I am interested in purchasing a .308 Win SPS tactical with 20" barrel. What can I expect for muzzle blast / noise / flash from the short 20" barrel in comparison with a .308 win in a 24" or 26" barrel. Any other 'negatives' or issues I should be aware of before deciding on the purchase of a 20" barreled 308 Win ? The rifle will be used for target gongs out to 600 yards + and some hunting out to 400 yards or so. Interested in shooting 165 to 180 grains bullets.
Muzzle blast from 20" barrel 308 Win ?
- Thread starter 17 Ultra Mag
- Start date
A bit of lost velocity and a bit more blast. Not near as much blast as a muzzle break though, really it's not a big deal. You will lose about 25-40 fps/inch of barrel so around 100-150fps less in a 20" than you may get in a 24".
I posted the following comments in a past similar thread:
FACT: a 24" lightweight barrel will NOT necessarily be more accurate,than a 16" medium or heavy barrel. There's more barrel "whip" (vibrations) in longer,thinner barrels. Therefore longer is NOT always better. BTW,take your 24" thin barrel and cut it down to 18 or 16",and you've just made it stronger and less prone to that "whip" and therefore MORE accurate.
Regarding velocity,there is on average only 20 fps (+/-) loss per 1" of barrel length with a .308. Average .308 Muzzle Velocities (MV) are between 2500 - 2900fps (standard loads). Therefore,as Chuck Hawks states:
"For rifles with muzzle velocities in the 2501-3000 fps range,the change in velocity for each 1" change in barrel length is 20 fps."
Magnum calibers or calibers with higher inherent velocities have a bit more loss in velocity per 1" of barrel loss.
"For rifles with muzzle velocities in the 3001-3500 fps range,the change in velocity for each 1" change in barrel length is 30 fps. For rifles with muzzle velocities in the 3501-4000 fps range,the change in velocity for each 1" change in barrel length is 40 fps. "
"According to Gurney,who reports having routinely engaged steel targets as far out as 1,000 yards during testing,the .308 Win. cartridge is one of the least “sensitive” to reduced barrel length." (taken from the first link below)
http://www.americanrifleman.org/arti...cout-review-2/
http://www.youtube.com/watch?v=RFhM0NHsYLk (check out around the 39 second mark)
http://www.tacticaloperations.com/SWATbarrel/
http://www.chuckhawks.com/rifle_barrel.htm
FACT: a 24" lightweight barrel will NOT necessarily be more accurate,than a 16" medium or heavy barrel. There's more barrel "whip" (vibrations) in longer,thinner barrels. Therefore longer is NOT always better. BTW,take your 24" thin barrel and cut it down to 18 or 16",and you've just made it stronger and less prone to that "whip" and therefore MORE accurate.
Regarding velocity,there is on average only 20 fps (+/-) loss per 1" of barrel length with a .308. Average .308 Muzzle Velocities (MV) are between 2500 - 2900fps (standard loads). Therefore,as Chuck Hawks states:
"For rifles with muzzle velocities in the 2501-3000 fps range,the change in velocity for each 1" change in barrel length is 20 fps."
Magnum calibers or calibers with higher inherent velocities have a bit more loss in velocity per 1" of barrel loss.
"For rifles with muzzle velocities in the 3001-3500 fps range,the change in velocity for each 1" change in barrel length is 30 fps. For rifles with muzzle velocities in the 3501-4000 fps range,the change in velocity for each 1" change in barrel length is 40 fps. "
"According to Gurney,who reports having routinely engaged steel targets as far out as 1,000 yards during testing,the .308 Win. cartridge is one of the least “sensitive” to reduced barrel length." (taken from the first link below)
http://www.americanrifleman.org/arti...cout-review-2/
http://www.youtube.com/watch?v=RFhM0NHsYLk (check out around the 39 second mark)
http://www.tacticaloperations.com/SWATbarrel/
http://www.chuckhawks.com/rifle_barrel.htm
ninepointer
CGN frequent flyer
- Location
- Central Ontario
Ditto and Ditto. My .308 has a 19.5" bbl and its blast is no different than my other centre-fires. Also groups as well as my 22" lighweight .270 bbl.
I shoot a braked 20" barrel on my H&R Ultra .308... the blast and noise are no problem for me (the shooter)... but there is some lateral exhaust for shooters at range stations to the left and right, due to the brake... I make sure that there is some buffer space laterally when I am shooting.
Hornady engineer states on the video @ their website that the 308 superformance ammo will loose only 13-15 fps per inch. Having in mind that the 150 gr loads are supposed to do 3000 fps in 24" barrel, 50-60 fps velocity loss in the 20" barrel shouldn't matter that much (if at all)...
I find that the muzzle blast and the flash depend on the ammo you use. I've had quite a blast with the 308 MFS FMJs shot from a 20" barrel (with no flash hider).
I find that the muzzle blast and the flash depend on the ammo you use. I've had quite a blast with the 308 MFS FMJs shot from a 20" barrel (with no flash hider).
Northman999
CGN Ultra frequent flyer
- Location
- Southern Yukon
I've hunted for years with a 18.5" barrelled rem 600. Muzzle blast is no big deal at all.
However muzzle velocity is noticeably less than longer barrels in my experience. I've done up a batch of handloads (45.0gr IMR 4895, 165gr SST, CCI #200, Win brass) and from 22" bbl rifles I was getting 2760 fps, and from my 18.5" rifle I was getting 2590 fps. So that's 170 fps difference, not huge, but that's still 48 fps less per inch, which is much more than some people claim the velicity loss is.
However muzzle velocity is noticeably less than longer barrels in my experience. I've done up a batch of handloads (45.0gr IMR 4895, 165gr SST, CCI #200, Win brass) and from 22" bbl rifles I was getting 2760 fps, and from my 18.5" rifle I was getting 2590 fps. So that's 170 fps difference, not huge, but that's still 48 fps less per inch, which is much more than some people claim the velicity loss is.
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Had a 742 carbine with 18.5 inch barrel in .308. I found the gun to be a little louder than a standard length but it seemed sharper with the lighter bullets e.g., 150 grain, not really objectionable. The only way to truly know velocity loss is a chronograph, too many variables in guns and loads.
Northman999
CGN Ultra frequent flyer
- Location
- Southern Yukon
Could definitely be the case.
It may also be that around 20" is ideal for a .308 with IMR 4895, with shorter barrels losing velocity noticeably, and longer barrels not really gaining much with that powder.
I was thinking pf purchasing one of those a few months back. Let me know how you like it.
Rocket Surgery
CGN Ultra frequent flyer
My 18 inch gunsite scout 308 rifle makes quite a big blast, and is a lot louder than my m305 with a 22 inch barrel. It's more bark than bite though, the thing barely kicks at all. I have had a lot of people comment on my muzzle flashes and the amount of noise my gun makes.
I have one of the .308 Remingtons with the 20" barrel. I don't notice any more "muzzle blast" out of it than I do my longer barrels. What I do notice is a handy lenth and a gun that will put cheap Winchester grey box 180's into a 1" circle at 100 yards all day. If you are looking at shooting 400 yards I would think that the accuracy potential of the gun is more important than a little more noise. Also with the heavy barrel that extra weight out front means there is very little muzzle jump and it's a lot easier to stay on the target.
