Trigger problems after JP reduced power spring change

Grizzlypeg

Grizzlypeg

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I thought I'd try an inexpensive way to reduce the trigger pull weight on my Ar-15. Its built on an SP-1 lower. So I bought a JP products reduced power spring kit. It comes with 3 springs, trigger, hammer and disconnect. Cleaned and lightly lubed the sear surface with some grease.


At the range I am getting either a second discharge of the rifle when I let off the trigger or the bolt closes only part way after the first shot, slinging a cartridge into the chamber (and the cartridge is not binding in any way). I suspect something in the trigger design is preventing a follow through firing and hanging up the bolt on the trigger group.

So, what's going wrong here? I've only heard complaints of light hammer strikes on milsurp ammo with this spring kit. Nothing about actual trigger group malfunctions.

Should I remove all the springs, or can anyone tell me which spring might be causing this malfunction. It sure was nice to have a 4-5 lb trigger pull for only $10 in parts.

The gun shoots perfectly when loaded single shot.
 
I'm no expert, but it sounds like your disconnect isn't engaging properly.

What I do know is that you've essentially made yourself a prohibited firearm and really must put it back as it was until you find someone who knows what they're doing to troubleshoot your problem.
 
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I gotta agree, sounds like the bolt is somehow sticking on the hammer (only part that touches the bolt) Does it do that when you dry-cycle it?
 
syndochrist said:
I gotta agree, sounds like the bolt is somehow sticking on the hammer (only part that touches the bolt) Does it do that when you dry-cycle it?
Click to expand...

No. Functions fine on dry fire and single shot loaded in the mag (as mag follower holds bolt open). It didn't do it every time, but it did it 2x firing when I let my finger off the trigger (or was it still held down?) and then it started hanging up the bolt on the hammer. So after that, to continue testing my loads, I fired it one shot per mag at a time.
 
As I understand your first post, you only replaced three springs. Correct?

Did you install these springs correctly?

Since this trouble, did you look inside to see if everything is still installed as it should be?

Specifically that the disconnector spring is where it's supposed to be and that it was installed oriented correctly as it may have moved if it wasn't.
 
All the springs are still in position. I didn't previously observe how smoothly the disconnector moves within the trigger, when the hammer is forward, but, I can say the the disconnector doesnt move very smoothly in compressing the small coil spring. It has a real dragging, binding kind of feel to it. The coil spring that came with the JP kit looks a little different from the original spring. I'll take it apart and compare the two disconnector springs. I wonder if its binding and not providing proper force against the disconnector? It looks like its a tight fit down in the trigger's spring pocket and might be binding. I'll compare the two and report back.
 
Dummy reporting back. The new, JP spring was tapered. It was installed upside down, resulting in binding and lack of tension on the disconnect. It now moves smoothly and hold tension throughout the position of the disconnect. Back to the range!!
 
Glad that worked out for you. :)

It's always a stupid little thing, isn't it? Many and myself have been down that road before.

Happy shooting.
 
Bad news. It still is doing it. After I fire a shot, I find the bolt half way forward. The only thing that could be stopping it, that I can think of, is the hammer. So if the hammer is following the bolt, the disconnect must not be working properly. Time to switch back to the original disconnect spring. Is there any way a lighter hammer spring or trigger spring could cause this? I can't see how.

Edit: Swapped in the original disconnect spring. Its significantly heavier than the JP spring that came in the kit. Why would one want to soften the disconect spring? What role does it play after the trigger returns forward and the hammer rests on the sear?
 
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Edit: Swapped in the original disconnect spring. Its significantly heavier than the JP spring that came in the kit. Why would one want to soften the disconect spring? What role does it play after the trigger returns forward and the hammer rests on the sear?[/QUOTE]


I don't know why the disconect spring would be softer, in the army we upgraded the springs to a stronger one to prevent double taps. Good luck with the old spring.
 
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