AR Barrel Length

[Sgt.K]

You could use a Thicker crush washer to gain that .1

You'd need a hell of a crush washer to get .1" - that's over 3/32, or more than a 1/16th and a half.

I'm not ATF, so my opinion is worth what you're paying for it here, but if I measure something (say a barrel) and the end of that something is past the line at the end of my tape measure, then it's longer than the measurement. IOW, 16.01>16

My 2¢

[knight0334]

Minimum length is 16" flat out even. Under 16" requires a tax stamp, or a muzzle device fully welded or pinned AND blind-welded to bring you to 16" or more.

However, it is recommended that you be a noticeable measurement over 16" because the lawman in question's measuring device may measure 16 real inches as 15-15/16". ..yes, not all measuring devices are made equally.

[39flathead]

^^^^This, its 16", not a hair over...

[Eod1]

I tell you what. Make it 16.5 inches and no matter who measures it, it will meet the requirements of any fed no matter what measuring device out there. I use 16 on my barrel ,I feel comfortable arguing that in court.

[NathanB]

I stand corrected. my apologies.

[Eod1]

If you want to know the correct way to measure your barrel. Close the bolt ,put a dowel rod down barrel. It will stop at the closed bolt face. Where it comes out mark it. Pull it, and measure. That is how BATFE will measure it.

[Bang]

din't work....

[Sgt.K]

Women have had a problem with figuring distance and length since the dawn of time. Primarily because men have always told them that this is 12 inches:

[ianb1116]

Only thing I can add to the advice is that you can also attach the break with high temperature silver solder. Easier and nicer looking than welding.

But, Why would you want a short barrel and a long muzzle break? A .223 loses a lot of velocity under 16 inches. A 10 inch barrel will be 300 fps slower and that is significant performance wise. And there is the issue with the orange fireball coming out the end.

Depending on the barrel contour you are not likely to save any weight. I would personally go longest barrel and shortest break.

No one uses high temp silver solder as it dumps way too much heat into the barrel . There is a reason why the Pin and Weld has become industry standard.

Additionally, OP did not specify an AR in .223/5.56. He may be wanting to do this to a .300BO which excels in SBR's.

My understanding is this: you must use a hardened steel pin welded in place in such a way that no amount of force will remove said muzzle device without first destroying the barrel.

As what Knight said, the law is 16" flat.

As for those that suggested using a second crush washer, I would advise against that. You only have so much exposed threads at the muzzle to cut into. The closer you are to the end of the barrel, the higher the likelihood of you destroying said barrel. My recommendation is to us a device, such as the BCM A2X or the likes to acheive the desired length (assuming you're pinning a 14.5" barrel).

Most regulation barrels from the factory come as 16.1".

[knight0334]

Only thing I can add to the advice is that you can also attach the break with high temperature silver solder. Easier and nicer looking than welding.

But, Why would you want a short barrel and a long muzzle break? A .223 loses a lot of velocity under 16 inches. A 10 inch barrel will be 300 fps slower and that is significant performance wise. And there is the issue with the orange fireball coming out the end.

Depending on the barrel contour you are not likely to save any weight. I would personally go longest barrel and shortest break.

The ATF has already ruled against high-temp silver solder when using barrels less than 16" and muzzle devices to keep the firearm as Title 1.

A sub-16" barrel + muzzle device must be fully welded or blind pinned + pins welded over.