.308 20" vs 26" barrel
- Thread starter jgo296
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Ridgerunner665
Member
No more than 250 fps or so...22 inches is the optimum length for a 308.
Rock River makes a 308 AR-10 now?
Well I don't have any experience with 308 Win. gas operated rifles, but I do know that a longer barrel will give you greater velocity. The shorter barrel would be more handy.
I imagine a 26" barrel on an AR-10 would be quite a handful.
Well I don't have any experience with 308 Win. gas operated rifles, but I do know that a longer barrel will give you greater velocity. The shorter barrel would be more handy.
I imagine a 26" barrel on an AR-10 would be quite a handful.
Beagle-zebub
Member
Six more inches of barrel should lead to it being a lot quieter, too. Muzzle-flash would be diminished, but that might not be an issue in the first place.
The .308 is pretty efficient and does pretty well at 20" There have been tests that have shown less than 100fps between 24" and 20". Individual loads and guns will vary of course.
To me 20" is about right for a .308. If I need a longer barrel I want a cartridge with more powder.
To me 20" is about right for a .308. If I need a longer barrel I want a cartridge with more powder.
if you plan to shoot long range and if you're only going to shoot it from a bench or prone, go with the longer barrel.
if it's going to be a 'practical' rifle and you're going to wander around with it on a sling, or shoot from any non-prone, non-bench position, definitely go with the shorter barrel.
2.5lb is a lot of weight. i'll leave you to do the math to see how much 2.5lb feels like on the end of a 20" lever.
one more consideration is that 26" is right on the borderline where people start digging the muzzle in the dirt. high temps, lack of hydration, something else on your mind, a barrel sticking way out past your bag/rest... it'll happen.
if it's going to be a 'practical' rifle and you're going to wander around with it on a sling, or shoot from any non-prone, non-bench position, definitely go with the shorter barrel.
2.5lb is a lot of weight. i'll leave you to do the math to see how much 2.5lb feels like on the end of a 20" lever.
one more consideration is that 26" is right on the borderline where people start digging the muzzle in the dirt. high temps, lack of hydration, something else on your mind, a barrel sticking way out past your bag/rest... it'll happen.
Ridgerunner665
Member
That would depend on the powder burn rate...
4 inches longer could very well be worse than 2 inches shorter if the powder used has a faster burn rate...
On the other hand, with slower powders...2 inches shorter could be worse than 4 inches longer...
Confused yet?
Ridgerunner665
Member
Little to none...the 308 does not need a long barrel.
yeah. so what powder have you shot that results in lower MV on a 26" barrel than a 20-22" barrel? or even, what reasonable 308 load in theory would produce those results?
jgo, the longer the barrel, the higher the MV. The higher the MV, the farther your bullet will go before dropping subsonic at which point, accuracy degrades noticeably.
Ridgerunner665
Member
38 grains of AA2495 (very fast powder for a 308) under a 180 bullet gets 2368 fps from my 22 inch barrel...it only gets 2327 from my 24 inch barrel.....when using fast powders...the pressure can and does start dropping before the bullet leaves the barrel...if the barrel is too long...and a 308 does not need a long barrel.
Ridgerunner665
Member
40 grains of Reloder 15 (a slower powder) gets 2362 fps from the 22 inch barrel...
2412 fps from the 24 inch barrel
Those are with 190 grain bullets.
2412 fps from the 24 inch barrel
Those are with 190 grain bullets.
Ridgerunner665
Member
Any more stupid questions?
rangerruck
Member
anywhere from 250 to 300 fps, may not mean much out to 300 yds, but after that, you will see a large diff in the trajectory.
Grump
Member
So, you're asking us to thing about which type of worse is worse?
Unfair.
By the way, I'm more like I am now than I was when I started reading this thread.
Sunray
Member
"...Any more stupid questions?..." Why does Budweiser think rice belongs in a beer recipe? You asked.
"...There have been tests that have showing..." 100fps loss of velocity per inch of barrel length too.
"...what would you gain in moving from a 20" to a 26" barrel..." Some velocity, but less 'handiness' of the rifle. Every handle an M1A? It has a 22" barrel without a lot of 'handiness'.
