Larue MBT trigger pin fit

[msedward43]

Hey guys, I've been a lurker up until now and have searched the forums as much as I could, but I can't seem to find an answer.

I picked up 6 of the LaRue MBT two stage triggers from LRT over the last few months and I put them in 6 different lowers (2 Aero M4E1s, a Spikes Tactical, Aero Gen 2, 2 PSA) and noticed that there is some "play" with the trigger pins in the holes when pulling the trigger in the first stage (whether on safe or without safe) for 4 of the 6 trigger's lowers. they move back and forth a slight bit in the hole when it's pulled/released and while I know people talk about excessive slop being bad, I didn't know if this amount of play was acceptable or not. Interestingly enough it doesn't happen with a mil-spec trigger in the same lower (I'm wondering if it's due to a single stage trigger putting more tension on the pins vs. the first stage of a 2 stage trigger where it might be "looser" tensioned and more visible), or any other lower with my regular single stage triggers either. Just the MBT triggers. Now they're not flopping around in the hole or anything, and you have to look closely at the trigger pin fairly close to see it shift, but I just wanted to know if this is normal, or whether it's excessive slop and I'd need to go up to a 0.155 or 0.1555 diameter pin to take up the slop as I think Mark supplies 0.154 pins.....(all the information I could find on here and TOS was about EXCESSIVE play, but no information on how much was acceptable and how much was excessive). Below is a video I made just a few inches away from one of the the lowers to show the movement.

I just wanted to know whether this is just me being OCD and overthinking it due to ignorance, or an actual issue, or if other people noticed the same thing on inspection. I know that different lowers can have slightly different tolerances, and if maybe one of the lowers had this I would have said "huh, maybe it's out of specs", but it fits mil-spec triggers just fine without it shifting in the hole that I can SEE and it happened on one of the M4E1s, 2 of the PSA Safe/Fire lowers, and a Spikes Tactical Snowflake lower doing the same thing. As I said, I've never seen this before, and these are my first 2 Stage triggers so I haven't had any experience outside of Alg ACT or BCM PNT or basic mil-spec triggers

https://youtu.be/PkQAM-sgm5s

[Renegade04]

I have several MBT-2S triggers in as many different lowers. I have yet to have an issue with pin fitment in any of the lowers. All of my lowers are within spec. BTW, none of the lowers of which I have MBT-2S triggers installed are Aero Precision, Spikes, or PSA. They do include McKay Enterprises, Quentin Defense, Nodak Spud, C.M.T.S., and Del-Ton for now.

[mike_f]

I have 4 MBT's installed in two PSA, an Aero Precision Gen 1, and an Aero M5 .308 lowers. None of them have the movement shown in your linked YouTube video. I don't really see any pin movement in any of my lowers.

I don't know if the movement shown in your video is significant or not.

[msedward43]

interesting.. it happens with 4 of the lowers (both PSA, the Aero M4E1 and the Spikes) in nearly identical fashion. The other M4E1 shows no movement and the Aero gen 2 FDE doesn't either. The strange thing is that a mil-spec trigger in the same 4 lowers will show ZERO movement whatsoever ...

the 4 aren't wildly flopping around as you can tell, and you do have to look at them from about a 12-24 inches away to notice, but still, kinda weird that 4 lowers from 3 manufacturers from different purchases show the same "issue"

[bamashooter]

Pretty good data on triggers (1st reply to OP) if you haven't already seen it. https://www.ar15.com/forums/ar-15/Ge...ent/66-703589/

[msedward43]

Pretty good data on triggers (1st reply to OP) if you haven't already seen it. https://www.ar15.com/forums/ar-15/Ge...ent/66-703589/

Thanks for replying, in my OCD researching the last few days I stumbled across that article and think I understand MOST Of it. However, I couldn't seem to notice if my particular issue was addressed in that writeup. For example, I'm well aware of the slight left to right shift of axis pins (that happens with most every lower I've seen), and get that there must be a little bit of a gap in there (e.g., you don't want the pin literally locked metal to metal along the pin hole walls to allow slight rotation), but I wasn't seeing anything about the slight "back and forth" movement I was showing, and I was just concerned that the amount shown would be considered excessive wallowing in the hole. Again, if I misunderstood something in that post or missed something due to ignorance please let me know, as this particular thing is something I don't have as much experience with (triggers)

[Stickman]

#texasspec

[26 Inf]

#texasspec

That was helpful. We know you have a hard on for LaRue.

[Stickman]

That was helpful. We know you have a hard on for LaRue.

That was his answer when people wanted to know the deal with his BCGs, so it seemed fitting here as well. No "hard ons" here for any dudes, sorry that he gives no answers when people ask questions and he berates them. If you want to white knight for him, that is on you.

Since you didn't think it was helpful, I'll comment to the OP that he should return the trigger and get a Geissele.

#bettertrigger

[grizzman]

I have MBT-2Ss in Centurion, Colt, Mega, and Aero M5 lowers. They all exhibit different degrees of movement. I bought the first one 10 months ago, and didn't notice the movement until I installed one 4 months ago.

I pulled the components out of a Colt lower and replaced the pins with factory Colt pins. The very slight (only visible at a certain angle under good light) movement exhibited with this lower didn't change. Oversized pins might eliminate the movement, if they're able to pass through the receiver, but the movement is so slight that I'd be very surprised if it has any affect on the HA Aluminum.