16" AR 10 vs 18" AR 10

[Shadowstalker]

I'm looking for a little advice, I'm going to buy an AR-10 and I was going to get a lesser quality (PSA, DPMS, etc..)18", but they are a little harder to find. Then I started considering a more expensive (Sig) with a 16". What are your thoughts from an accuracy standpoint? I plan to shoot this from 200-800 yes a lot. I have other AR-15's but this will be my first AR-10. I'm not overly fond of dropping 2200 on a Sig, but I don't want to buy a 750 PSA and load it up with gear (trigger, stock, etc...). I guess it really boils down to what has Sig owners shot their 16" barrels out to accurately.

Thanks for the advice and help

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[slimmer13]

Barrel length doesn't give accuracy, it gives velocity. So plug some numbers into a ballistic calculator based on average velocities out of different length barrels. Where the bullet goes subsonic is your max effective range.

Barrel length actually diminishes less in .308 per inch lost than most other cartridges.

 

[Boboclown]

IMHO at 2 grand I'd be looking at other options instead of Sig.

That being said, in general it will be supersonic out to 800 yards even with a 16" barrel.

 

[clearconscience]

When I built my AR10 for hunting I looked at this same issue, there wasn't enough difference for a 308 between a 16 and 20 to make me buy a longer barrel.
I went with the 16" for ease of moving through the sticks

 

[Squidly]

For a .308 (7.62 x 51), go big or go home. If I want a short, handy, manuverable carbine, an AR 10 is not it. Mine have 20" barrels.

 

[hatchj]

I've been looking into the same thing ballistics are so similar between 16-20, I've pretty much decided to go 16 and run it suppressed. That way it's not too unwieldy.

 

[USMC1911]

Imo a bit more info on what the intended use will be could helpful. Bench only shooting or going to be hauled around in the woods.

 

[KKG]

If you are looking for a Rifle to shoot off the Bench, then get the longest barrel you can. You can then get a Combat/Hunting length upper if you decide to need one. That's about the ONLY advantage the AR style platform offers.

 

[P7M13]

Barrel length doesn't give accuracy, it gives velocity. So plug some numbers into a ballistic calculator based on average velocities out of different length barrels. Where the bullet goes subsonic is your max effective range.
Barrel length actually diminishes less in .308 per inch lost than most other cartridges.

^^ THIS ^^

Longer barrel will also give you a longer gas system, which significantly reduces pressure on the bolt and the bolt velocity. Consequently, your cycle rate is lower.
Another factor to consider, the report out of an 18" barrel is quieter than that out of a 16".
I have 16" and 18" barrels in both AR15 and AR10. I prefer the 18" units.

 

[FireArm]

The Sig is worth every penny. My 2 cents

 

[Member 5605]

Find the transonic line....

May limit your 800y engagements.

 

[Kruel J]

Length isn't everything. Even with gun barrels.

I successfully and repeatedly hit 800 with an 18" barrel chambered in 5.56. True story.

 

[Sandaholic]

I would not spend $2200 on a 716. Not that its a bad rifle I have no experience with it. I would just build my own. Build it exactly how I want it.

A quick search shows the 716 may be picky on ammo or you may just need to hope for luck of the draw. Doesn't look like they are SUB MOA for all comers.

I really think accuracy is in the barrel and the load. So if you spend $2200 and find it is 1.5 MOA at best.......seems like you'll get the joy of buying another barrel. Or sending it down the road. Meanwhile if you build it there are a few barrel makers (and rifle manufacturers for that matter) that guarantee MOA or better.

So not hating on the SIG, but it would not be my first choice.

 

[Kruel J]

I would not spend $2200 on a 716. Not that its a bad rifle I have no experience with it. I would just build my own. Build it exactly how I want it.

A quick search shows the 716 may be picky on ammo or you may just need to hope for luck of the draw. Doesn't look like they are SUB MOA for all comers.

I really think accuracy is in the barrel and the load. So if you spend $2200 and find it is 1.5 MOA at best.......seems like you'll get the joy of buying another barrel. Or sending it down the road. Meanwhile if you build it there are a few barrel makers (and rifle manufacturers for that matter) that guarantee MOA or better.

So not hating on the SIG, but it would not be my first choice.

Looked at a Sig very seriously about a year ago. I passed on it.

 

[Boboclown]

IMHO, if going for a piston .308 AR specifically, options like the PWS and Ruger would be better.

But as for .308 ARs in general, either build your own or look at the other DI options. Such as the Armalite AR10As (the As specicially, as the B model uses their own magazines no point in that for an AR).

 

[American123]

I bought the lightweight mlok 18inch PSA build.

I haven't shot it enough yet to be able to make a claim about accuracy. It appeared from the data I researched online the velocity difference between 18 and 20 was nominal and the lightweight mlok helps keep it manageable and not simply a "bench rifle"

 

[SA Shooter]

I knew going into my .308/7.62x51 purchase that I was not going to do a lot, if any, long range shooting out past 600 yards.

Rather I wanted power, medium range accuracy and portability. Also, having another piston design was on my list.

The 16" barrel length of my Ruger SR762 does very nicely, thank you.

 

[Mr Smith]

Do you want it to be semi auto, or would a bolt gun work for you in an AR style platform?

I ask because Ruger makes the "ruger precision rifle" in .308 win, 6mm creedmoor, and 6.5 creedmoor

It also takes DPMS style AR308 magazines. it's basically a bolt action version of the DPMS AR308

 

[B5Ben]

The PSA's are well worth their price, even if you end up getting a precision barrel for it later. I have two. One 18" in 308 and one 20" in 6.5CM and both are great. The 308 rings steel at 550 with no issues. I haven't got much time with my 6.5 but so far no complaints. Just remember that there isn't a standard on the AR-10's like there is for AR-15's.

 

[11Charlie]

I went 18" on mine that I had custom built. Kinda wish I would have gone 16"! By the time I add a can on the end it is going to be difficult to hunt with, but I will do it.