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RH, Here's my answer from page 5. Sorry if this was misleading, but I purposely quoted the barrel lengths because we have been testing a 24" stainless 11 twist DMR with 4 grooves. However, we have already compared the velocity of a 16" 11 twist, 4 groove SPC II and it got just over 200 FPS more than a 10 twist SAAMI: "...The performance difference is substantial: -Hornady Vmax commercial pressure = 2550 FPS, generally in 16 or 18" barrels. -Handload Speer TNT / 30.2 gr. RE7 in SS 11 twist, 4 groove, DMR 24" = 3197 FPS -Handloaded Sierra Pro Hunter with 32 grains H322 = 2770 FPS, without significant pressure signs in a SPC II, 11 twist, 4 groove , 16" rifle -Handloaded Barnes TSX / 29.5 grains RE10X (this almost identical to the SSA combat TSX) in 11 twist, DMR, 24" stainless, 4 groove barrel = 2796 FPS -Handloaded Barnes TSX 110/ 32gr. H335 in same SS barrel as above = 2880 FPS...." |
"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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Yeah, I think back on that page I was basically asking you guys HOW MUCH PERFORMANCE LOSS am I experiencing, by using a 16" bbl w/ SPC chamber and 1:10 twist??? It SOUNDS as if you are now saying that I am ONLY missing out on about 220fps?? This, IMO is not ideal, but surely not that big a deal, and not really THAT much performance. I guess, to be clear, and make sure we are on the same page here, I would like to ask how many FPS would a 16" bbl with SPCII/DMR chamber, and 1:11 twist offer? I will then compare this number to the 2550 fps I am getting, and come up with a BALLPARK IDEA on performance difference. Sure, it might not be exact, as the 2550 fps I'm referring to, is a Hornady 110 gr bullet (I think), but I'm just trying to figure out HOW MUCH performance loss I am seeing out of this 16" bbl with SPC/SAAMI chamber, and 1:10 twist??? Is there a better way to figure out the performance difference? This is the info I seek. Thank you my friend! |
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At this point, we are talking about 220 or so FPS difference in the 16" CL 10 twist, 6 groove, SAAMI versus the SPC II CL, 4 groove 16". I have not tested a Stainless DMR 11 twist 4 groove or 3 groove, nor a 12 twist in 16". For me that is a lot. Each user is different and has different needs. The extra 220-250 FPS is going to affect bullet drop, terminal performance of most bullets, and bullet choice. When you consider that the "MAX" loads for a CL, 10 twist SAAMI give you around 2500 FPS, and we don't even know how fast we can get bullets yet in the "improved" SPC barrels, then you have to figure there is good reason to continue this testing. |
"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"
Don't post here that often anymore. Just remember the original evolution of the 6.8SPC; it was developed for very specific environments; CQB (0-300M) in an M4/M16 compatible platform. Anything over is just gravy. BTW: just to answer a prior question, my MRP barrels are C/L. Edit to add: Maybe some here should re-read some of DocGKR posts. |
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Update: The date is set now. August 8th, 9th and 10th on Wild River Ranch's testing Facility at Goliad, near the historic Fannin Battleground. .....Where we kicked the shit out of Santa Anna, in revenge for the Alamo.    Remember the quote "Texas, the only state that ever kicked another country's ass." ?? Well, that happened just about 3 miles from my ranch. Hmmmmpf, if you met some of my neighbors, I can guarantee you that if another Mexican invasion ever again happens, these people (and I'll be right there with them) will kick their asses again, too. I definitely want those people on my side. We have at least 6 new barrels and uppers and a couple that have not yet been received. We have at least one very big surprise for all of you, too. If you are going to send an upper, please do it in the next week to ten days, as I will need to have it in hand by August 3 or 4, in order to have it on the ranch for the test. Also, for those of you sending test uppers. PLEASE, do not locktite the Muzzle Device on to the threads. Do not crank it on there so tight that only a Gorilla could get it off. Please just send a muzzle thread protector, or screw the other device on finger-tight. I can handle the rest. I do not want to damage your Muzzle device, and I plan on shooting all the uppers with the suppressor, so if they have 1/2 X 36 threads, locktited Vortices or no threads, then yours will be left out of this, and possible other testing phases. Stay Tuned. This one should be more informative that the last, with more data, and will address some of the weaknesses of the prior test. Oh, and don't forget the one huge surprise we have in store 
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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"
