User Panel
User Panel
User Panel
|
Posted: 6/24/2009 7:30:13 PM EDT
[#1]
The chart is around here somewhere, but I believe that under 18 inches the .308 peters out pretty quick. ETA: unless it's strictly for CQB of course.
Some one will be along shortly to confirm this. |
|
|
|
Posted: 6/24/2009 7:50:51 PM EDT
[#2]
Here are some numbers with Quickload software. These are not real, they are computer modeled.
308 Win. 168 grain SMK, BLC-2 - 47.5 grains Inches of barrel/ muzzle speed (fps) 14.5/ 2490 16/ 2555 18/ 2629 20/ 2693 22/ 2748 24/ 2796 147 grain FMJ, IMR 4064 - 46.5 grains 14.5/ 2564 16/ 2633 18/ 2712 20/ 2779 22/ 2838 24/ 2890 154 grain FMJ, BLC2 - 47 grains 14.5/ 2539 16/ 2606 18/ 2682 20/ 2748 22/ 2805 24/ 2856 Note - I assume the backwards powder weight difference between the 168 grain and 154 grain bullets has to do with bullet jacket bearing surface differences or jacket thickness. |
|
|
|
Posted: 6/24/2009 8:03:35 PM EDT
[#3]
Quoted:
Here are some numbers with Quickload software. These are not real, they are computer modeled. 308 Win. 168 grain SMK, BLC-2 - 47.5 grains Inches of barrel/ muzzle speed (fps) 14.5/ 2490 16/ 2555 18/ 2629 20/ 2693 22/ 2748 24/ 2796 147 grain FMJ, IMR 4064 - 46.5 grains 14.5/ 2564 16/ 2633 18/ 2712 20/ 2779 22/ 2838 24/ 2890 154 grain FMJ, BLC2 - 47 grains 14.5/ 2539 16/ 2606 18/ 2682 20/ 2748 22/ 2805 24/ 2856 Note - I assume the backwards powder weight difference between the 168 grain and 154 grain bullets has to do with bullet jacket bearing surface differences or jacket thickness. So by looking at this chart it looks like I will only lose about 60 fps. between the 16 and 14.5 inch model. That dosent seem to bad. I assume. Sorry but i dont know much about thus aspect. thank you for the help. |
|
|
|
Posted: 6/24/2009 10:29:53 PM EDT
[#4]
If you want an entry weapon, go for it. Sniper weapon, that length would have a pronounced disadvantage. Keep that over 20".
|
|
|
|
Posted: 6/25/2009 8:17:03 PM EDT
[#5]
Quoted:
If you want an entry weapon, go for it. Sniper weapon, that length would have a pronounced disadvantage. Keep that over 20". Why would it suffer at 20"?? Barrel length has little if anything to do with accuracy. |
|
|
|
Posted: 6/25/2009 9:03:16 PM EDT
[#6]
I don't think that that chart is a good indicator,
There is a chart on from the shooting times, in which the 168amax from a 16in doesn't put out what is indicated on this chart |
|
|
|
Posted: 6/26/2009 9:19:48 AM EDT
[#7]
Does a .308 with that short of a barrel have a tremendous muzzle flash? Just curious.
|
|
|
|
Posted: 6/26/2009 12:10:06 PM EDT
[#8]
What you lose in "punch" you'll get in muzzle blast, I bet.
|
|
|
|
Posted: 7/8/2009 8:07:01 AM EDT
[#9]
|
|
|
|
Posted: 7/8/2009 8:49:06 AM EDT
[#10]
|
|
|
|
Posted: 7/8/2009 9:00:41 AM EDT
[#11]
"Why would it suffer at 20"?? Barrel length has little if anything to do with accuracy."
Barrel length has a lot to do with accuracy at distance. Barrel length > velocity > supersonic range |
|
|
|
Posted: 7/8/2009 9:24:27 AM EDT
[#12]
Quoted:
"Why would it suffer at 20"?? Barrel length has little if anything to do with accuracy."
Barrel length has a lot to do with accuracy at distance. Barrel length > velocity > supersonic range Might lose some range but not accuracy. |
|
|
|
Posted: 7/8/2009 9:47:23 AM EDT
[#13]
Quoted:
Does a .308 with that short of a barrel have a tremendous muzzle flash? Just curious. I'd imagine it would. 308 is similar enough in several ways to 5.56 that it will suffer from shorter barrels. If you want a short range, short barreled thumper gun, its hard to beat a brush cartridge that uses magnum handgun powders. |
|
|
|
Posted: 7/8/2009 9:58:46 AM EDT
[#14]
I was hitting out to 400 yards no problem with my 14.5" POF 308. Accuracy is not the issue, you just have to compensate a little more for the bullet drop. The muzzle blast is something else though... WOW!
|
|
|
|
Posted: 7/8/2009 10:08:29 AM EDT
[#15]
"Might lose some range but not accuracy."
