determining AOL of firearm with brake

When determining the OAL of a firearm for a Form 1, should I include the brake attached to the muzzle or not?

Also, how picky is the ATF over +/- 0.1" for barrel length?

only if permanantly attached.

I suspect if you are 15.99995" barrel length, you are in trouble.

Which is why a lot of barrels get cut to 16 1/4".

Never expect "mercy" or a "tolerance" from the BATFE. It won't surprise me if someday agents are carrying tape measures that show an actual 16" barrel at 15.9".

Fudge on stuff like this at your own risk.

I was filling out Form 1s to make AOWs and the OAL was tough to measure precisely. One of the pistols was a custom-cut barrel. I got the measurements down to the nearest 0.1".

I was not 'fudging'. I was trying to be as accurate as I could, but it the conversion to sixteenths of an inch to decimal concerned me, so I would prefer to round to the nearest 0.1".

My concern is that my Form 1 might say AOL = 22.3" and the actual OAL might be a hair under 22.3".

I was filling out Form 1s to make AOWs and the OAL was tough to measure precisely. One of the pistols was a custom-cut barrel. I got the measurements down to the nearest 0.1".

I was not 'fudging'. I was trying to be as accurate as I could, but it the conversion to sixteenths of an inch to decimal concerned me, so I would prefer to round to the nearest 0.1".

My concern is that my Form 1 might say AOL = 22.3" and the actual OAL might be a hair under 22.3".

When in doubt, round down, not up, better to be long then short.