I was on vacation last week. Matt shot the Spec II upper: no failures whatsoever. We should have that on the way to you this week. I'll email you when it ships. Matt and I think that the threads are for a 9mm AR barrel. We have COMPLETELY NO IDEA what Smith and Wesson was thinking when they designed the barrel that way. (S&W needs to lay off the crack pipe.) Due to the threads being abnormal, our barrels will probably not be part of your suppressor testing. That is OK with us. As we discussed many weeks before, our main concern is comparing apples to apples, with the ONLY difference between barrels being the difference in chambers: Spec I versus Spec II. This is the only true way to see and measure the pressure differences. The Spec II barrel is a rechambered Spec I barrel, with the work done by Lothar Walther. Both barrels are 1:10 twist, same profile, Hard Blue, and the exact same configuration....the only difference being the chambers. Threads are exposed. Do not worry about damaging them. Matt and I plan on destroying (plasma cut) the barrels once your testing is complete, unless someone wants to buy the damned things. We have no use for them. (We may play with an EDM to which we have access, just for kicks.  )When Matt and I do testing, we change only one variable at a time. Please feel free to test to destruction. As Matt said on the phone, we like breaking stuff. Calculations and measurements are one thing; testing to failure is another thing, and usually more fun too. (You should have known me when I was a rocket scientist.) As we discussed previously, we've seen Douglas air gauged barrels, from the same lot, have different bore dimensions, thus causing extreme pressure differences. Lothar Walther digitally gauges the bore. Air gauging is an antiquated method of measuring bore variations. We have a few retired APG small arms inspectors reviewing the 6.8. We are unimpressed with the Hornady ammo we've been using. Maybe it was part of an early lot. Bullets are crimped to deformation: far to heavy a crimp for an accurate load. Powder burns clean. No signs of high pressures noted, but that does not accurately measure pressure though. P.S. Its great to be a Native Texan! Texas is the only independent nation reduced to statehood through TREATY. I am a firm believer in Texas seceding from the nation. |
SPR, SDM-Match, Lothar Walther barrels.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
A fantastic addition, which I am proud to say we are including, John. Thank you very much. I agree 100%. This time, we are going to address the concept of "variable isolation" as best we can. That was a criticism of the last test, whcih I believe was valid, but of course, getting 10, 12 or 20 barrels all identical save for a single difference was impossible, so we are getting as close as we can. I am still trying to get in touch with Steve from RRA, as I Would also like to include a SPCII 10 twist Wilson that is CM, but NON chrome lined. If any of you talk to him with any frequency, I would appreciate it if you could remind him to check his emal for the one I recently sent him. Oh, and yes, Texas is hanging on to statehood by a thread. If the Supreme court's Heller decision had gone wrong, you might have seen Texas and Montana forming Montexas or Texana 
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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"
Uh Oh...here comes the speculation  . Nope, sorry, we don't have P-Mags. Tell you what, you guys call and write Magpul, and I'll test them if they ever produce any. Gotta' tell ya...I'd LOVE to see some 6.8 P-Mags. |
"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"
| That will not happen. They have already looked into it and the space needed would not leave enough for the minimum thickness of the polymer they are made out of. T0 bad as that would have been awesome I do agree. So that leaves only PRi, CP, Barrett, and I think ProMag has one now out as well. |
God gave us two ears and only one mouth for a reason.
http://www.68forums.com
When Size Matters 6.8 SPC
http://www.68forums.com
When Size Matters 6.8 SPC
Tim's right, of course. The polymer would have to be so thick that it wouldn't fit in the mag well......unless.... they used an aluminum shell/skeleton and molded the polymer around that   
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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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Chris, Spec II upper mailed today via Priority Mail, insured. With luck and a good tail wind, you should have it by the end of the week. Matt came up with a better idea than plasma cutting or EDM for barrel destruction..... ....thermite. It seems that we have a local aerospace engineer who legally has some. At the point thermite is used, we believe that Hard Blue will fail.  hahaha!
