? I'm going to try and load some 110vmax or 85TSX. PRI still the best mag for reloaders? After much trial and error, here are the most basic needs for a 6.8 reloader: RE 7, great for the lightrer bullets like the 85 TSX, and the 90 grain Speer TNT. Achieves good velocity H322, great for the 110 grain SPH, and also works with the VMax reasonably well. Tolerates compression and meters in powders drop well. RE10X, great for the Nosler Accubond, and the 110 Barnes TTSX. Achieves good velocity but not quite as tolerant of compression, so may tend to run just a little hot near max. H4198 versatile with the 85 TSX, but also may be used for the 110 TSX, 90 grain TNT, 100 grain Hornady, and others. PRI's are still the top rated mags, since they are very reliablle and allow loading to 2.305" for best accuracy and powder capacity. Barrett also allow longer loading, but they are even more $$ |
"Texas - the only state that ever kicked another country's ass."
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
"I'll never forget September 11, 2001, those who have fought and died, or those who continue to fight to avenge the deaths of over 3000 innocent Americans"
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6.8x43 is the only way for me... I see no use for anything else in a light-medium caliber.
It is my personal preference and I made sure my homework was done before securiing an upper. I then had it custom built with parts I selected. No one dictated the terms of the build and I was rewarded handsomely. I then opted for another upper which is built even better. I can also legally hunt with it here which is a plus if I need to kill to eat. It has impressed me greatly at distances to 400yds aswell as up close... it almost punched through a 3/8" thick cold rolled steel plate and exploded on impact leaving huge cavities and bubbles on the back end. I also retrieved some mangled projos from soft targets and the expansion was marvelous. I am very impressed and this is with loads at 2500-2600 fps... I can only imagine the impression a 3000 fps round will make.... To me... the sheet heeting the fan should have nothing to do with anything. Consider retail and internet cut off and the only way to supply would be to pillage and loot in a true shtf situation. Eveyone should be constantly preparing and supplying anticipating shtf so that when/if there is a catastrophe or whatever all you have to do is grab your shyt and go. Buy at least 500 rounds and forget about it. I dont plan on going rambo on 200 men while full auto so to me 500 potential kill shots in a single caliber is soothing enough to me. Not to mention the .12 guage / .45 acp and .50 ammo supply. 500-100 rounds is alot to lug around in a sedan or even a pick up now multiply that by all the other firearms you are stocking ammo for and think about that for a second... lugging around a family-food-clothing-survival gear etc and thousands of rounds of ammo.... not unless you have a bunker to retreat to... I dont. I try to be reasonable and practical when it comes to preparing for worst case. Ammo is important but its not everything. I didnt base my decisions on volume...I based it on precision...less is more to me...the more power the less I have to shoot... if I want to dump shells, I will get a .22lr and go to town...especially for plinking and training. Ammo price is not an issue either as there are places where you can get good deals on Hornady and S&B ammo for more around .75 cents a round. Costs about the same if not less than a box of .45 acp. When the supply hording ceases price per round will drop further... I keep every shell I shoot as I plan on reloading... so I can function outside the market if I cant get ammo from a supplier. Parts are easy to come by but even still I get two of each so I never have to worry about parts... 2 lowers / 2 uppers/ 2 barrels/ 2 bolts... I made sure they are assembled to run longer than I will be able to shoot... I keep extra small common parts on hand just in case like buffers and springs and what not. Here again... I am preparing for the worst from the get go. Mags are cheap as hell and can be had at as little as 12.00 so there is no excuse not to have "enough" mags just in case... I dont train to drop mags and forget them with any of my firearms so having 15 mags should suffice. With proper assembly and potential upgrades they should last longer than me... thing is... availability is about perception... where I live... shelves are empty besides .12ga Its about what you make of it... people tip toe around shyt becuase they are too afraid to jump in and its easier to just accept the normal state of bliss or ignorance or what have you. People are comfortable not changing. Why change? Why replace anything? Why correct mistakes? why progress? excuses are like pucker holes... either do or do not... On top of that... all the tit for tat about why not just get a .308 or all the little arguments over calibers under under a certain # of grains is silly... I sold the .300 win mag and bought a .50 upper in its stead.... problem solved...if a 110gr 6.8x43 round doesnt suffice and If a 500-600 grain rifled slug at 1600 fps isnt good enough then I can lay down behind 695gr of armor opiercing mayhem at 2750 fps and put any problem to rest... excuse the mindless rant |
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Just a bit of "food for though"
I made a 6.8 on a CZ 527 bolt gun a few years ago. I used an old Belgium made 270 Winchester barrel which I cut off at both ends. It (like many old europium 270s) was rifles 1-12" It shot wonderfully. Under MOA. I suspect that we could go as long as 1-13" to 1-14" and it would work fine with bullets from 80 to 115. The twist is less important then the rifling geometry. I think a 1- 13" twist with 3 grooves cut at four to one ratio would be as good as it could get. wide grooves and narrow lands produce a lot less pressure. The only down side to such rifling is loss of barrel life if you shoot them super hot (think full auto) which is not a big problem with semi-autos and not a problem at all with bolt guns. Any other thought on this? |
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Originally Posted By RealTeacher:
Just a bit of "food for though" I made a 6.8 on a CZ 527 bolt gun a few years ago. I used an old Belgium made 270 Winchester barrel which I cut off at both ends. It (like many old europium 270s) was rifles 1-12" It shot wonderfully. Under MOA. I suspect that we could go as long as 1-13" to 1-14" and it would work fine with bullets from 80 to 115. The twist is less important then the rifling geometry. I think a 1- 13" twist with 3 grooves cut at four to one ratio would be as good as it could get. wide grooves and narrow lands produce a lot less pressure. The only down side to such rifling is loss of barrel life if you shoot them super hot (think full auto) which is not a big problem with semi-autos and not a problem at all with bolt guns. Any other thought on this? Interesting, SH is that you? The 13 x 3 was done a few years ago by AR Performance, shoots up to 110s fine but the longer 130s and the Barnes 120 solid did not stabilize. He uses 12 twist 3 groove on his custom builds now and has hit 2950fps with a 110gr Accubond from a 20" 12 twist 3 groove barrel. Also getting 2800 from 110gr OTMs from the 16" 5R XT barrel. |
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When Size Matters 6.8 SPC
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When Size Matters 6.8 SPC
"THE STATE OF THE 6.8" ... JULY, 2009 (Page 3 of 8)
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