Aloha!

New to the forum and was wondering if you could help me understand the following issue. I am looking at doing a retro M16A1 build and have an A1-style receiver, flat delta ring, and lightweight contour barrel on backorder through DPMS. Having done some more research on the various lightweight type barrels, it looks like the barrel that DPMS sells (part #BL-L20X9) might be too thick behind the FSB to allow the A1 handguards to fit without modification. I don't mind modding the handguards if it just requires some dremeling of the inside, but figured I would ask DPMS for some clarification. This is the how my line of questioning went:

Me:
Hi, I have one of your 20" lightweight barrels on backorder (#BL-L20X9), and was wondering if a set of the triangular A1 handguards will fit. Thanks for your time.

Staff:
no sorry they will not fit on the barrel. The barrel is about 1/4" shorter in designee

Me:
I am confused-the barrel specified is a standard 20" rifle length barrel, and should take the standard rifle length A1 or A2 handguards since it has the triangular handguard cap and A1 front sight base. Why would it be 1/4" shorter than the government design? I believe this is the same barrel used on the Panther Lite rifle, which looks like it has A2 handguards on it. If this is not the case and the handguards are not a standard size, what handguards do fit on this barrel?

Staff:
the rifle barrel will take the standard length hand guards but not the government designed A1 style as those are completely different in designee. Our hand guards parts number BL-01M will work just fine

Me:
XXX, thank you for the clarification. One last question for you-does the barrel follow the government A1 profile from the chamber to the FSB, or just from the FSB forward?

Staff:
Neither as the original government barrel is completely different then all civilian barrels. They are proprietary to Colt and could not be copied to the T . They are the .750 all the way from the chamber to the muzzle but are a bit shorter to prevent the usage of the Colts parts


So my question to my fellow retro builders is this: Does the DPMS lightweight barrel not take the A1 handguards due to a too-wide diameter at the handguard cap, or due to something else? The fact that he says the barrel is .750 from the chamber to the muzzle seems to me that the barrel would follow an HBAR profile more than a lightweight. I am just shooting for a budget retro build, so originality isn't as important as to me as appearance. Just trying to make sense of it all so I can decide if I need to look at other options or just stick with my DPMS backorder.

the triangular handguards will fit with a little dremelling.  dpms probably doesn't have any on hand since they haven't been in use for nearly 30 years now.

That sounds like a lot of herp 'n derp

If the barrels have an A2 FSB like they seem to do, They should be labeled as such, not A1...

DPMS,

Sent you an email, but looks like you took care of the issue. Thanks for the clarification on the barrel, much appreciated!