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SPR, SDM-Match, Lothar Walther barrels.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
You guys are great!    Thermite?? Hell, I thought the plasma cutter was going to be cool  Anyway, thanks very much for sending the barrel. I am sure it will be a great addition to the test. I'll be looking out for it. |
"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"
Here are photos of it. Both Spec I and Spec II uppers are exactly the same, except for the chamber. The white foam tape keeps the brass from being marked by the shell deflector.  
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SPR, SDM-Match, Lothar Walther barrels.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
|
hi tech or known as Mister 6.8 Question, bought a 20in M1S upper long before there was ammo on the market. Hand lapped the barrel till a patch went through like glass. This is a hunting rifle (2 shots 2 deer the last 2 years) using 110Vmax at 2638fps. Gun shoots very well, best 5 shot group is .385 at 100yds. I read someplace that there is no velocity gain after 18in of barrel is that true? The rifle is heavy to pack around the mountains ( I'm not getting any younger) and crossed my mind to cut the barrel down some. What do you think? VM Don't mean to hijack |
[quote]Originally Posted By jrucker2004:
heh, I don't think so bub.
not after seeing your handywork in Arlington. <img src=/images/smilies/icon_smile_wink.gif border=0 align=middle>[/quote]
heh, I don't think so bub.
not after seeing your handywork in Arlington. <img src=/images/smilies/icon_smile_wink.gif border=0 align=middle>[/quote]
First off, the "myth" is busted. What is true is that the .30 Remington parent case is so efficient that somewhere around 85-90% of the cartridge's efficiency can be squeezed out of the 16" barrel length, depending upon proper bullet and powder choice. However, once that powder is selected (let's say it's RE7, which is still producing propellant gases at 20") , then you are still gaining velocity after 16" at a rate of around 30 FPS per inch. Some say that trade off isn't worth it. Well, in YOUR barrel, you are getting good groups and you have killed deer with it. 2638 FPS will probably make a VMax deform more like a traditional soft point, rather than explode, so I think you have a good formula and given those groups you've achieved, I would NOT cut that barrel down. You can't be sure it will ever perform like that again. Lastly, if you want a "carry around the mountains" rifle, buy a Cardinal Armory 16" superlight. This gives you the other end of the spectrum. It is very light, and with its longer chamber and 4 groove 11 twist rifling, it can accept the "improved" version of 6.8 ammo we've seen developed in the last few years. That means that you can shoot loads producing 2650 FPS from the 16" barrel, though they will be a little hotter. I certainly wouldn't sell, cut down or change your M1S barrel. Keep killing stuff with it, and use if from a stand or when stationary. I own both a CA 16" superlight, and a 20" barrel. One for stalking on foot and the other for stand hunting. I get about 120 FPS more from the 20" barrel, especially with 10X and RE7. Hope this helps ETA; here are a few examples of what I was talking about. The 32 grain H322 load is more of a "proof load' for testing, and I don't shoot it often. I wouldn't try that one at home. As you can see, the 24" barrel continues to produce velocity gains, though most would consider it impractical. Hornady Vmax commercial pressure = 2550 FPS, generally in 16" barrels. -Handloaded Sierra Pro Hunter with 32 grains H322 = 2720 FPS, without significant pressure signs in a SPC II, 11 twist, 4 groove , 16" rifle -Handloaded Barnes TSX 110/ 32gr. H335 in 24" stainless, 4 groove barrel = 2880 FPS -Handload Speer 90 grain TNT / 30.2 gr. RE7 in SS 11 twist, 4 groove, DMR 24" = 3197 FPS Obviously, these are three different loads, but if you look at the velocities, you can see that those eclipsing 2850 were fired in the 24" test barrel, before Constructor cut it down. Only when you really load hot, can you get the 16" barrel to around the 2700 mark, and you have to be quite careful in that zone, because the pressure is likely to be in the 60K PSI range. Our experience has been that the longer the barrel, the more velocity you get. If we see bolt guns built, then the COAL will get longer and powder charges will rise. That's when you'll really start to see a difference. |
"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"
|
Thanks for the reply, I like the idea of a light 16" barrel that could push a 110 Vmax at close to what I'm using now. And you are right about the Vmax at 2638. It does not explode, but mushrooms nicely making a good hunting bullet. I say this after examining the damage to the deer. Can the barrel you recommended shoot sub minute? One other note, H322 is the only powder that would shoot in my gun. H335 shot over 2" groups. Go figure. Thanks again. VM |
[quote]Originally Posted By jrucker2004:
heh, I don't think so bub.
