I bought a DD 14.5" barrel and a 2.0 Battle Comp, I know I need to get these pinned  and welded but wanted to know if this combination will be the legal 16" length.

if i'm correct, it's longer than the 1.5, which would have made it legal.

the 1.5 also has a pre-drilled hole, but who the hell needs that LOL. nothing a drill can't fix.

Well that's why I bought the 2.0 it measures 1 3/4" just to be sure. Thing is I actually took them to do the pin and weld and the gunsmith says its a 1/2" short of 16".

Did the smith measure with the bolt in battery, or measured the overall length, including the barrel extension?

I just looked at the site, and I might be wrong. the 2.0 DOES look shorter than the 1.5.

Just went to the website. 2.0 is pretty much the 1.0 but compatible with suppressors. You need the 1.5.  I'm sure someone will take that 2.0 off your hands.

He didn't measure with the bolt in place. He attached the barrel to the upper, put my rail on and screwed on the comp and measured from where the upper and rail meet to the end of the comp and measured 15.5".

Thats not how it works. 16" barrels dont even measure 16" from the receiver. You measure from the extension.
Edit: i thought the 2.0 was long enough but guess its not? Its the same length as a A2 so it would be too short I guess.
Apparently with the 2.0 you will sit 0.20" short

So you think 1.5 will give me the extra length I need.

If your barrel is exact 14.5 and has .600 length threads and the flash hider is 2.0 then you will end up with a 15.9 OAL
and if you add a crush washer you may be at 16.0
A muzzle devise takes away some length when threaded on.
With the bolt group in drop a cleaning rod in the barrel until its against the bolt face, mark the rod with tape at the crown of the barrel, pull it
out and measure the length.

I know it will.. I have the 1.5 on my 14.5 dd barrel

I have a 14.5 BCM upper with a pinned and welded BattleComp 1.5 on it.  I have measured it to be 16".

The 1.5 is the one you need.

Battlecomp 1.5

Your 14.5 barrel must be longer than you think.
A 14.5 barrel and a 1.5 muzzle devise will not make a 16.0 oal as the devise threads over .600 of the barrel so you end up with
15.4 oal and 15.5 with a crush washer.

Interesting, I did not know that (makes complete sense though). Do you have a link to something official showing that to be the prescribed method? I'd love to have that as a reference source.

Seems the "1.5" name refers to usable or "net" length. From the description

ATF made this rule and its the true way to get the length.

I believe you, was just hoping you had a link to that information on their site or some other official site. Makes it easier to quote than saying "I heard it from some guy on the internet". No offense intended, I don't doubt your facts, just looking for a quotable source to show others in the future (off to search the ATF site for the info now).

I see as the true oal of the BC1.5 is probably 2.1 or longer and they call it what it adds to a barrel instead of the real oal.

And easier than I expected, here is the BATF page backing what you said (and Thank You again for the info!).
BATF Barrel measurement procedure

You are faster on the web seach than me
Since I make many barrels and some integral suppressed I know many of the atf rules + it helps to have the fed regs and state regs books at home.

Great responses and information. Exactly what I was expecting from a great forum. Thanks again to everyone.

Edit: sorry misread, thought he was saying a BC 1.5 wouldnt make a 14.5 legal, realized he meant a 1.5" MUzzle device.

:) This is straight from BCM's web site sir :

The BattleComp 1.5 in Black Oxide will fit all barrels with 1/2 x 28 RH standard threads.

The BC1.5 has the same performance as the BC1.0, but the BC1.5 has been extended and pre-drilled for permanent attachment on 14.5" barrels needing 16.1" overall length.


One of the reasons I went with their comp mod 1..

BC 1.5 is the model number..it actually measures just over two inches

My reply was similar, but I realized he was talking about 1.5" long devices in general, not the BC 2.0, which is like 2" long.

The BC 2.0 I purchased is actually 1.75" long.

Yup, the 1.0 and 2.0 are 1.75", which keeps it under 16", as they retain A2 dimensions. With the threads it puts them under 1.5" added to the OAL.

I blind pinned a B.E. Meyers 249F on a 14.5" Cross Machine Tool M4 barrel (it originally was a 16" M4 barrel I had them cut to 14.5") that actually measured an over-all length of 14.625". I'm guessing the barrel manufacturer wanted to give an extra 1/8th inch leeway to guarantee the barrel would meet the 16" rifle barrel length minimum. The 249F measures an OAL of 2.75", and the included washer measured (0.125)

Using a dowel rod on a closed bolt (you can take the bcg's bolt and place it in the barrel's, barrel extension, just make sure the bolts in battery when taking the measurment;) place the dowel down the barrel from the muzzle to the bolt that's still in battery, then mark with a piece of tape where the dowel meets just outside the barrel and just past the barrel crown. See what the dowel measures to; this is your barrel OAL without a muzzle device.

Next measure what the length of the threads are that are used to make up your threaded muzzle (this measurement will be subtracted); measure the thickness of the flash hiders washer; and the OAL of the flash hider your using.

Start with the OAL of the barrel without a flash hider (+) the thickness of your washer (+) the OAL of your flash hider; add it all up and then subtract this measurement you end up with from measurement for the length of the threads that make-up your threaded muzzle. This will be the OAL length of your barrel with a permanently affixed muzzle device.

You can place the dowel down your barrel after installing the muzzle device; from muzzle to a bolt that's in battery; and the two measurements should equal out each other.