AR-15 Hammer not locking back.

[DadSmith]

I'm having a problem with the hammer not locking back after discharging a round.

[FONT=Tahoma, Arial, sans-serif]What happens: round fires, bolt cycles and loads a new round, but it isn't cocking the hammer. I can manually pull it back far enough to cock it and it cocks then i let the BCG slide forward and it fires kind of like a bolt action. It just started happening today at the range. I have over 2,000 rds through it. I cleaned it just to be sure that was not the problem. I cannot find any reason why it should be doing this. Has anyone had this problem? If so whats going on?

5.56mm[/FONT]

 

[churchmouse]

Do you mean it will fire with the trigger after you pull the charging handle to cock the hammer.
If so check the gas tube on the BCG. If tight dismantle and check the rings in the bolt. Also clean that area really well if you have not been doing that.

 

[Hop]

Worn disconnector or broken disconnector spring maybe. You need to do a no-ammo-anywhere-near-the-gun-function-test.

Keep the trigger back while cycling the bolt. When the trigger is to the rear, the disconnector should grab & hold the hammer. Release the trigger and the hammer should click forward and get caught on the sear.

 

[DadSmith]

That's what I mean.

I did clean it at range.

Hop I'll try that now get back to you.

Okay Hop I did that test. I let go of trigger nothing happens. If I push the trigger forward it will engage the hammer. I'll have to take it apart see if the spring is broken.

 

[Chr15topher]

Have you recently taken your trigger group apart? The reason I ask is because I was having the same problem a couple of months ago and it turns out I put the trigger spring in backwards.

 

[DadSmith]

Worn disconnector or broken disconnector spring maybe. You need to do a no-ammo-anywhere-near-the-gun-function-test.

Keep the trigger back while cycling the bolt. When the trigger is to the rear, the disconnector should grab & hold the hammer. Release the trigger and the hammer should click forward and get caught on the sear.

Hop the disconnector spring had came out a little and was binding up. I took it out looks okay. I put it back in it seemed to be caught on a burr I think I pushed on it with my punch about 10X and it seated like it should. It's working again.

What's your suggestion replace or see how it works?

 

[DadSmith]

Have you recently taken your trigger group apart? The reason I ask is because I was having the same problem a couple of months ago and it turns out I put the trigger spring in backwards.

No its been in since I built it.

 

[Trapper Jim]

No its been in since I built it.

Please take it to a professional certified gunsmith. Just sayin.

 

[DadSmith]

Got it working already. Don't need a gunsmith for a spring.

 

[bwframe]

What was the issue? Trigger spring initially positioned incorrectly?

 

[Hop]

If the disconnector doesn't catch the hammer, the hammer will follow the bolt and not stay cocked. Hammer follow can lead to full auto runaway in some gun/ammo combinations so be careful testing it.

One end of the disconnector spring is a bit larger diameter. That end goes down.

I'd open the gun and do the trigger group function test until you are satisfied it's all working correctly.
Youtube =
[video=youtube_share;bH6kQv65SuY]http://youtu.be/bH6kQv65SuY[/video]
[video=youtube;vHamYP6Vdtg]http://www.youtube.com/watch?v=vHamYP6Vdtg[/video]

 

[DadSmith]

What was the issue? Trigger spring initially positioned incorrectly?

The disconnector spring had came out a little and was binding up. I took it out it looked okay. I put it back in it seemed to be caught on a burr I think. I pushed on it with my punch about 10X and it seated like it should. It's working again.

I think it's just a freak thing that happened. I've never experienced it before with my other AR's. I cleaned it at the range. When I looked in all was correct from what I could see. I did the test Hop told me to do. It failed. So I took the hammer out and the disconnector out and seen the disconnector spring was up and out a little and was binding up. I took it out looked perfect. Then went to seat it back in and the above happened.

I should have taken a picture, but didn't think about it until now.

Hop I bet that was the problem. I had the large end up and it came out over the trigger and bound it up. Surprised it took over 2000 rds to do that.

 

[Trapper Jim]

Got it working already. Don't need a gunsmith for a spring.

I heard something like this from a shooter from FT Wayne building his own. Good luck to you.

 

[churchmouse]

I believe what people are saying is that using a punch X10 to get a spring that should fall into place is indicative of a deeper problem and not just a random issue. Just because it seems to be OK I would personally not be satisfied with this. The rifle could be dangerous to you and or anyone around you.
Please look deeper into this issue. To let it go could be serious. Not sure of your location but I am sure there is someone willing to put another set of eyes on it.

 

[DadSmith]

Okay will do. It actually didn't take that much to get it in. I just did it about 8X more to make sure it wasn't binding up.

 

[Hookeye]

My guess is the disco spring was in upside down.
The larger coil that "holds" it in, was up.
He flipped it and just to make sure, tapped it down a few times.
Learning curve.

 

[DadSmith]

My guess is the disco spring was in upside down.
The larger coil that "holds" it in, was up.
He flipped it and just to make sure, tapped it down a few times.
Learning curve.

Yep that sums it up very well. I've built several, but never ran into this. So I'm sure I installed it wrong when I put it together. It just took awhile to cause a problem. It's running good again. I stopped at range on way to work, and let fly. It ran like it's suppose to.

Guys thanks for all the helpful replies. I'm very grateful for the speed in which you all helped me fix this problem.

 

[1mil-high]

Good diagnostic above, but as another level of protection you could just buy a trigger assembly spring kit and replace them all to make sure everything is fitting and working properly. Or, use this as a chance to upgrade triggers all together haha

 

[Hop]

Haha, yes... a perfect excuse to get a Larue MBT!

Using Tapatalk to annoy my INGO buddies cameramonkey & churchmouse. Hi!

 

[BiscuitsandGravy]

My guess is the disco spring was in upside down.
The larger coil that "holds" it in, was up.
He flipped it and just to make sure, tapped it down a few times.
Learning curve.

Good times! Been-there-done-that- yadda yadda...

LaRue MBT as others said.. I think they are on sale... Hint Hint. Why yes, yes they are... https://www.larue.com/products/larue-tactical-mbt-2s-trigger/

The best $80 you can spend.