How much noticeable difference in barrel length in 308?

Woodbeef

Woodbeef

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How big of a difference is there between a 20" and a 24" barrel in 308 for a Tikka Tactical with the 1:11 twist? I know it will effect velocity some,but what about accuracy and distance?
 
It should not affect accuracy.
It will affect velocity.
The effect on trajectory will be irrelevant for known distance target shooting.
Reduced velocity will result in greater wind drift at extended ranges.
 
Most of our tac rifles sport 20 to 22" barrels . ALL are easily 1/2 moa or better shooters and most get shot out to 1000 yards and some like mine , C4Pyros, Glockamaniacs and Blackclouds get shot ALOT at distances greater than the 1000 yards.
We have certainly not had any lacking in velocity or accuracy.
 
alberta tactical rifle said:
At 1 point in time that may have held true, but with the powders of today this is not always the case.
The 22" barrel on my 308 has no problem spitting 190 gr SMKs out the muzzle at 2675 fps. Many are shooting 175 gr Bergers at well over 2700 fps.
Click to expand...

New powders or not, those seem like pretty stout loadings for a .308!? The 190 MK's anyway.
 
There will be no difference in accuracy at all. If you are shooting off a bipod or rest all the time, go with the 24" as adding more weight will make it more comfortable to shoot. The short barrel on the light gun will tend to bark a bit.

The Tik-Tac is as accurate a rifle as you will find in any top end factory gun. I love them.
 
I have got a tactical 308 with 20" barrel and use it for 600+ yard shooting.
Its got a bit more kick then my 26" barrel rifles but its not that bad really.
 
Will the same hold true for other calibres that use slower burning powders ? Specifically, I'm thinking of my .260AI. I have 20" barrels on a .308 and a .223 and absolutely love how they handle. Since both these cartridges use medium burnrate powders, I can see that a shorter barrel won't affect velocity as much. The .260AI favours slightly slower powders. I've got a 26" tube on my rifle and would really like to go shorter.
 
What about muzzle blast on a 20" barrel? I'm not so bothered about recoil but muzzle blast is more of a issue for me. I'm talking .308 Win here.
 
Shorter barrels will give the shooter more blast. The exhaust is closer to the ears and at a higher pressure. 4" of additional barrel (26") can make a huge difference in this.

rhs, yes, a 260AI will be slower the shorter the barrel especially when you get to 20" or less. There doesn't seem to be a huge difference between 26" to 30" (variations between barrels play a larger role) but velocity will start to fall off dramatically as you go towards 20".

pretty good estimate that you will loose 20 to 25fps per inch of barrel below 26".

Both the 223 and 308 really drop speed once you go under 18" of barrel. There are plenty of short barreled military rifles to illustrate this point.

Jerry
 
There is no magic number for velocity loss when cutting a barrel. Its highly dependent on the bullet and powder combination. If the powder is still being all burned up in the shorter barrel (heavy bullet, small amount of fast burning powder), the velocity drop will be negligible. If the powder has not being completely burned in the shorter barrel (light bullet, lots of slow burning powder), the drop can be quite large.

I recently went to a 22" barrel from a 26" barrel in my 308 Win. My 190 SMK + 42.3 Varget load lost a wopping 20 fps. However, my 110 VMAX + 48.0 Varget load lost around 200 fps. Velocity is actually higher in the shorter barrel with my 180 RN + 8.0 Titegroup subsonic load. I have also seen that happen with .22 LR subsonic ammunition in the ZKM 452 with the 28" barrel (velocity is higher in a 16" barrel rifle).
 
rhs said:
Will the same hold true for other calibres that use slower burning powders ? Specifically, I'm thinking of my .260AI. I have 20" barrels on a .308 and a .223 and absolutely love how they handle. Since both these cartridges use medium burnrate powders, I can see that a shorter barrel won't affect velocity as much. The .260AI favours slightly slower powders. I've got a 26" tube on my rifle and would really like to go shorter.
Click to expand...

Each caliber will have its own quirks in this regard.
I have found that larger capacity cases require longer barrels to get the most out of slow burn rate powders.
My 300 Win, and 338 Lapuas I like to see longer barrels than the norm.
The 300s in my experience work better with 27 or 28" barrels and the 338 Lapua I believe requires 28 to 29" of barrel to attain the full potential of what the case and slow owders can deliver.

I burn Vit N550 in my 308 which is a fairly slow powder for the caliber, I have NO unburned powder coming out of the 22" barrel so it must all be burned in the short barrel. Pressures are low and velocity very good.
What can I say???
YMMV
 
Velocity vs barrel lenght

A couple articles on the topic. Experiments with 308, 300 Win Mag and 223. (spaced to break the hyperlink)

308 and 300 Win Mag

ht tp://www.tacticaloperations.com/SWATbarrel/

223

ht tp://www.accuratereloading.com/223sb.html
 
How does the 168 SMK with a mv of 2800fps perform at extended ranges?
Just checked the Sierra ballistics program, and answered my own question. With mv of 2800, the bullet could still be supersonic at 1000m.
 
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