Need some advice - .308 barrel length vs accuracy

Viper1973

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Mar 29, 2013
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I’m looking to purchase a high-end large-frame AR chambered in .308 that will be primarily used for target shooting, hunting and some limited long range precision plinking (800-1000y max). It needs to be light enough to be able to be shot off-hand reasonable well. The gun will eventually be suppressed (once the ATF paroles my can). Ammo will most likely be FGMM 175’s (or equivalent).

I’ve narrowed down my purchase to the gun I want but am having a devil of a time picking which barrel length would get me where I want to be without giving up accuracy. My options are:

16.1” fluted 1:10RH (9lbs unloaded out of box weight)
20” fluted 1:10RH (10.5lbs unloaded out of the box weight)

I’m leaning towards the 16.1” because it’s lighter and will only be about 24.5” when the suppressor is added where to 20” would be almost 29”.

I’m thinking the 20” (or 29”) barrel would be too long (especially suppressed) to be able to meet all of my goals for this rifle and would actually become a handicap and be super nose-heavy.

For extreme long range (1000y+) I have an AXMC that can easily get the job done and for shorter ranges I have a 5.56 AR. My entire goal for this rifle is to bridge the gap between my existing AR and the AXMC without sacrificing accuracy.

Is the 16.1” going to be too short to meet the stated goals? Thoughts? I’m trying to avoid having an AR10 that’s ONLY usable from a bipod or barricade. Am I right in my thinking that a 20” is too much?

Any advice or recommendations are most appreciated.
 
Barrel length is not directly related to accuracy. The accuracy depends on you and the bullet and the rifle. Barrel length is a velocity variable for the most part (and weight). More velocity equals longer ranges which means you could be more accurate further out.

IMHO, an 18” barrel with a good twist (1:10) is a solid choice for a 308 out to 800. It’s a good compromise of weight and velocity.
 
IMHO, an 18” barrel with a good twist (1:10) is a solid choice for a 308 out to 800. It’s a good compromise of weight and velocity.

That is what I was originally considering. After speaking with the manufacturer they no longer offer an 18” variant in the rifle I’m looking at. Supposedly sales weren’t even close to what the other two lengths get and it wasn’t cost effective for them.

Both of their barrel options are match barrels, same twist and guaranteed sub-MOA at 100y (their testing criteria).

I’m just concerned that going 16” may short-change me in the long run :(
 
Seekins SP10 comes with an 18"

That's a 9" tbac ultra9.
 

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No. The butt stock has some weight to it which helps balance it out. I'll get some weights for you tomorrow.

Thanks so much... that would be awesome!

I have to make up my mind by Wednesday afternoon if I want to have it by Christmas ?
Since there are no stocking dealers around here it makes it even more difficult to decide since I can’t actually handle one directly.

If it makes a difference, the gun I’m trying to decide on is the LWRC REPR MkII. So impressions from any other REPR owners would be appreciated since most probably had to deal with the same decision I am.
 
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Take a look at the Seekins, Larue, LMT, GAP rifles. Or PWS if you want a piston.

I would get a 16".

Was originally considering Larue or GAP but I can justify a several months wait for what is on a basic level just an up sized AR15. GAP receivers aren’t even made by them, they’re Seekins.

Given the $$$ I’m willing to invest into this, i’d prefer to stick with companies that have a history of doing government contract weapons work and make their own stuff. Given how proprietary large format ARs are if the maker goes under so does your supply of parts and barrels.

I had originally narrowed my choice to the SCAR until I shot a buddy’s... it was probably one of the most non-ergonomic guns I’ve ever shot. I then saw a review of the REPR and it seemed to be a much better solution.
 
I've owned and shot a few different 308 auto loaders in 16". They all had muzzle brakes and were all obnoxious to shoot. Granted the brakes might've been the big part of them not being all that fun. Based off that I don't know if I'd ever own a 16" barreled .308 again. Then again I live in California and a silencer ain't gonna happen for me. I say screw it and get the 16" with the can.
 
Corey4,

You’ve gone above and beyond what I was expecting... you didn’t need to tear your rifle apart. Thank you SO much for taking the time to help me!

You and HossDaniel4 changed my mind to the point where I did some research and saw Frank’s factory tour video which totally changed my impression of the company.

After seeing your setup I made a ton of calls trying to find one of those to see first hand to check out. Totally struck out. Called Seekins again trying to find a dealer. Figured at least maybe they could help me with that.

Got a different person this time who asked me a couple questions. He felt the Military variant would better meet my needs and said that those have to come from MHSA exclusively.

Through sheer luck Mile High had a new SP10M in stock and in FDE (which was one of the things I really liked about the REPR.)

It’s now enroute to my FFL and at about $800 less than what I was preparing to spend.
And... on an additional note.. I owe BCP a huge apology. You were trying to save me a nightmare in the making and I was too stuck on my own way of thinking to see it. I’m sorry.

You guys rock!
 
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Given the $$$ I’m willing to invest into this, i’d prefer to stick with companies that have a history of doing government contract weapons work and make their own stuff. Given how proprietary large format ARs are if the maker goes under so does your supply of parts and barrels.

I had originally narrowed my choice to the SCAR until I shot a buddy’s... it was probably one of the most non-ergonomic guns I’ve ever shot. I then saw a review of the REPR and it seemed to be a much better solution.

The military rifles is my specialty. If that is your direction, I would look (again) at LaRue (wait is not that bad), LMT, Knights, and the new SCAR 20". Much more of a long-range shooter and ergonomical. We just got them in the shop, and are pretty impressive, and will not last long. I personally build off of LMT and Knights and shoot both. They use many interchangeable parts, and both are solid performers. Knights commands a steep premium. Most would say it is worth it. You can spend less with LMT and be very happy as well.
 
Barrel length is not directly related to accuracy. The accuracy depends on you and the bullet and the rifle. Barrel length is a velocity variable for the most part (and weight). More velocity equals longer ranges which means you could be more accurate further out.

IMHO, an 18” barrel with a good twist (1:10) is a solid choice for a 308 out to 800. It’s a good compromise of weight and velocity.

Agreed, shorter barrel will reduce velocity, will not necessarily reduce accuracy.