IMR4064 with a 165 grain hunting bullet and 168 or 175 grain match bullets. 190 grain bullets work best out of a .300 magnum.
"...There have been tests that have showing..." 100fps loss of velocity per inch of barrel length too.
"...what would you gain in moving from a 20" to a 26" barrel..." Some velocity, but less 'handiness' of the rifle. Every handle an M1A? It has a 22" barrel without a lot of 'handiness'.
IMR4064 with a 165 grain hunting bullet and 168 or 175 grain match bullets. 190 grain bullets work best out of a .300 magnum.
xringer3
Member
If you're a reloader, you're gonna have to try the different powders and bullets to get your best load. I've got a 700LTR with the 20 inch barrel and was shooting right with the guys with the longer barrel robars at 400 and 500 yards. I've not shot it any further than that. I've taken alot of deer inside 300 with this one and it's very handy.
I once had a short 20inch barrel 243 that after trying different powders, found a load with a 95grain ballistic tip that chronographed an average of 3120fps. The book rated the load at around 3000 and other rifles we tried the same load in with longer barrels wouldn't get as much velocity as my short barrel.
Find the right powder combination with your bullet and you'll get the same velocity or close as the longer barrel in most cases.
I once had a short 20inch barrel 243 that after trying different powders, found a load with a 95grain ballistic tip that chronographed an average of 3120fps. The book rated the load at around 3000 and other rifles we tried the same load in with longer barrels wouldn't get as much velocity as my short barrel.
Find the right powder combination with your bullet and you'll get the same velocity or close as the longer barrel in most cases.
Ridgerunner665
Member
Guys...I want to apologize for the "Any more stupid questions" comment...it was late and I was tired...and I get agitated when I sense somebody that is trying to say I don't know what I'm talking about.
I don't know it all, thats true, but I have learned a few things in the past 25 years of reloading and shooting.
Most precision shooters (myself included) prefer stainless barrels...the throat lasts longer.
I don't know it all, thats true, but I have learned a few things in the past 25 years of reloading and shooting.
Most precision shooters (myself included) prefer stainless barrels...the throat lasts longer.
Ridgerunner665
Member
Sunray,
190 grain bullets also work really good in a 308 when you are more worried about penetration than trajectory...Like when you are hunting bear in thick cover.
190 grain bullets also work really good in a 308 when you are more worried about penetration than trajectory...Like when you are hunting bear in thick cover.
rbernie
Contributing Member
Twist rate, groove/land configuration, throat condition, fouling, and a myriad of other factors contribute to a given barrel's ability to achieve a certain velocity with a specific load. Unless you're comparing two identical rifles (save for barrel length) from the same production run for the barrel - you're comparing apples to tangerines.
As a general rule, you will continue to gain velocity well past 26" in most any rifle chambering. However, the differences will be diminishing, and in exchange for a longer barrel and incremental velocity gains comes a definite decrease in rifle portability and a very likely decrease in overall accuracy.
Shorter barrels of a given contour from a given manufacturer are GENERALLY more accurate than longer but otherwise identical barrels. Longer barrels from a given manufacturer are GENERALLY faster than shorter ones.
In 308, I have seen experiments that indicated that the return on length past 16" is somewhere between 25fps and 40fps per inch.
Many folk that shoot 308 at extended distances seem to feel that 24" in a heavy contour (for stiffness) is a good length. It's not really useful for offhand shooting, though. For offhand shooting, most folk seem to prefer a 20" barrel and sacrifice a little velocity loss in exchange for better handling in the field.
It all depends on what you want to do.
GarandOwner
Member
20" was tested to be the "best" length for .308, as far as best accuracy goes. (Though you wont see much difference in accuracy between the lengths, especially if you are an average shooter and dont use reloads) The longer barrels average faster velocities thus increasing your range. I assume you are just going to use this for target shooting, so I would recomend the 22"
RugerOldArmy
Member
I dunno about the advice given in this thread. It seems self evident that if you look to .308 Win in competition, longer barrels are in play. Especially F-Class and Palma.
Wishful thinking?
Wishful thinking?
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