.308 Barrel Length?

JCooperfan1911 said:

Trying to decide on the barrel length for my next .308 rifle. Either 16.5” threaded for a flash hider or liner compensator, OR a standard 18” barrel.

Both would be almost identical in length when you factor in the muzzle attachment on the 16.5” bbl but would the longer 18” bare barrel reduce flash/blast as much as the 16.5” with hider or comp?

Thank you.

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An 18" Bbl'ed .308 Cal... is already pretty short.

Blast - will already be an issue.

Unless you put a can on it.




GR

16 to 18 inches in .308 with factory loads is simply a bit of a flame thrower.

What kind of gun do you have in mind?

Both will be pretty ferocious. Wife has had two 20 inch barrels on rifles. One a 308 the other a 6.5 Creedmoor. Both bolts. Most factory ammo has a tremendous flash and the blast on the 308 was noticeably worse than a 22 inch barrel. Fussing around with a faster powder and lower charges helped a lot with the 308. Have not screwed around with 6.5 yet.

JCooperfan1911 said:

I have 0 interest in “cans” so what would be the best choice as far as limiting blast and noise?

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On all honesty, either a longer barrel or crafting hand loads specifically for the shorter barrel.

As was stated, the .308 is awfully blasty from anything shorter than 22”. Mine has an 18” barrel and it sure isn’t pleasant at all.

Stay safe.

My 18” 308 AR has a JAL linear comp, and is very pleasant to shoot. Kaw Valley also has a very nice linear comp at a good price.

I find 20" to be plenty of barrel as far as velocity is concerned with a 308. If you want to significantly improve on what you can get with a 20" barrel you need to go 26-28" which is just more than I want. I can live with 22", but always feel it is just unnecessary.

If I were building "MY" perfect 308 I'd start with a 20" barrel. Going shorter doesn't hurt speed as much as a lot of folks think, but below 18" noise does start to become an issue. I have one rifle with an 18" barrel. It's OK, but I don't feel the longer 20" barrel is a handicap and the longer barrel is more pleasant to shoot.

I can't help with anything you screw onto the end of the barrel. But I suppose whatever length you need to start with to get around 20" overall would be a good idea. The rifle I have with the 18" barrel is threaded for a can. I suppose that if I ever buy one I'd like it better.

Winchester and the Army thought 22" was about right. I thought 28" was good, largely because that was the longest I could get before the price went up with added length over that.

What will a shorter barrel do for you?

How about 26”?

JCooperfan1911 said:

This will be for a scout style rifle.

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Well I should have know that, considering your chosen forum handle

JCooperfan1911 said:

Thanks


Not what I’m going after, chief.

This will be for a scout style rifle.

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This is a 16" Bbl.... but I haven't shot one.


GR

JCooperfan1911 said:

This will be for a scout style rifle.

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From my own experience, I vote for the 18" barrel with no muzzle device. Unless you just want to add one later, which is always an option.

If you happen to be looking into the Ruger Gunsite Scouts, or more recently named Ruger Scouts, the early versions came with barrels actually longer than listed on the spec sheet by Ruger. Both the early 16.5" and 18" GSRs* actually came with barrels at 17.25" and 18.75" long (measured with muzzle device removed).

My particular GSR was bought in early 2013 with the spec'd 16.5" barrel, but if you slide a cleaning rod down the bore with the bolt closed, make a mark on the cleaning rod, then remove that rod and measure . . . 17.25". Flash hider removed, of course.

So, if you did come across an early GSR with 18.75" barrel, it would be dang near the same length barrel as in the Steyr Scout in .308.

For what it's worth, I removed the flash hider on my GSR after the first time I took it out shooting. The few times I've let others fire it, the muzzle blast out of that bare 17.25" barrel is not worse than being beside a 16.x" barreled AR in 5.56 with a muzzle brake being fired.

*Note that Ruger's website currently shows barrel lengths of 16.1" and 18.7". Which pretty much indicates that Ruger makes the new longer scout barrels the same as they did back when they were called 18" barrels. Yet, the 16.1" barrels are certainly shorter than the old 16.5" (actual 17.25") barrels.

