I hate that Colt has material separating the pockets of their lower. If I ever want to drop in aftermarket triggers, some of them just won't fit.  Anywhere reputable I can send it to just hog that puppy out to a proper m16 spec? And no, I'm not a glowie or trying to make anything illegal: I just have a decent clone Colt and if I'm gonna have work done, I might as well go all out and make it "proper."

Adco is the answer you seek.  They did one for me years ago, and have been my go to for gunsmithing ever since.

ADCO says no, sadly.  Ah well.

Dremel??

Has this BATF finding changed or are people losing their balls because of the vaccine, other? Which version of the block do you have?

DEPARTMENT OF THE TREASURY
BUREAU OF ALCOHOL, TOBACCO AND FIREARMS
WASHINGTON, DC 20226

NOV 5 1997 F:SD:FTB:RLB
3311


Dear :

This is in response to your letter of October 23, 1997, to the
Bureau of Alcohol, Tobacco and Firearms. In your letter, you ask if
removing the steel receiver block from the lower receiver unit of
a Colt, Sporter rifle would be a violation of Federal law.

The steel receiver block to which you refer, is intended to serve
as an anti-tampering device and prevents the installation of
various AR-15 drop-in auto sears, lightning links, and M16
machinegun fire control components. The steel receiver block is
installed in the sporter lower receiver unit by Colt Firearms and
is an attempt, on Colt's part, to prevent the illegal conversion of
their semiautomatic sporter lower receivers units into machineguns
style receivers. The presence of the steel receiver block is not
required by Federal law.

Based on our research, it is our opinion that the removal of the
steel receiver block, in and of itself, from the lower receiver
unit of a Colt, Sporter rifle would not result in a violation of
Federal law. In addition, the possession, sale, or transfer of a
Colt, Sporter lower receiver unit with the steel receiver block
removed would not constitute a violation at Federal law.

We trust that the foregoing has been responsive to your inquiry. If
we may be of any further assistance, please contact us.

Sincerely yours,


Edward M. Owen , Jr.
Chief, Firearms Technology Branch

Mine is aluminum, part of the forging. It's not the old style pinned block.  No reason why it would be illegal to alter; most other companies don't use lowers with extra crap in the way.

I'd call M60Joe, he's a wizard.

You just have to get someone to finish milling out the lower to get rid of the high shelf, web, and thick walls.

I believe he sold his business 3 years ago or so

No, nothing has changed.

Surprised that anyone would even bother to write Tech Branch with this.

Basically anybody with a mill. Or a dremel, if you don't mind a more crude look.

Can someone post pics of this web in a lower? I have an application that warrants something close to the third hole (For completely non-third-hole purposes), and I'd like to use the web to keep it legal. I've seen the pinned-in sections on older Colts, but I'd like to leave it on an 80%.

See if John Thomas at Retro Arms Works will do it.

Adco outsources all their gunsmithing and one of the key gunsmiths they use passed away unexpectedly very recently, which has handicapped both type and volume of work they can take on.

Anybody with a Bridgeport mill can do a factory looking job.   Any Bubba with a 80% jig can open it up.

What he said.

I’ve got a Colt I had for years with blocked steel insert they use to put in the lower.

My gunsmith (Saltzman Gunworks Tipton, IN) removed it for me for similar reasons.

He’s a full custom shop... never saw something he couldn’t do and do well.

Are there really triggers that extend that far back?  Kinda surprised.

Anyway, as others have said, it would be a straightforward job for any decent machinist, so long as you can tell him precisely what you want.  Remove the FCG and the grip;  then he should be able to hold the lower by the lug where the grip mounts.

Rotary tool. If you want it real perdy, you can but one of those flexible attachments or stands that holds the tool. I have the Dremel models and they works great.

Rotary Tool Workstation