not after seeing your handywork in Arlington. <img src=/images/smilies/icon_smile_wink.gif border=0 align=middle>[/quote]
heh, I don't think so bub.
not after seeing your handywork in Arlington. <img src=/images/smilies/icon_smile_wink.gif border=0 align=middle>[/quote]
VM, How does this grab ya'? I am still shaking my head at the accuracy potential of this little CA superlight barrel. Now, granted these are 3 shot 100 yard groups, slow fire. But this kind of performance has not been too uncommon among the CA barrels. I have loved everything about this upper since I got it...handling, accuracy and weight. It even looked good. You could not pry this upper from my cold, dead fingers. It is with me forever..... 
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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"
|
Nice group and I see your barrel likes H322 also. What a great deer rifle. Looks like I need a new upper--damn! Thanks for your testing on the barrel twist and chambers. Who would have thought that it made that much difference in velocity and pressure. VM |
[quote]Originally Posted By jrucker2004:
heh, I don't think so bub.
not after seeing your handywork in Arlington. <img src=/images/smilies/icon_smile_wink.gif border=0 align=middle>[/quote]
heh, I don't think so bub.
not after seeing your handywork in Arlington. <img src=/images/smilies/icon_smile_wink.gif border=0 align=middle>[/quote]
AR Variants Mod and Juris Doctor (in training)!
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Feel free to post specs on your barrels over on 68forums.com I am sure the membership there would love to heard about them. |
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Oh, how the ghost of you clings...
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AFman, Do these Lothar 6.8 barrels have conventional or polygonal rifling? Bbl Length? and how many rifling grooves? PS thanks for the test contribution... Looking forward to results... |
20" barrel 6 groove Conventional rifling I am looking forward to the results too. I like the apples to apples idea. All that is needed is a strain gauge (transducer) to measure the pressures. I wish that we had a third barrel, without Hard Blue, to see the difference between an untreated barrel and a Hard Blue barrel. I should get around to posting this of the 6.8 forum. |
SPR, SDM-Match, Lothar Walther barrels.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
| If you have to shoot, Hard Blue is not bothered by mud. |
SPR, SDM-Match, Lothar Walther barrels.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
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Here's what I have in hand for the test this weekend: - Superior barrels 20" SS, fluted, Hard-Blued SAAMI, 10 twist - Superior " 20" SS, fluted, Hard-Blued SPCII, 10 twist - DPMS 16" M4 profile, SAAMI chamber, 10 twist, CL - Ko-Tonics / CA 16" superlight, SPC II, 4 groove, 11 twist, CL - Ko-Tonics / CA 20" fluted, SPC II, 4 groove, 11 twist, CL - Denny's / WOA 16" stainless, SAAMI, 11 twist - AR15 Performance 20 SS, 11 twist, 6 groove, DMR chamber, - AR15 Performance 20" SS, 12 twist, 6 groove, DMR chamber - AR15 Performance 20" SS, 13 twist, 3 groove, DMR chamber -unfortunately, we don't have the LWRC M6A3 upper in hand yet. Jesse had promised me one for testing, but I suspect that given the recent increase in military interest in the gun, he hasn't had enough uppers to go around. Don't anyone get upset about this. If we don't have an LWRC M6A3 upper for this test and the reason ends up being that they were all tied up with military testing so that our guys could get them sooner to kill terrorists....Then I think our reaction should be that we're proud and supportive of anyone making 6.8 guns that might end up in the hands of US Soldiers. Keep your fingers crossed. Otherwise we have some surprises, including some things nobody has ever tested before, from some of the very generous people that donated their wares to this ambitious project. ETA: I also want to take the time to thank Art Kalwas from SSA once again. Without his help in securing the ammo we needed, including some "Very special" ammo we needed for specific tests, this could never have happened. Thank you very much, kind sir. You have many hogs here with your name on them... |
"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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Update: We're finished with the (second half of ) 2008, 6.8 SPC performance test. We have a lot of great data to show you, and some surprises, too. We saw some very exciting things in this test and we are all anxious to show them to you. Everyone is in one piece, thankfully, but a little tired from lack of sleep. We tested ALL day long, then hunted hogs at night....most of the night, too  Harrison (Constructor), and Tim W are definitely capable and resourceful. I absolutely could never have done any of this without their help and expertise, so I want to thank them first and foremost. I think we held ourselves to a high standard, but I will allow you all to judge. The report is now being complied and we hope to release it within 2 weeks, if possible. Special thanks also goes to the manufacturers which supplied us with testing materials. (Most were purchased or lent, and are being returned). A complete list of their names will be forthcoming. I would like to ask that you hold specific questions until we get the report posted. This way, I won't accidentally leak or divulge information until it has been properly recorded and collated. We prefer to release all the info at once, then field questions thereafter. Thanks for your patience. I think you will find this worth the short wait..... HTR |
