308 barrel length

[Merc1138]

Did someone say "dinosaur"?


Just as silly as some salesguy trying to tell the OP that 18" bbl is somehow "ideal" with no context.

I'm no expert but maybe they were suggesting an 18" barrel for a semi-auto ar type platform. Like so many others said not good for bolt action

That doesn't make any sense either...

[Josh3239]

Just to play the devil's advocate...

For the average shooter, an 18" .308 barrel might actually be ideal. How many actually manage to shoot beyond 500 yards? An 18" should burn the powder load, so no ginormous fireball. A shorter barrel-- all else being equal and prior to considering wind-- is going to be more accurate than a longer barrel. You can have a heavier barrel that's not going to be as ungainly as a longer barrel of the same profile.

Your not wrong, but the key word is ideal. And since no situation like minus 500 yards appears to have been stated, the idea that an 18'' barrel is ideal for a 308 because anything longer is inefficient is fallacious. Even if the stated purpose was 300 yards, why would an 18'' barrel be more ideal than a 16'' or a 20''? There are no shortage of guys on the 100 yard line rocking 22''-24'' 308 bolt guns, is that less ideal? An 18'' is capable and with thick barrel it'll be more stiff, but that isn't the issue.

[ar15barrels]

So much fail.

[ExtremeX]

Sure, but you would need a primary arms red dot. None of those dinosaur scopes can see that far.

Did someone say "dinosaur"?


Just as silly as some salesguy trying to tell the OP that 18" bbl is somehow "ideal" with no context.

That doesn't make any sense either...

I watched that entire video... and I watched it though my primary arms RDS...

The video had a really deep blue tint to it... boom boom acka lacka boom

[JTROKS]

Optimum barrel length depends on what gunpowder and bullet weight is being used.

[Pauliedad]

Was measuring FPS last weekend to validate some of my reloads. Also happened to be at a range that went out to 954 yards so regardless of whatever else is said here, I was having some FUN.

Set up the chrono and shot groups at 200 yards.
Rem 700 SPS with heavy 20" barrel was shooting 2500 to 2540 fps. Same load in an LR308 26" bull barrel was shooting 2600 to 2650 fps.
Groups were identical at 200 yards but then again the 700 has a nice trigger and the LR doesn't For me, the difference started to show up at 4-500 yards. Getting on to steel beyond 500 was still consistent with the longer barrel/ higher velocity but got tougher with the short barrel.
So my answer would be
"Depends on what you want to do with said rifle"
For 1-200 yards which is typical for my area's public ranges either of those barrels guns will give me something to work on. If I'm humping said gun all around heck, an AK would be fun.

[tanks]

...

And, WTF is all this 1:10" twist crap in a .308. 1:12" is what you want with a full size barrel.

A lot of the heavier non-lead bullets (copper or brass) are longer and need a faster twist to stabilize.

[JMP]

Maybe for little princess bullets. Real bullets do better with 1:10

If you want to do better with heavier bullets in 30 cal, you should step up to a 30-06 or .300WM, etc.

This one is even better. I'm not saying 18 is the way to go but, it works. Mine is 23" 1:11.25

With a shorter barrel, you will want a bit faster twist because the rotational inertia that stabalizes a rifle projectile in flight is more commonly determined as a function of time, not length of rotation. 1:12" is spinning faster at 3000fps that a 1:10" at 2000fps.

The 1:11.25" twist is the most common; it is not a bad rate, but it has been perpetuated by decades of rifling mythology.

A lot of the heavier non-lead bullets (copper or brass) are longer and need a faster twist to stabilize.

That is the one exception where you'd want a faster twist for stabilization, but you'd use these for areas that prohibit lead. In .30 cal, monolithic bullets do not exhibit a significant increase in performance over lead jacketed. Moreover, this is mitigated because you will need to use a LIGHTER bullet with a monolithic bullet compared to a lead jacketed bullet since copper and an alloy of copper and zinc is almost half as dense as lead, so the lighter bullet occupies quite a bit of space. Now, the slower twist often gains the edge when you have replace the lead bullet with a monolithic bullet that occupies the same volume.

