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shenny 03-13-2011 11:36 PM

Trigger question
So I just got a Colt 6940, and I'm very pleased with it so far. Got 200 rounds through it without a single problem! The first thing I want to do is upgrade the trigger. I was thinking about an RRA two stage National Match. I was checking RRA's site at

Rock River Arms: NM Two Stage Trigger

And I noticed that there is a "sporter" version to fit "large pin lowers". My rifle is marked "Sporter M4 Carbine". What exactly does this mean? Do I have to get the sporter version of the RRA trigger and in general what do I need to know about any other parts and their fits?

Dillinger 03-13-2011 11:43 PM

Do you have a set of dial calipers?

Because the "standard" size of "small pin" AR's is about .154" and the "Large Pin" Colts were about .171" or so. Not a big difference, but definitely big enough to cause a problem.


shenny 03-13-2011 11:44 PM

I don't have calipers...I just read somewhere though that they will fit anything except Colt because they have bigger pins... ARG. Not a big deal, but its $50 more!

shenny 03-13-2011 11:52 PM

Solved: I think. Did a little more research and it seems that recent colts all have standard mil-spec sized pins! Yay!

Sniper03 03-13-2011 11:53 PM


As Dillinger said it is a good idea to check with calipers. Please check to be sure but "Your 6940 Colt" should have been manufactured since 2009 and should be the small Hammer and Trigger Pins .154 diameter. (Some call them .155) they are the same small trigger and hammer pin. Meaning the standard 2 Stage Rock River Trigger and Hammer unit should fit in with no problem at all. Just be sure to get the springs installed correctly. A lot of the Post Ban and later Colt AR-15s had the Larger .170 trigger and hammer pins. Please check but yours should have the small pins .154.


shenny 03-14-2011 12:00 AM

Thanks! I really appreciate the input!

WoodysKJ 03-14-2011 12:44 AM

Have you considered these?

Geissele Automatics - Quality Triggers for the Warfighter and Competitor - Super Semi-Automatic

Supposed to be the best. For large or small pins. Gonna put one in my next AR. Tried one in a friends and OH MY GOD what a sweet feeling.

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