18.6" Barrels for AR15

Some guys are 300 pounds of muscle, some others are 120 pounds of bones.
Some guys sit at the bench to shoot 300 rounds an hour, others carry their rifle all day in a 3-guns or cqb match and shoot 90 rounds a day.

There isn't going to be one single perfect barrel profile for everyone. Even for the same person multiple barrels/uppers can make sense.
 
homer76 said:
...and I don't care to hear you explain advances in metallurgy. I have a bit of experience with the AR-15 and know through experience about shifting point of impact as barrels heat up. If the small amount of weight difference between a pencil and government profile barrel bothers you do a few extra arm curls.
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Or start by trying a pencil barrel manufactured in this century before spreading your frozen beliefs.

Arm curls... What a clown.
 
Skeet Mcgee said:
Absolutely agree the AR 15 will function reliably with an 18" (or 18.6 as is the case here). The ability to run a 12" handguard and still be able to cover the gas block under a free float tube with intermediate also saves weight out front.

I and others running 18" barrels with rifle length gas systems have experienced short stroking on cold days with this setup. The "pressure chamber" created by a longer port placement delivers lower pressures to the carrier which can induce "short stroke" failures with weak ammo in cold environments or with fouled guns. Having higher pressure combined with longer secondary dwell phase (bullet past the port) gives you the the extra pressure needed to reliably run the system in less than perfect situations ie. It runs more reliably. This system allows you to take advantage of an adjustable gas block to lessen the pressure if in ideal conditions or to reduce felt recoil during competition, where on a rifle length, if you're not getting enough gas you have to look for alternative solutions such as buffer weights etc.
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Can't argue with your experience, I just haven't seen it, even in cold weather. Agreed that dialing down an over-gassed gun is easier in the field. That being said, opening the gas-port up even a little will give you that condition on +18" rifle-length barrel. (still in the realm of 223/556 of course) Once you've got the gas port opened up you can dial the gun in accordingly.

With regards to weight distribution, I think that's personal preference more than anything else. I like gripping further forward on the rifle, so i'm going to go with a 17/18" handguard. Rifle length gas pushes the block further to the front, making it easier to adjust, which I appreciate.
 
homer76 said:
...and I don't care to hear you explain advances in metallurgy. I have a bit of experience with the AR-15 and know through experience about shifting point of impact as barrels heat up. If the small amount of weight difference between a pencil and government profile barrel bothers you do a few extra arm curls.
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I get so tired of people who immediately start hurling insults at guys that prefer lightweights. He asked what people want and they’ve answered. You’re free to voice your opinion for another option but there is no need to trash talk others.

You do know that a pencil and government profile are the same diameter under the handguards don’t you? It’s only the last few inches towards the muzzle that are thicker and that’s not where you need it.

Molon has some excellent posts on arfcom about lightweights and how they perform. Real world data, not internet conjecture. The groups he achieved are more than acceptable for my needs. If they don’t meet yours than there or more than enough thicker options out there. Pencils, not so much, which is likely why you’re seeing a lot of people asking for them here.

I’d be very interested in a lightweight Norc hammer forged 18.5” 1/8 .223 Wylde with FSB. In fact I’d be interested in people’s experience with the 1/9 lightweights that came on the 20” DA556.
 
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There is a lot of quality 18 inch barrel in the market.

Now the NR status is a 18.6 inch.

Would it be legal to have a 18 inch barrel with a muzzle brake to make it 18.6 inch?

like pinned brake of something
 
charlesquik said:
There is a lot of quality 18 inch barrel in the market.

Now the NR status is a 18.6 inch.

Would it be legal to have a 18 inch barrel with a muzzle brake to make it 18.6 inch?

like pinned brake of something
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One of the first bureaucratic tricks they pull is no say NO to that. Their raison d'etre is to restrict and ban guns.
 
Leg said:
I’d be very interested in a lightweight Norc hammer forged 18.5” 1/8 .223 Wylde with FSB. In fact I’d be interested in people’s experience with the 1/9 lightweights that came on the 20” DA556.
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1.25 MOA on the regular (occasionally better) with 69gr handloads at 100m. Non free float, off bags with a 3-9 cheap scope. Norc trigger. Groups shot with 10 seconds or so between shots. Too dull to do it any other way.
Didn’t have time to really tune the load as I sold the upper.
 
The new rifles in the video also have forends that free-float the barrels in addition to the stress-relieved barrels. That raises the question: how much of the improvment is due to free-floating versus stress relieving?
 
BioPace said:
1.25 MOA on the regular (occasionally better) with 69gr handloads at 100m. Non free float, off bags with a 3-9 cheap scope. Norc trigger. Groups shot with 10 seconds or so between shots. Too dull to do it any other way.
Didn’t have time to really tune the load as I sold the upper.
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Wow! I’m surprised you got rid of it if it performed that well. Cutting one of those down to 18.5” would give you a decent barrel at a great price.
 
Leg said:
Wow! I’m surprised you got rid of it if it performed that well. Cutting one of those down to 18.5” would give you a decent barrel at a great price.
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Well yeah. In hindsight selling it was a bad idea. But buying a 16” rifle I can take to the US seemed like a good idea.
 
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