Greetings,

I have a Colt sear block, large pin lower. I specifically wanted a 2 stage trigger and did not want to remove the block. The one I found was made by JARD (only the non-adjustable version will fit). That seemed about the only option in my searching. If you want a single stage there are more options available. Though not nearly as nice a the Geiselle 2 stage triggers I have in my other ARs, the JARD is pretty decent.

Good luck!
Regards, Jim