New frontier lower/trigger swap?

Thread starter #1

bfriendly

Senior Member
I’d like to blame it on a lazy owner having a dirty lower, but on two separate occasions the hammer on my AR15 would fire when the trigger was released. First time it happened was on a deer hunt and the trigger was very hard to pull. When I got up enough strength to fire it, it shot twice! After a few more double shots back at camp, I cleaned the lower best I could and it was fine. A few weeks ago at the range, it did it again. I just cleaned it really good this time and it is fine……..for now
Anywho, The thought of a better trigger has always been appealing and I put this thing together on the PSA/Bobs cheap. My lower is a new frontier all polymer which is very light and I really like it. I’ve never replaced a trigger, but was wondering a few things. Could it solve the issue or would the hammer assembly be the culprit….is it two separate assemblies? Can I drop in a PSA or similar trigger? Love y’all’s thoughts on this as it may be my favorite gun I’ve never killed anything with.
 

transfixer

Senior Member
I have no experience with one of the polymer lowers, and will admit I have some reservations about how rigid they might be ,in regards to keeping everything in perfect alignment? If you aren't real familiar with assembling lowers and swapping triggers I'd suggest you get someone who is to look it over . Maybe they can spot an issue ?

To answer your question though, yes , you can install any trigger made for an AR, any mil-spec trigger, or even one of the aftermarket self contained drop ins , I've swapped triggers around a good bit with the various AR's I have, I generally prefer two stage triggers, with total pull being around 4 or 4.5lbs,

I'd be leary of some of the really low priced triggers from some of the "discount" online retailers, while I have bought some things from them, super cheap triggers or trigger groups from discount sellers with obviously re-branded names I stay away from, as most of those are made overseas
 
CMC drop in triggers are solid and can be had for a fair price from PSA sales. The LaRue MBT for $100 is the best deal out there near as I can tell. Or you can get a mil spec setup from a reputable vendor like Aero for $40.

https://www.aeroprecisionusa.com/fire-control-group-fcg-kit

https://www.larue.com/products/larue-tactical-mbt-2s-trigger/

I’d definitely take the fire control group apart for a solid cleaning. Probably worth picking apart the BCG while you’re at it.

Good luck - gun problems ain’t fun.
 

transfixer

Senior Member
CMC drop in triggers are solid and can be had for a fair price from PSA sales. The LaRue MBT for $100 is the best deal out there near as I can tell. Or you can get a mil spec setup from a reputable vendor like Aero for $40.

https://www.aeroprecisionusa.com/fire-control-group-fcg-kit

https://www.larue.com/products/larue-tactical-mbt-2s-trigger/

I’d definitely take the fire control group apart for a solid cleaning. Probably worth picking apart the BCG while you’re at it.

Good luck - gun problems ain’t fun.
x2 on the LaRue MBT , I have one of those, and it feels so close to a Geissele 2 stage its hard to tell the difference, at almost half the price !
 
Thread starter #5

bfriendly

Senior Member
Thanks y’all I may check them out if I put one in. With the hammer firing on the trigger release, do you think the catch on the trigger may help the issue? What about the ha,mer assembly itself? I’ve never heard anyone switch out hammers, just triggers. I am sure I could handle a drop in trigger job, but i don’t know enough to be able to find the cause of that problem…..if that makes sense.
 

transfixer

Senior Member
Many of the trigger kits come with the hammer, as it is cut and matched to the sear of the trigger, LaRue does, Giessele does, PSA does , and others , and they usually include trigger and hammer springs also,,,, most of the one piece drop in's don't seem to come with hammers I don't think though ? although I haven't bought one of those myself, I imagine they are supposed to be used with a mil-spec trigger .
 
Yep, it’s all one in the same - called a fire control group (trigger, hammer, springs). The drop ins have a hammer too. @bfriendly I have some spare milspec FCGs if you’re ever up around Blairsville. Happy to help out if you’re nearby.

It’s easy to do some function tests with just the lower. Check out this midway video but when you do it with just the lower you have to catch the hammer... without the BCG it’ll slam into the wrong place and cause trouble. The hammer is meant to hit the firing pin. I let it drop on my thumb while testing the FCG like they do here.

 

transfixer

Senior Member
I hadn't really stopped to think about the drop ins also having a hammer, but now that I do, I realize its integral with the housing, duh ! I've just never wanted to buy one of those, as I prefer 2-stage triggers when it comes to aftermarket. I'm pretty much an accuracy snob, and get better accuracy when using a 2-stage, and I like the fact you have to make a deliberate decision to pull the trigger, by taking up the first stage, as you know the next little bit of squeeze is the final drop , kinda hard to squeeze the trigger before you intend to with those !
 
I hadn't really stopped to think about the drop ins also having a hammer, but now that I do, I realize its integral with the housing, duh ! I've just never wanted to buy one of those, as I prefer 2-stage triggers when it comes to aftermarket. I'm pretty much an accuracy snob, and get better accuracy when using a 2-stage, and I like the fact you have to make a deliberate decision to pull the trigger, by taking up the first stage, as you know the next little bit of squeeze is the final drop , kinda hard to squeeze the trigger before you intend to with those !
I’m with you, two stage is the ticket. Never realized how much a difference it made until I had one.
 
Thread starter #10

bfriendly

Senior Member
Thanks again. When I was playing with the lower, I would push back the hammer to charge it, then pull the trigger. While holding the trigger, I’d charge the hammer again. Before I cleaned it real good, the hammer was dropping again as the trigger was released, hence, the double fire.
I’m kinda freaked out now, cause I was just letting the hammer drop without any resistance! I don’t think I broke anything and it was working perfectly when I put it back together, but next time I’ll block or stop it with my finger……is that what your talking about? Man I hope nothing inside crackedfacepalm:
 
Thanks again. When I was playing with the lower, I would push back the hammer to charge it, then pull the trigger. While holding the trigger, I’d charge the hammer again. Before I cleaned it real good, the hammer was dropping again as the trigger was released, hence, the double fire.
I’m kinda freaked out now, cause I was just letting the hammer drop without any resistance! I don’t think I broke anything and it was working perfectly when I put it back together, but next time I’ll block or stop it with my finger……is that what your talking about? Man I hope nothing inside crackedfacepalm:
Yea, you don't want the hammer dropping on the receiver itself... I doubt you busted anything in the receiver but I'd be inclined to take apart that fire control group and give it a better look - or just swap it out all together.
 
if it fires on pull then fires again on reset there may be an issue with the disconnector
That was my first thought as well. The vigorous cleaning temporarily solving the issue is kind of weird though.

Either way, the FCG needs To be removed and inspected. It would be ideal too be able to to set it up in one of those FCG jigs to observe the whole firing sequence outside of the lower.
 
With the hammer firing on the trigger release, do you think the catch on the trigger may help the issue? What about the ha,mer assembly itself? I’ve never heard anyone switch out hammers, just triggers. I am sure I could handle a drop in trigger job, but i don’t know enough to be able to find the cause of that problem…..if that makes sense.
Before you "pull the trigger" on buying new parts--

The NF lowers I've seen have a proprietary polymer hammer (Accutrigger?)
that (to casual perusal) looked a bit different from run o' the mill AR hammers.
The rest of the fire control bits are polymer, also, so you may need to
replace the entire set--hammer, sear, disconnector, trigger.

Hopefully the pin locations/geometry is compatible to standard...

Check with New Frontier, before you buy. Heck, they may offer you a new set
of parts.

Edit: check this out...possibly previous owner put one in, and didn't
adjust properly?

New Frontier Trigger Adjustment Screw
 
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