How to remove a Colt Sear Block

[Quarterbore]

Introduction:

The Colt Sear Block is a extra piece of hardened steel that Colt added to their lower receivers to prevent the addition of a Drop In Auto Sear or Lightning Link to their receivers. In addition, the rather creative location of the pin used to hold this sear block in also prevented the drilling of the receiver for the addition of a traditional M-16 sear as well. Colt added these stupid blocks by their own choice and there is no legal requirement for these so they can be removed if the owner oof one of these Colts wanted to do so.

The sear block sometimes causes problems for people that wish to use some after market triggers and it obviously causes problems for people with registed DIAS and LLs. In addition, M-16 carriers including 9mm Bolt Carriers cut to M-16 profile will hit the top of a sear block. Normal AR-15 carriers including closed and open Colt "C" type carriers will work with the sear block without any need of modification.

The purpose of this thread is to show some methods that can be used to remove these sear blocks. Colt is the only manufacturer to use these sear blocks.