Supersonic range is accurate range. Once the bullet goes subsonic, accuracy goes to $#!^. |
|
|
|
Posted: 7/8/2009 12:06:13 PM EDT
[#16]
Quoted:
"Might lose some range but not accuracy."
Supersonic range is accurate range. Once the bullet goes subsonic, accuracy goes to $#!^. And that's why I said range may suffer. Accuracy itself isn't affected by barrel length. Supersonic is about 1,125fps and a short barrel will go below that at a shorter distance, but even a 24" barrel shooting M118LR@800m is going to suffer. |
|
|
|
Posted: 7/8/2009 3:35:55 PM EDT
[#17]
And that's why I said range may suffer
Oh for fucks sake. You are saying accurate range will suffer. Same goddam thing as saying accuracy suffers at distance, which is what I said. Argumentative fucks. |
|
|
|
Posted: 7/8/2009 4:12:06 PM EDT
[#18]
Quoted:
And that's why I said range may suffer
Oh for fucks sake. You are saying accurate range will suffer. Same goddam thing as saying accuracy suffers at distance, which is what I said. Argumentative fucks. Thats really uncalled for here in Tech. Warning sent. You know it. read the code of conduct SITE STAFF/OWNERS have posted and follow it. Or else refrain from posting here, thanks. |
|
|
|
Posted: 7/8/2009 5:37:54 PM EDT
[#19]
Quoted:
And that's why I said range may suffer
Oh for fucks sake. You are saying accurate range will suffer. Same goddam thing as saying accuracy suffers at distance, which is what I said. Argumentative fucks. I don't think the OP was worried about 1000m. |
|
|
|
Posted: 7/8/2009 10:38:54 PM EDT
[#20]
I don't think the OP was worried about 1000m.
I wasn't addressing the OP. I was addressing your question regarding 20" barrels on sniper rifles. That implies distance shooting. All of which you understand perfectly well, but pretend otherwise for the sake of being argumentative. I apologize to the owners of the site for breeching decorum earlier, but you are being willfully obtuse and unecessarily contentious in response to information that you requested and that I offered politely and in good faith. Your handle is appropriate to your behavior, which is not. |
|
|
|
Posted: 7/9/2009 4:10:11 AM EDT
[#21]
Here are some data from the Hogdon reloading manual #27. The data are for 15 and 24 inch barrels, but you can linearly extrapolate and get an idea of the delta* in velocities. The velocities probably do not drop off linearly but the assumption is good enough to get a pretty good idea of how much velocity you are losing.
168 grain SMK, BLC- BCL-2 47g= 15/2490––24/2750: delta=-29fps/inch Varget 46= 15/2580––24/2731: delta=-17fps/inch Using the QuickLoad data that Bend posted–– 14.5/ 2490––24/ 2796: delta=-32fps/inch So bottom line is a 14"-ish barrel will push a 168g bullet between 2400-2500 fps. *delta= (15in velocity-24in velocity)/(14in barrel-24in barrel) Quoted:
Here are some numbers with Quickload software. These are not real, they are computer modeled. 308 Win. 168 grain SMK, BLC-2 - 47.5 grains Inches of barrel/ muzzle speed (fps) 14.5/ 2490 16/ 2555 18/ 2629 20/ 2693 22/ 2748 24/ 2796 Quoted:
I don't think that that chart is a good indicator, There is a chart on from the shooting times, in which the 168amax from a 16in doesn't put out what is indicated on this chart The caveat is always "mileage may vary" 
I hope this helps. 320pf |
|
|
|
Posted: 7/9/2009 4:27:10 PM EDT
[#22]
Quoted:
Here are some numbers with Quickload software. These are not real, they are computer modeled. 308 Win. 168 grain SMK, BLC-2 - 47.5 grains Inches of barrel/ muzzle speed (fps) 14.5/ 2490 16/ 2555 18/ 2629 20/ 2693 22/ 2748 24/ 2796 147 grain FMJ, IMR 4064 - 46.5 grains 14.5/ 2564 16/ 2633 18/ 2712 20/ 2779 22/ 2838 24/ 2890 154 grain FMJ, BLC2 - 47 grains 14.5/ 2539 16/ 2606 18/ 2682 20/ 2748 22/ 2805 24/ 2856 Note - I assume the backwards powder weight difference between the 168 grain and 154 grain bullets has to do with bullet jacket bearing surface differences or jacket thickness. Intereseting, but I'd like to see a chart that shows each barrel length and the range at which each goes subsonic. |