I have grown quite fond of 16" barrels on 308 AR10 type rifles. But I am also a NFA stamp collector, so...

I've hunted a fair bit with scout style rifles, and I didn't find barrel length to be as important to 'handiness' as much as receiver shape, stock fit, and rifle balance. A good scout rifle, IMO, should be easy to carry at the balance point and slightly muzzle heavy at the front receiver ring to 'hang' well offhand.

Given that, I'd probably do an 18" with threaded muzzle - just to have threads in case you decide to use a linear comp for extended range sessions.

I have an 18" .308, the answer to blast is faster powders. Muzzle blast is comparable to .223 for me. I have an extra-long A2 birdcage flash hider on it, the kind you get for 14.5" barrels. Recoil is very heavy, but noise/flash are average. H335 is what I'm using, mostly because its what I have on hand. If you don't reload, this won't help.

I've got a 20" bull barrel 308 bolt action and a 24" bull barrel 308 AR and I don't notice any muzzle flash on them. And I don't shoot at night or anything. They both have similar velocity. I shoot a lot of reloads and factory ammo (Nosler match ammo and Federal Power Shock).

mjsdwash said:

I have an 18" .308, the answer to blast is faster powders. Muzzle blast is comparable to .223 for me. I have an extra-long A2 birdcage flash hider on it, the kind you get for 14.5" barrels. Recoil is very heavy, but noise/flash are average. H335 is what I'm using, mostly because its what I have on hand. If you don't reload, this won't help.

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If you were building a hunting rifle...

Why not add 2" of Bbl. (20"), instead of 2" of flash hider to an 18" Bbl.?

One of the nice features of the M1 rifle.

24" Bbl... w/ an OAL of a little over 43".

...like a 22" Bbl'ed bolt rifle, and shorter than the 22" Bbl'ed M1A.




GR

20" is the sweet spot. 22" if you want the ultimate bolt rifle for hunting. 16-18'' is carbine length for combat and patrol rifles. Not optimal for hunting applications. You never said anything about bolt or AR actions unless I missed it. AR's are carbines, pure and simple.

You need to specify the application.

Garandimal said:

If you were building a hunting rifle...

Why not add 2" of Bbl. (20"), instead of 2" of flash hider to an 18" Bbl.?

One of the nice features of the M1 rifle.

24" Bbl... w/ an OAL of a little over 43".

...like a 22" Bbl'ed bolt rifle, and shorter than the 22" Bbl'ed M1A.




GR

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weight. its already too long and front heavy. another 2" and 5 oz, and 10% more recoil, and a bright orange flash isn't worth 80FPS.

I really LIKE long barrels, 22-24 is about rhe shortest ill have on anything besides a dedicated "carbine" type gun.

I have shot plenty of shorter guns, and honestly you need to get down around .223 size, for me ro be able to really tell a difference between a 16 and an 18.
20 seems to be just long enough to make a difference I can detect.

Ive also used linear comps and i like them, they may not reduce the total noise of the shot, but they are helpfull at redirecting it away from the shooter, and more importantly for me, bystanders.
Ive fired a 24" 7mag with brake, rhen bare muzzle, then linear comp, and even compared to the bare muzzle the linear comp offers less blast when sitting at 5 or 7 o'clock from the shooter, and way less than when directly to the sides of the muzzle.

Thus id probably go with a 16.5+ linear comp.

I have a .308 Win bolt gun with an 18.5 inch barrel. (I just measured it.) Perhaps I don't know better but the muzzle blast does not seem excessive to me. Reloading I get respectable velocities (2550 fps with 174 match bullet). I've shot it along side other shooters and haven't heard complaints about it. (Perhaps they're awestruck?)

IMO:

Suppressed: 16"-18"

Unsuppressed: 20"-22"

JCooperfan1911 said:

I have 0 interest in “cans”

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Why not? Have you ever played with them? Most people, once they experience it with a quality can, take the position of "suppress all the things!". I have 71 suppressors that I use on shop demos and personal firearms (not counting the ones that are in jail for customers or for sale). It becomes an addiction for most.