UPDATE: AR-15 Buffer and Spring Help Needed

[Radar]

I have to disagree. The silent capture springs don’t do anything a properly tuned buffer a d spring can’t do. In fact, I think they are worse. I’ve seen the lock up more than one gun

How do they cause a ar to lock up?

 

[jelenko]

When the AR realizes how much the buffer costs, the gas port snaps shut just as the bolt carrier is in mid flight - causing the bolt carrier to tilt and jam.

 

[mac86951]

Thanks for all the help. You guys have offered just what I was looking for, as I haven't had to deal with this problem in the past.

I am working on it, and this is my plan.

1. Remove buffer weights to see if I can get it to run with the rifle length buffer and spring. If that doesn't work...
2. Measure and make a spacer to try to fit the shorter (carbine length) spring and buffer into the A2 stock. If that doesn't work...
3. Get a replacement long spring and start cutting it down to shorter lengths and use the A2 buffer and adjust weights and length of spring. If that doesn't work...
4. Get another bottle of whiskey and consider opening the gas hole, although I believe it is at .090 already.

I really don't think I need the JP stuff, as I can usually figure things out on my own if I have a little guidance, and the cost is more than I really want to spend.

It runs with the M4 stock, spring and buffer, so I really think Ggmac has the answer. I just don't want to overlook the possibility that working with the A2 buffer weights might get it running.

Thanks again guys. Very helpful.

Jim

Ok, i gotta ask; does your barrel have a shoulder for the gas port? How is your gas port installed, clamp on or set screw? Do you need to account for the Delta ring spacing to align the port?

I'm sure you've covered all of the above, since you're using an adjustable gas block, going to a 0.093 or 0.096" gas port isn't that big of a deal, many reasons that it makes sense, but I'd check the above just to be certain before drilling.

Any chance you have a bore scope? I'm curious if your gas port is in the lands or grooves.

-Mac

 

[pdhntr]

Ok, i gotta ask; does your barrel have a shoulder for the gas port? How is your gas port installed, clamp on or set screw? Do you need to account for the Delta ring spacing to align the port?\QUOTE

Hi Mac,

Please see post #20. I have the problem figured out. It has a lot to do with not "channelling" my inner knowledge and getting older.

However, I will answer your questions. I cut down and rechambered a Krieger barrel that was not being used from a bench AR. I cut a shoulder .010 in front of the face of the gas block. It is a clamp on gas block. My understanding of terminology is the "port" is the hole. No, I don't need to account for the Delta ring spacing. There is no delta ring. Free float barrel. The front sight on a mil-spec AR aligns the port and the gas tube, not the delta ring.

I'm sure you've covered all of the above, since you're using an adjustable gas block, going to a 0.093 or 0.096" gas port isn't that big of a deal, many reasons that it makes sense, but I'd check the above just to be certain before drilling.

Any chance you have a bore scope? I'm curious if your gas port is in the lands or grooves.

-Mac/QUOTE

The gas port is much larger than it needs to be. About 3 times what I actually need.

I have a couple of bore scopes.



I don't believe Krieger is offering a 20 cal AR-15 barrel any longer. Still shoots well.



Thanks.

Jim

 

[VA_XTC_Shooter]

How do they cause a ar to lock up?

I edited my post. I mis-remembered an issue. I reached out to a friend that was working on a rifle with me. I was wrong, The gun had a JP spring, but the problem was the buffer tube and buffer retaining pin binding the JP spring.