"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"
Would you send us a copy of the report when completed? |
SPR, SDM-Match, Lothar Walther barrels.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
Yes, absolutely. Thank you very much for your help in participating, guys. We do appreciate it. |
"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"
Good luck with that. I am not saying that the libs aren't making a good case for it, nor am I saying I wouldn't want to join you all in this suicide mission if Obama steals the Presidency, but realistically--good luck with that. |
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Anyone know why Cardinal Armory is putting this disclaimer on their website now? NOTICE: These barrels are NOT guaranteed to handle Silver State Armory "combat" loads. I thought the SPCII chamber and 1:11 twist was good to go with hotter loads. |
<font color=red><font size=2>99%er</font id=red></font id=s2>
They are saying that because Superior Plating (their former Chrome plater) apparently was doing a very poor job of plating their barrels. As a result, some of them are several thousanths of an inch too small in bore diameter because of this chrome buildup. It cannot be removed with a practical method, so they are now forced to say this because they cannot be sure which barrels are affected. If you get a CA barrel with the proper plating, and bore diameter, it WILL handle combat and hot reload ammo. This is simply a growing pain that occurs with many Chrome Lined barrels, and it illustrates this one very important point, which I mentioned earlier in this thread. That is: even with the "optimum" specs of SPCII or DMR chamber, and 11, 12 or 13" twist, if you have a very tight bore, that is going to negate the good characteristics and spike pressure badly. An inordinately tight bore is going to do this no matter how slow your twist or how large your chamber. **See this same statement I made in the first few pages after I released the first test results.** I said this long before CA realized that their plater had messed up the barrels. Our recent test involved two CA barrels, one that was affected and one that was not. You will soon see the results, although we were not able to put the pressure transducer on the affected barrel for reasons I'll expliain when the text and report are posted here. It should be ready in another week. |
"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"
| Well this worries me, because I bought a 16" SPR barrel about a month before I heard about the chrome plating issue which leads me to believe I may have a barrel with bad plating. I haven't put any rounds through it yet, I hope I don't see any ejector swipes. |
<font color=red><font size=2>99%er</font id=red></font id=s2>
Do this: Get a lead "slug".... push it through the barrel and measure the lands and bore to determine the size. You should see .270 lands and a .277 bore. BFarrin posted a very nice description of this same process in a "variants" thread. You then can simply shoot some SSA commercial 115 grain OTM's and if all is OK, then get some SSA combat 115 OTM's. This is the largest bullet with greatest bearing surface, and if any will spike pressure this one is it. If you are seeing popped primers...stop. If not, and there aren't even ejector marks, you are GTG. Very faint, shiny ejector marks don't concern me much since some rifles can produce them stemming from timing issues or a rough chamber, but this is all the more reason to measure your bore's diameter. If it is smaller than .2685, then you should not shoot the combat loads. Please feel free to IM me if you need more info/support. Don't let this get you down. Tim will eventually make this right, I know he will. At the absolute worst, you might have to replace a barrel. There are many worse things in this life....for example, you could be in Iraq or Afghanistan, away from your family, watching friends / fellow soldiers getting killed. |
