OK, AR gurus...

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

BryanDP

Sharpshooter
Special Hen
Joined
Jan 6, 2007
Messages
2,793
Reaction score
305
Location
Tulsa
I bought a couple of complete (minus buffer tube, buffer and spring) Anderson lowers at a gun show recently. I was going to use them for a couple Ciener .22lr kits that I was finally going to put in a couple of unused complete uppers. I put everything together and the kit would fire fine once but would not reset the trigger. If I charged it again it would fire again. I then put the .22lr upper on another lower and it worked fine. I then put a .223 upper on the Anderson lower and it had the same problem so by process of elimination I figured out the problem with the two Anderson lowers.

When I remove the upper and work everything manually it seems to be working just fine, but clearly something is amiss. The only thing visual that is different is the hammer. On the lower that I know works, it is a black hammer with a rear-facing "claw." On the two Anderson lowers that aren't working, it is silver in color and no "claw." I did some research and one thread said to check the installation of the disconnector spring and the disconnector. I did this and they both appear to be installed correctly, using the "working" lower as a guide.

Any idea what would keep the trigger from resetting on a lower where the upper is known to function fine on another lower?

UPDATE: I did some more test firing. The hammer seems to be going too far back when it is set back by the cycling of the upper. The trigger issue is resolved by charging the bolt again or by turning the safety selector to "safe" and back to "fire" between each round. I'm sure something is just installed incorrectly but my lack of experience has me stumped as to what it might be.
 
Last edited:

bigfug

Sharpshooter
Special Hen
Joined
Oct 24, 2008
Messages
5,152
Reaction score
878
Location
Moore
Can do one of two things, polish the hammer/sear, or take a nail file, something real fine to it. Other option is, put something on tv, and sit there with the lower, and work that hammer repeatedly. Block it from hitting the lower with your hand, reset, do it again, several or more times. My PSA premium did this. A burr small enough I couldnt feel, was causing it to hang and not reset. If I charged it, I'd get the one shot. Every once in a while, while I was working it by hand, it wouldnt reset on me, but like I said, after several dozen "dry fires", I dont have any problems.
 

BryanDP

Sharpshooter
Special Hen
Joined
Jan 6, 2007
Messages
2,793
Reaction score
305
Location
Tulsa
Can do one of two things, polish the hammer/sear, or take a nail file, something real fine to it. Other option is, put something on tv, and sit there with the lower, and work that hammer repeatedly. Block it from hitting the lower with your hand, reset, do it again, several or more times. My PSA premium did this. A burr small enough I couldnt feel, was causing it to hang and not reset. If I charged it, I'd get the one shot. Every once in a while, while I was working it by hand, it wouldnt reset on me, but like I said, after several dozen "dry fires", I dont have any problems.

Thanks for the info. I'm extremely suspect because this is two lowers behaving the exact same way. Also, I did some more test firing and moving the safety selector from "fire" to "safe" also resets the trigger and allows me to fire the next shot.
 

NikatKimber

Sharpshooter
Staff Member
Special Hen Moderator
Joined
Jan 2, 2006
Messages
20,771
Reaction score
1,492
Location
Claremore
Did you actually remove the hammer to check? I did this on my first lower and couldn't tell without removing it. I'd remove and verify correct orientation of the hammer and trigger springs. Only after that would I look at modifying parts.
 

BryanDP

Sharpshooter
Special Hen
Joined
Jan 6, 2007
Messages
2,793
Reaction score
305
Location
Tulsa
Did you actually remove the hammer to check? I did this on my first lower and couldn't tell without removing it. I'd remove and verify correct orientation of the hammer and trigger springs. Only after that would I look at modifying parts.

I bought this one assembled except for the buffer tube assembly. I did take it apart and it was assembled correctly. I even built a stripped lower and LPK just to make sure I wasn't seeing it wrong, but I didn't think so because I had a working example on my bench as well.

I did go ahead and do a little filing. It worked beautifully on one of the two lowers with the issue. On the other it wasn't working and then suddenly it worked too good. I will be buying a new hammer sometime this week.

Thanks all for the consultation!

Bryan
 
Last edited:

Shootin 4 Fun

Sharpshooter
Special Hen
Joined
Feb 23, 2009
Messages
17,853
Reaction score
1,103
Location
Bixby
We've seen several of these. The original buyer assembled the trigger/disconnector incorrectly. The disconnector spring is in upside down. The wider end should be in the trigger.
 

BryanDP

Sharpshooter
Special Hen
Joined
Jan 6, 2007
Messages
2,793
Reaction score
305
Location
Tulsa
We've seen several of these. The original buyer assembled the trigger/disconnector incorrectly. The disconnector spring is in upside down. The wider end should be in the trigger.

I saw some mention of that on some searching that I did, but that actually wasn't the issue in this case. i took it apart and put it back together a few times and it was right for sure. Nothing improved until I hacked around on the hammer. I fixed one of them and fixed the other one too good. :( I think I'm going to just write these two off and replace the hammer if not the entire trigger group.

Bryan
 

Similar threads

  • Locked
[4Sale]
  1. For Sale
Special trigger ar15 lower
  • Sub Category: Rifles
  • Sale Price: 500$
Replies
2
Views
612
[4Sale]
  1. For Sale
13.9 p&w ar 5.56
  • Sale Price: 700$
  • Caliber: 5.56
Replies
1
Views
273
[Sale/Trade]
  1. For Sale
  1. For Trade
Sig P226
  • Sale Price: 750$
  • Caliber: 9mm
Replies
0
Views
156
Replies
3
Views
397

Latest posts

Top Bottom