How heavy a barrel for a AR15

[waldo1979]

I'm going to build a AR15 upper looking for accuracy. My first thought was to get the heaviest barrel I could find maybe .936" from the gas block out to the muzzle. Then I started to wounder if all that weight could make the upper receiver flex hurting accuracy.

Anybody have any thoughts? Maybe I should just crack a beer and not worry.

You want a .936" gas block. Yes the upper can flex so get a heavy reciever like a heavy DPMS or something like a Sun Devil (the owner is a good guy and will answer questions if you give him a call). Thicker barrels shoot better. I have a heavy 24" Krieger with a .750 gas block and has seen .936" gas blocks shoot better.

Get a clamp on non-adjustable gas block, as light as possible. Use a gas tube that is at least rifle length. The longer the BCG remains engaged the better. David tubs sells weights that can be placed in the back of the BCG. Les Baers BCG is heavier than most.

Zediker talks about this stuff in his AR builder book:
The New Competitive Ar15: The Ultimate Technical Guide: The Rifle, the Ammunition, the Shooter https://www.amazon.com/dp/1607023997/?tag=accuratescom-20

There are a bunch of Les Baers at our range and one heavy well DPMS that can shoot.

 

[waldo1979]

+1 for WOA varmint contour. Their barrel is .936 gas block and .925 forward of that (I just measured mine).

If balance is a concern, put in a butt-stock weight.

balance with a 24" bull barrel is right in front of mag-well, I put my bipod at the gas block and have no trouble. You'll want a handguard that covers the gasblock free-floated. It'll reduce mirage from the massive heat-sink that is the block...

-Mac

Compass lake built my last Krieger upper but wouldn't mind a WOP upper.

 

[Gappmast]

I would like to get back to my original question, receiver flex. We all agree that a bull barrel reduces barrel flex when the gun is fired. But if the the barrel is to heavy hanging off of the receiver will it cause the receiver to flex. Causing the same problem that you would get with a small diameter barrel?

 

[mac86951]

I would like to get back to my original question, receiver flex. We all agree that a bull barrel reduces barrel flex when the gun is fired. But if the the barrel is to heavy hanging off of the receiver will it cause the receiver to flex. Causing the same problem that you would get with a small diameter barrel?

I'll be honest, I've always used DPMS heavy wall receivers, problems could be attributed to receiver flex, but honestly none that I know of, nor that I've seen. I haven't gotten a chance to see any upper receivers with thin walls.

Mac

 

[akajun]

I would like to get back to my original question, receiver flex. We all agree that a bull barrel reduces barrel flex when the gun is fired. But if the the barrel is to heavy hanging off of the receiver will it cause the receiver to flex. Causing the same problem that you would get with a small diameter barrel?

NO it will not, at least not enough to see on paper, as long as you have a Free float handguard that is.

 

[lloydx2]

NO it will not, at least not enough to see on paper, as long as you have a Free float handguard that is.

 

[lloydx2]

The receiver will flex. Saw some vids that Robert Whitley (6 ar.com) posted some were
It looked like a piece of plastic in slow motion. But that's ok. When you think about it.
The receiver is screwed on to the end of the barrel barrel ext) The bolt more or less floats
in the carrier. That's what makes them so forgiving

 

[Gappmast]

The receiver will flex. Saw some vids that Robert Whitley (6 ar.com) posted some were
It looked like a piece of plastic in slow motion. But that's ok. When you think about it.
The receiver is screwed on to the end of the barrel barrel ext) The bolt more or less floats
in the carrier. That's what makes them so forgiving

That makes a good case for not going to a side charge handle, especially on the left side. That would weaken the receiver even more.