"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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Not to put a damper on the lead slug idea but it will not clearly give the dimensions of the barrel. The issue as Tim Hick Cardinal Armory has also found out and posted about is the slug will form to the area of the bore it is in as the force to push it thru is great enough to have it form increasing or decreasing as it goes thru the bore. Given this the only spec you will get is the spec of the bore at the muzzle. In most of the barrels tested the area right at the muzzle did not seem to be where the build up occurs. The build of chrome doesn't not happen evenly in this instances but seems to have high spots etc.. at different points in the bore. You can check the evenness of the land by dropping a precision gauge down it but the lands only represent 70%^ of the total bore area so it is limited. But from what we have seen if the lands are tight so is the rest of the bore in those areas. Honestly the best way at this point to see if you have a barrel that has a chrome build up is to shoot the SSA 115 Combat loads. Shoot 3 and check them. If they look ok shoot 5 rapidly and check if they look good or at the most you see very faint swipes you are GTG. IT is certainly the simplest way to do it. As what really matters here is is performance effected. This is not the thread to have this discussion so if more needs to be posted could it please be done in its own thread so we can keep this one on point. The report is really taking form and should be done and posted in the next few of days if it goes OK. You wouldn't think putting something like this together would be that big of an undertaking but let me tell you I have found out the hard way. When certain images don't transfer proeprly and you have to screw with pictures over and over to try and et the best lighting of the cases etc.. and there add in charts and narrative not to mention tweaking it here and there it turns into a major amount of work. I easily with out including the actual trip to Texas and all of that time have 45-50 hrs in so far and I look at and go this shouldn't have taken that long. The real time killer is when you have to redo things over and over to get it to work. Well enough whining, I hope to have it done soon. |
Are Adobe products being their usual helpful self? And... ...of course... Microsoft has its own endearing issues. |
SPR, SDM-Match, Lothar Walther barrels.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
How would you ave guessed!?! I guess I can't be too mad about all the bugs as I made a prosperous carrier making those products and networks based off them work perfectly. But man when it comes to being the end user and having to get things to work right Many times I had the laptop over head ready to send it air born. I have to admit I was caught a bit off guard by the actual amount of time the whole thing consumed. Some of it couldn't be avoided and some was simply finding the best way. Naturally from what we have learned I certainly think we could cut the total amount of time in half but even with that it is still a good amount of work. Forgetting all the BS I went thru with some issues that I posted about on 68forums and don't care to rehash here It was still a considerable amount of time when you really add it up. From what I have seen and experienced, given one of the goals of your company is to provide barrels with chambers set to match specs to achieve maximum accuracy, I would seriously consider using the DMR chamber. Your barrels are not chrome lined and when the report comes out you can see how the DMR varies compared to the SAAMI and SPCII. It is without a doubt the chamber for the 6.8 when accuracy is the main goal of the three. IMO for non-CL barrel and possibly not for ones that may see lots of F/A fire the DMR chamber represents the best configuration. For use where you really need the larger tolerances such as with CL or where it may see the abuse of tons of full auto fire with out maintenance cleaning the SPCII makes more sense. The only time I could see the SAAMI being possible choice is if it were used in a bolt gun as you can seat into the lands but then we are speaking of a bolt gun and once again the DMR would be a better choice. Sure you may want to custom fit the throat in a true one off match barrel but that would be a expected change for any barrel at that level. I would apply the chamber choices similarly as they are done with the .223/5.56. For the most part it is either the true NATO 5.56 chamber for the combat guns or it is some chamber that is similar to the Wylde which is the most famous of the match chambers along with Noveski's 0 Match Chamber that allow for use of all ammo with match accuracy being a goal. With my DMR chambered barrel in the AR 0.5 MOA is the norm with tuned loads and down to .25 is possible when everything comes together (mainly my shooting being on). Now my AR has many tweaks that aren't readily noticeable but are what combines to help get that extra little bit of accuracy. Constructor has done and hand held me thru the various tweaks he does to get that last bit of accuracy and some I do to make sure I get utter reliability. I also will say I was very impressed with the Hard blue coating on those barrels. It looked flawless and was a very pleasing color shade. It also stood up to the type of a abuse you had claimed it would. I certainly would have been able to get thru chrome plating with a cutting wheel but I could not so much as make a scratch on the hard blue. That is impressive. The only question I have about it deals with the temps involved in the application. If you could PM me or we could talk as I know you are very guarded about any info specific to the process itself. |
God gave us two ears and only one mouth for a reason.