|
|
|
Posted: 7/9/2009 6:10:47 PM EDT
[#23]
Bend,
Ask and you shall receive. Here are the tables that you asked about. I used the QuickLoad velocities to calculate when the bullets drop to subsonic. I did it for just the 14 and 20-in barrles. I did one complete table. If you want to see the results in more detail, go to this webpage and have fun. http://www.eskimo.com 168 SMK 14-in barrel(m.v.=2490fps) Range===Vel.====Mach#===energy 0.0=====2496.6==2.236===2324.7 100=====2303.7==2.063===1979.3 200=====2119.2==1.898===1675.1 300=====1935.2==1.733===1396.8 400=====1760.7==1.577===1156.3 500=====1598.1==1.431===952.6 600=====1443.0==1.292===776.6 700=====1306.2==1.170===636.3 800=====1191.2==1.067===529.2 880=====1117.0==1.001===465.4 900=====1101.0==0.986===452.1 1000====1032.9==0.925===397.9 20-inch barrel(m.v.=2693fps) 1130====1116.9==1.000===465.3 Winchester 147gr FMJ 14-in barrel(m.v.=2564fps) 910=====1121.9==1.005===410.8 20-inch barrel(m.v.=2779fps) 1010====1120.9==1.004===410.0 Lapua 154gr scenar 14-in barrel(m.v.=2539fps) 920====1115.2===0.999===425.2 20-inch barrel(m.v.=2748fps) 1020===1121.6==1.005===430.1 320pf Quoted:
Quoted:
Here are some numbers with Quickload software. These are not real, they are computer modeled. 308 Win. 168 grain SMK, BLC-2 - 47.5 grains Inches of barrel/ muzzle speed (fps) 14.5/ 2490 16/ 2555 18/ 2629 20/ 2693 22/ 2748 24/ 2796 147 grain FMJ, IMR 4064 - 46.5 grains 14.5/ 2564 16/ 2633 18/ 2712 20/ 2779 22/ 2838 24/ 2890 154 grain FMJ, BLC2 - 47 grains 14.5/ 2539 16/ 2606 18/ 2682 20/ 2748 22/ 2805 24/ 2856 Note - I assume the backwards powder weight difference between the 168 grain and 154 grain bullets has to do with bullet jacket bearing surface differences or jacket thickness. Intereseting, but I'd like to see a chart that shows each barrel length and the range at which each goes subsonic. |
|
|
|
Posted: 7/9/2009 6:34:43 PM EDT
[#24]
Quoted:
What model Surefire light is THAT?!  SF can't do that with help... gotstobe a FENIX. 
BTW, anything less that 16" {18", personally} for .308 and a wise man would go 6.8, OP. |
|
|
|
Posted: 7/10/2009 10:47:11 AM EDT
[#25]
Quoted:
Quoted:
What model Surefire light is THAT?! SF can't do that with help... gotstobe a FENIX.
BTW, anything less that 16" {18", personally} for .308 and a wise man would go 6.8, OP. I agree the 6.8 would be better with < 18" barrel only because of more capacity and lighter weight. Those are the only advantages I can see with a 2 minute debate in my head. With the above charts the 168gr SMK .308 @ 100 yards out of a 14.5" barrel has more energy than the 6.8 does at the muzzle from a 16" barrel. 1900~2000~ ft lbs. So, the .308 is still more powerful even after converting its power into a muzzle blast. The price of the ammo is about the same. A box of average .308 is actually less expensive than the cheapest 6.8. Plus you can buy .308 within a stones throw of most people's homes. This is the info I needed to hear in order to concrete that a 16"-18" .308 is a good idea. Even though you're losing power, it is still more powerful than any other smaller popular round even if you give the other round a 100 yard advantage. I am really hoping the XCR-M .308 is released this year with an 18" option. That is what I am currently eyeballing. Gives me a hunting/battle rifle like American's used to have during the Revolutionary War. I don't want a million rifles/women... I just want one perfect one. Given these charts and research, I'm pretty comfortable if they release a 16" option with an FSC30 muzzle brake that is, haha. Brent |
|
|
|
Posted: 7/10/2009 8:51:35 PM EDT
[#26]
Quoted:
I am really hoping the XCR-M .308 is released this year with an 18" option. That is what I am currently eyeballing. Gives me a hunting/battle rifle like American's used to have during the Revolutionary War. I don't want a million rifles/women... I just want one perfect one. Given these charts and research, I'm pretty comfortable if they release a 16" option with an FSC30 muzzle brake that is, haha. Brent This year would be great, but I think that is optimistic. I get the feeling that RA won't be releasing the XCR-M until next year - summer. Would love to be wrong... |
