New AR problem- trigger not resetting.

[U8395279]

Gentlemen, although it's a BRO trigger, it was not purchased from BRO. It's one of the triggers from JSE Surplus with the BRO logo milled off. It is not under any warranty, and I haven't even established that it's the trigger that's the problem.

The manufacturer's logo has been removed, and no warranty of any kind given?

That sounds rather odd to me. I would hesitate buying a product under those circumstances.
.

 

[Velzey]

I've wondered if anyone ever buys those speakers that those guys sell that say they are just like the big mfg !

 

[Garg]

My IMI ammo in Ironbar's rifle...
My upper swap with Ironbar's lower?
My lower swap with Ironbar's upper?
Will the trigger reset issue isolate, vanish?
Buffer Spring?

I think you have two potential problems here.
1. Is the lower Ironbar built a carbine, or rifle lower length, ie. tube, spring, and buffer.
It is a rifle upper, no/yes?
2. The problem "SHOULD" follow the lower, if it is a trigger group issue.
If the problem follows the upper, see No. 1
YMMV,IMHO,IHNIWITA.
Is the bolt carrier 15, or 16? semi, or full auto?

Edit: I have seen 20" uppers run all day on carbine length lowers....it could be short stroking though...

 

[rick benjamin]

Tomorrow may provide the answer.
We will have lotsa parts to test with

 

[Garg]

Standard CAR….. 2.9 oz.
H buffer is ….. 3.8 oz.
H2 buffer is….. 4.6 oz.
Rifle buffer is….. 5.17 oz.
9mm buffer is….. 5.5 oz.
H3 buffer is….. 5.6 oz.

 

[Velzey]

I think you have two potential problems here.
1. Is the lower Ironbar built a carbine, or rifle lower length, ie. tube, spring, and buffer.
It is a rifle upper, no/yes?
2. The problem "SHOULD" follow the lower, if it is a trigger group issue.
If the problem follows the upper, see No. 1
YMMV,IMHO,IHNIWITA.
Is the bolt carrier 15, or 16? semi, or full auto?

Edit: I have seen 20" uppers run all day on carbine length lowers....it could be short stroking though...

This is what was built...
It no go

 

[Garg]

An H2 might be the fix.

 

[Caveman Jim]

I have too, but Bronze can be underpowered when using Spinco Blue or Red spring with an H2/H3 buffer setup to run heavier 175gr loads.

Gotcha, mine is stock as a clock....

 

[oli700]

I make my own, my H3's come out to 5.4

 

[Ironbar]

OK gents, I wasn't able to get to the range today with Rick because I had to stay home with the kiddo. However, after opening up the rifle and probing around, here's a couple things I found:

1) I found that my trigger had the same problem as this fellow in the video:

Here is a guy that is having what sounds like a similar problem with a BRO rifle (I assume has the same trigger)

I took a dental pick just like this guy did, and the disconnector hook did indeed have a distinct burr on the edge. I took 600 grit sandpaper and filed it smooth. I still don't know if it was this burr that was responsible for disallowing the trigger reset, but I noticed since sanding it that the reset is very crisp now whereas before I had some grit when releasing the trigger.

Is there anything stamped on the end of the buffer or is in blank?
The weight are as follows:
carbine buffers (blank, no stamp) 3.0 oz,
(H) 3.8 oz
(H2) 4.6 oz
(H3) 5.4 oz
(HSS) 6.5 oz

2) I pulled the buffer from the tube, and there was nothing stamped on it other than the Palmetto State Armory logo. I weighed it, and it's right at 3oz. Should I replace this with a heavier weight buffer for my 20" rifle?

 

[rick benjamin]

Good discovery and fix!
Perform one troubleshooting fix at a time.
Any more and we won't know what you did to fix this.
Let's shoot it and see if the problem went away

 

[Garg]

Sounds like you might be on to something there Ironbar.
When ever I build a new lower, I like to cycle the action several dozen times, as sometimes they are a bit stiff. The stiffness sometimes will exacerbate these kinds of problems.
Good luck. Hope to hear good news soon

 

[XSubSailor]

I'm betting that cleaning up the disconnector mating surfaces should cure the problem. I doubt that a light buffer would cause the issue you're experiencing, since a lighter buffer/spring combination may punish the rifle/or shooter with excessive recoil and/or slamming the bolt to the rear harder...a too heavy buffer/spring combo "could" cause what you're describing, but since the rifle ejects and chambers another round properly, clearly the BCG travel is sufficient to operate a properly functioning disconnector assy.

That being said, once the trigger group is running properly, you may want to try a heavier buffer to minimize the mechanical shock to the upper receiver. If the buffer/spring is mismatched to the gas length and/or bullet weight, the BCG may be slamming rearward against the receiver before the spring is able to cushion and stop it.

 

[oli700]

like I posted above I've worked through your problem.....

It wont be 100% till you replace the disconnector.........you can get it close but since it has a burr the metal is already soft or through the surface hardening . There for a new burr will develop shortly

 

[Velzey]

Fix the burr and take it out and shoot it! Diamond file or a small diamond hone and then stone it smooth.

All those parts are case hardened .030 deep so you need to take allot off to get to the soft stuff.

 

[Ironbar]

like I posted above I've worked through your problem.....

It wont be 100% till you replace the disconnector.........you can get it close but since it has a burr the metal is already soft or through the surface hardening . There for a new burr will develop shortly

I suspect now that the reason these triggers had the logo's milled off and sold for ½ the cost is that they might have been manufacturing rejects.

 

[oli700]

I suspect now that the reason these triggers had the logo's milled off and sold for ½ the cost is that they might have been manufacturing rejects.

you could be right or that disconnector missed the hardening process, likely why it developed the burr in the first place if you really think about it ....
at least you know now, super frustrating problem

 

[Velzey]

Does a file grab the material or does it skate right off?

 

[oli700]

make sure you don't have a dull file for that test

if it came burred you might be in luck

if you shot the burr in you probably not

 

[Ironbar]

OK! It appears that I got it worked out! Thanks once again to Rick Benjamin for the invite out to DRRC to get this sorted once and for all.

Turns out it WAS the burr on the disconnector hook that was disallowing the trigger reset. As I reported earlier, I sanded down the burr on the hook with very fine grit paper until I could feel no snag with my dental pick. I then greased the surfaces generously with Mobil 1.

This afternoon it functioned flawlessly. No problem with reset at all. Every shot same as before. Over the course of sight-in, I managed to get my groups down to 2" at 100 yards. I think now I'd like to put a free float hand guard on to see if I can squeeze out a little more accuracy.

Thanks a million to bolus for posting up that video of the guy with the same BRO trigger problem. Man, what a life saver!!