[Shakey]

With a shorter barrel, you will want a bit faster twist because the rotational inertia that stabalizes a rifle projectile in flight is more commonly determined as a function of time, not length of rotation. 1:12" is spinning faster at 3000fps that a 1:10" at 2000fps.

Why are you so tied to 1:12 as "best"? Have you seen the stability numbers for bullets like:
Berger 155.5
Berger 185 Hybrid
Sierra 190SMK
any of the new Sierra tipped bullets
any of the Hornady Amax bullets

You don't have to be shooting 200+ grain bullets to have stability problems with a 1:12 twist, particularly under "bad" atmospheric conditions (sea level, cold, low speed). A lot of the new VLD/Hybrid/etc bullets can have stability issues at 1:12, which is why the bullet manufacturers recommend 1:11 or 1:10 for the new bullets. Heck, John Whidden uses 1:10 in his Palma gun and I think we can all agree that he knows a thing or two about shooting a 308.

[milotrain]

Why are you so tied to 1:12 as "best"? Have you seen the stability numbers for bullets like:
Berger 155.5
Berger 185 Hybrid
Sierra 190SMK
any of the new Sierra tipped bullets
any of the Hornady Amax bullets

You don't have to be shooting 200+ grain bullets to have stability problems with a 1:12 twist, particularly under "bad" atmospheric conditions (sea level, cold, low speed). A lot of the new VLD/Hybrid/etc bullets can have stability issues at 1:12, which is why the bullet manufacturers recommend 1:11 or 1:10 for the new bullets. Heck, John Whidden uses 1:10 in his Palma gun and I think we can all agree that he knows a thing or two about shooting a 308.

I don't think he is saying "best" but I might be wrong. The 155.5 has to be going below 2600 FPS to not stabilize in a 1:12. Or it has to be arctic. You know you aren't supposed to use cream of wheat as a powder right? It's just for fire-forming.

The 185 is indeed on edge, but if you get it moving you should be ok, except in humid winter matches at sea level.

[ktmguy]

If I could I would pull the 16 inch barrel off my (308) scar 17 and I'd put on the 13 inch barrel I really want and at the distances I shoot the hogs won't know the difference. But thats never happening in this great state.

[Shakey]

I don't think he is saying "best" but I might be wrong. The 155.5 has to be going below 2600 FPS to not stabilize in a 1:12. Or it has to be arctic. You know you aren't supposed to use cream of wheat as a powder right? It's just for fire-forming.

Ha! Man, that explains so many of my issues...

The 185 is indeed on edge, but if you get it moving you should be ok, except in humid winter matches at sea level.

Like, say, Sac Valley between November and March?

My point, and disagreement with JMP, is that you PROBABLY will not have problems with 1:12 but you will DEFINITELY not have problems with 1:11 or 1:10, so why go with 1:12 when the cost is the same and there is no* downside?

*Okay, okay, there MIGHT be a downside if you are shooting really old military ammunition. But if you are doing that then you need to start talking about 0.299 bores and other stuff that, like parachute pants and Vanilla Ice, we left behind in the early 90s.

[milotrain]

My point, and disagreement with JMP, is that you PROBABLY will not have problems with 1:12 but you will DEFINITELY not have problems with 1:11 or 1:10, so why go with 1:12 when the cost is the same and there is no* downside?

[highpower790]

IM willing to bet the majority of those with the M14/M1A don't have 1/12 twist barrel,but I do, just for the reason of being able to shoot accurately with bullets 125gr to 175gr.

[Shakey]

I love this idea. "Sorry guys, I'd like to go shooting tomorrow but my barrel won't work in cold weather." Combine that with "my powder is too temperature sensitive" for hot days and you have equipment-related excuses for not shooting when it is too cold or too hot!