|
|
|
Posted: 7/12/2009 8:46:20 AM EDT
[#27]
Quoted:
Bend, Ask and you shall receive. Here are the tables that you asked about. I used the QuickLoad velocities to calculate when the bullets drop to subsonic. I did it for just the 14 and 20-in barrles. I did one complete table. If you want to see the results in more detail, go to this webpage and have fun. http://www.eskimo.com 168 SMK 14-in barrel(m.v.=2490fps) Range===Vel.====Mach#===energy 0.0=====2496.6==2.236===2324.7 100=====2303.7==2.063===1979.3 200=====2119.2==1.898===1675.1 300=====1935.2==1.733===1396.8 400=====1760.7==1.577===1156.3 500=====1598.1==1.431===952.6 600=====1443.0==1.292===776.6 700=====1306.2==1.170===636.3 800=====1191.2==1.067===529.2 880=====1117.0==1.001===465.4 900=====1101.0==0.986===452.1 1000====1032.9==0.925===397.9 20-inch barrel(m.v.=2693fps) 1130====1116.9==1.000===465.3 Winchester 147gr FMJ 14-in barrel(m.v.=2564fps) 910=====1121.9==1.005===410.8 20-inch barrel(m.v.=2779fps) 1010====1120.9==1.004===410.0 Lapua 154gr scenar 14-in barrel(m.v.=2539fps) 920====1115.2===0.999===425.2 20-inch barrel(m.v.=2748fps) 1020===1121.6==1.005===430.1 320pf Quoted:
Quoted:
Here are some numbers with Quickload software. These are not real, they are computer modeled. 308 Win. 168 grain SMK, BLC-2 - 47.5 grains Inches of barrel/ muzzle speed (fps) 14.5/ 2490 16/ 2555 18/ 2629 20/ 2693 22/ 2748 24/ 2796 147 grain FMJ, IMR 4064 - 46.5 grains 14.5/ 2564 16/ 2633 18/ 2712 20/ 2779 22/ 2838 24/ 2890 154 grain FMJ, BLC2 - 47 grains 14.5/ 2539 16/ 2606 18/ 2682 20/ 2748 22/ 2805 24/ 2856 Note - I assume the backwards powder weight difference between the 168 grain and 154 grain bullets has to do with bullet jacket bearing surface differences or jacket thickness. Intereseting, but I'd like to see a chart that shows each barrel length and the range at which each goes subsonic. If this is in regards to factory ammo it is not accurate, I saw a test from a socom that didn't get those #'s 
Now if it is handloads, thats another story |
|
|
|
Posted: 7/14/2009 3:15:04 PM EDT
[#28]
Just got finished the "Break In" on my DPMS AP4 308 with the 16 inch barrel
Here is the results I got,knowing that scope hight,wind moving back to forward or reverse etc so take the results for what it is worth  Note used an old beat up 3x9 Redfield dialed in at 9 X
168 MK Moly 44 Varget,Federal cases CCI BR2 primed 1.5 inch high at 100 yards zero at 200 yards outstanding accuracy This is my standard Accuracy, Got to load in 308 win.
150g FMJBT Hornady Moly 44 gr Varget, LC cases,CCi BR primed 2 inch high at 100 yards zero at 200 yards good accuracy 175 MK Moly 43 Varget (standard accuracy load ) Fed cases,CCI BR2 primed 2.5 inches high at 100 yards Zero at 200 yards good accuracy Hope this helps !! John |
|
|
|
Posted: 7/14/2009 8:07:23 PM EDT
[#29]
Thanks for the info guys. As stated by another post who is correct, I dont plan to shoot beyond 100yds, mostly 100-300ish some times more. Thanks
|
|
|
|
Posted: 7/17/2009 6:17:19 PM EDT
[#30]
Quoted:If this is in regards to factory ammo it is not accurate, I saw a test from a socom that didn't get those #'s
Now if it is handloads, thats another story The software models handloads. Also, it does NOT compensate for gas operation (at least I have not found a way to do it). So consider all speeds from a bolt action. A gas gun would have less speed. |
|
|
|
Posted: 7/17/2009 9:06:06 PM EDT
[#31]
Quoted:
And that's why I said range may suffer
Oh for fucks sake. You are saying accurate range will suffer. Same goddam thing as saying accuracy suffers at distance, which is what I said. Argumentative fucks. Oh, this is brilliant I just about spit water all over my computer screen... This has gotta be one of, if not the best quote I have ever seen here
|
|
|
Win a FREE Membership!
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