http://www.68forums.com
When Size Matters 6.8 SPC
http://www.68forums.com
When Size Matters 6.8 SPC
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Howdy Tim_W, The below link shows the temps that Hard Blue has withstood. It is at the bottom, but the reading getting there has a fair amount of information. We were unable to take temp measurements in the chamber and throat area. We figure that the chamber and throat had to be hotter than where we took the readings. We were way past the cook-off temp. To avoid a cook-off, it was insert fresh mag, aim, pull trigger once until mag was empty. We are still Final Report: AR15 1000 Round Full Auto Test BTW, a gas tube will melt at around 150 rounds full auto. I pulled the trigger ONCE on a C-mag and emptied all 100 rounds. Immediately, I put in another C-mag. The gas tube turned to spaghetti near the 50 round mark. After replacing it, I used a combination of 30-round mags and C-mags. Gas tube got hot enough to bend, but I kept it a low red color; it lived to the end. I had to wear my fireman gloves to keep my hands from burning. BTW, my gloves are toast too. When I shoot full auto, I shoot FULL auto.
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SPR, SDM-Match, Lothar Walther barrels.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
| That is awesome. Thanks for the link I always enjoy learning so the extra info is welcome. If you were ever to offer this service for customers own barrels I think it would be extremely popular as well. I know I would certainly consider it. A hummer barrel that lastly many times longer sounds like a dream come true. If it is in the data in the link don't feel you need to answer but have you found a round count by whihc you start to see signs of gas port erosion and or throat wear ie heat cracking, general erosion, etc..? |
God gave us two ears and only one mouth for a reason.
http://www.68forums.com
When Size Matters 6.8 SPC
http://www.68forums.com
When Size Matters 6.8 SPC
|
I am a pessimist; I figure at least 10K rounds of accurate life: id est, extremely little throat erosion. Mark Humprheville estimates 15K-20K rounds. Below is another excerpt of released information. Once again, a fair bit of reading, but good information. Make sure to look over the firing and especially the cleaning schedule. Examination of AR barrel, #22, with 5000 rounds. |
SPR, SDM-Match, Lothar Walther barrels.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
www.superiorbarrels.com www.shop.superiorbarrels.com 678-437-7821
Every good man deserves a good rifle. That starts with a Superior Barrel.
Hard Blue: no other barrel lasts longer & shoots tighter.
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The release of the report is now imminent. It has been put together and we are just proofreading the final copy. Pictures are being added today for the final release tomorrow. I think you will find it interesting, especially as regards velocities, and the related pressure testing. Tim W has done an incredible job, has spent 40-50 hours in Adobe's maze, and since he wrote it up this time, I didn't have to. I am greatly in his debt.BTW, so are all of you Our initial impression was that we would post this as a stand-alone thread, then lock it immediately. Mods will you take care of that for us? Then, all of you can reply and discuss in this thread, if deemed appropriate by the site staff. Finally, ladies and gentlemen, the wait is over. Give us just one more day. |
"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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