I decided that the sear block in my newly acquired Sporter Colt needed to go.  I've removed the top portion of the block, so I can now use whatever type carrier I wish.  This was not the most cosmetic job, so now it might be time to remove the rest of the unit.  Suggestions ?   Thanks !  

http://www.ar15.com/archive/topic.html?b=3&f=4&t=482041

Took me a minute to understand why the effort and how much it would be. They certainly did do some workarounds in the day.

This was how it was professionally done at SAW (Specialized Armament Warehouse - AZ), the top was milled close to the top of the top of the lower receiver and the front face of the block machined to have clearance with large type hammers.

SAW currently no longer does this service (cost $95) but you could try it if you're handy or have a competent gunsmith do it.

I personally prefer this method because the pins on the side of the lower receiver stays there, if the whole sear block is removed the pins are epoxy bonded in the hole/ holes to cover the hole, if and when the adhesive breaks down the plug will fall out leaving the hole open again.

In the past I used to have 6 pre ban Colt AR but I only had one with the sear block which was my model R6530 Sporter Lightweight carbine that I bought new in 1991, if I still have my carbine I would have just done it this way.

What he said.  Might be worth a call to ken to see if he'd do it again.

Is there a reason why you couldn't securely clamp the lower to a drill press vice and then use an end mill or roto-broach to remove the material with just a few simple plunge cuts?

 
On the new lowers, that is possible, However, even with the sear block, it won't effect any BCG you wish to use.



ETA: I guess you're talking about milling off the top of the old style block. You could do it if you know what you're doing.

 

I believe ADCO offers the service to mill off the top.

Compass Lake Engineering offers this service.

SEND IT OUT TO BE DONE !!!

Sorry about the bold caps.... but I did mine at home, and it was a huge pain in the butt.

The steel that Colt used in the first version is really tough. What I though was going to be a simple project... turned into a complete PITA.

In hindsight, if I had to do it again and knowing what I know now..... I would not hesitate to send it to ADCO, or such.

I finally worked up enough courage to finish the job.  Actually did it with the Dremel in about a half hour.  The single pin on the left side is still firmly in place...tried to knock it out, but the thing wouldn't budge.  Left in place.  The block actually came out  clean with only one tiny scratch inside which was easily touched up with Aluma-hyde.

Pictures please!!