Hi all, first time building an AR. In Ma, so went with preban lower. It’s a colt with Large Pin with a seer block.

I need clarification on what triggers work WITH the sear block in tact. Got a CMC drop in, it does not.

I’ve done a lot of research but I can’t find definitively what trigger works. I do not really want to have to modify the lower.

Thanks in advance to all.

Velocity, Geiselle, Timney?

The only one I know of one, and they may be out-of-business, that is Jewel.

The sear block can be removed, leaving you with any large pin trigger as an option. It will look like ass, with the gaping hole in your receiver. You could epoxy the remains of the sear block in place after grinding off any offensive material that interferes with the new trigger's installation process.

The sear block is HARD and using a hand grinder (carefully) is probably the only way to do it at home. Don't allow excessive heat to build up in your lower. A Dremel tool cut-off wheel and a lot of patience may do the trick. Again, heat is the enemy of your receiver.

Here you go OP

Thank you for that, puts me at ease.

I was worried I was going to have to remove the block.

Depends on the type of sear block. OP needs to figure that out first.

The other kind of block they used looks like THIS -



Compared to what the one you have looks like -



Right behind where Colt is printed is where you want to be looking to quickly spot the difference between them.


The one on the top does not require the trigger itself to be hacked to get things to work...



JP used to make a version for both depending on the block type. (or you could ship them your sear block lower and the 'incorrect' JP large pin trigger and they would machine the trigger to fit with the block properly (mill that one side off of the ass of the trigger)


I believe the JP part number for their adjustable trigger that would have fit with the block you have would have been the JPFCP-2. Discontinued by JP but actually saw one (supposedly new / old stock and still in the package) this morning on gunbroker (for not an insane amount considering what all was included in my opinion).

https://www.gunbroker.com/item/1025206088

The 'EZ' at the end of the part number above means that version has the adjustable safety (no need to file on a trigger pad to adjust that fit)


My Colt with the sear block is the type in the very top picture above. I run the large pin (and less hacked) JP adjustable in it and love it. An awesome completely adjustable trigger with NO worries about having to remove or hack on the actual sear block or the lower to get things to fit or function properly.

Literally everything about the trigger can be adjusted to ones liking... :) Engagement, overtravel, disconnector timing...  



Pretty much run JP triggers in everything now AND keep spares on hand for lowers I may get in the future. Like the way their products have evolved over the years as well...

Older JP on bottom and newer version on top -



Notice how they relieved the safety pad on the one side in the newer version so that 'if' a guy did need to do an 'adjustment' there he would not have to do it on as much material? :)