AR assembly question

[Tony Wells]

I'm working on a friends AR-15 and can't remember what holds the buffer retainer and spring in place. Someone else ha been working on this one, and it is set up to swap uppers to shoot cheaper .22 LR for fun for the kids at a day camp, and the normal .223 for regular use. The .22 naturally has a lighter buffer and the action spring is different, so I suspect that the prior "helper" did not reassemble something properly. Does the receiver extension simply thread in and capture the buffer retainer on the shoulder the retainer has? I can't see any other way, but it's been so long since I've scattered one I can't remember.

 

[Rbeckett]

The buffer is supposed to be caught by a spring loaded pin in the bottom of the tube. I have seen a bunch broken off and also never reinstalled. Makes the next disassembly a real PITA too. Hope that is what youre talking about by your description. I have a Ruger 10/22 with a 50 round magazine. Nothin better for plinking at targets and having fun with water bottles and old glass bottles on a board at 100Yards. You can burn through a brick of ammo in no time at all, but it is a blast doing it too.


Bob

 

[Tony Wells]

Correct, Bob. That little pin with a step in it, and is hollow is called the buffer retainer (duh), but there isn't anything to hold it in, unless the receiver extension does thread in deep enough to capture it. It can easily be screwed in that far, so I believe that's the retention mechanism. And last time someone broke it open, the pin and spring went, and only the pin was recovered, so I have to come up with a new spring. I have some that I believe will work, but not sure yet.

The kids really enjoy shooting this thing, and using the .22 LR upper, it isn't too expensive. This is for the same day camp I was working on the Jackal 9mm blank gun that shoots full auto the other day for. They do shotguns, rifles and pistols there for boys and girls. And they shoot live ammo after a bit of training with blanks. The camp goes through almost 30k rounds of .22 LR. They're looking for a bunch of .223 though. Kind of rare and pricey this year.

 

[GoMopar440]

The buffer tube screws into the lower receiver until it covers the fat part of the buffer retaining pin, but not far enough to keep the pin from moving up and down freely. The skinny part of the pin sticks up and holds the buffer and buffer spring inside the tube. The threaded lock ring on the outside screws down on the buffer and locks against the receiver body to lock the buffer tube in place.

To remove the buffer and spring just push the buffer retaining pin down out of the way and let the spring push the buffer out of the tube. Just be ready to catch it with your free hand as the spring can be strong enough to launch the buffer across the room if you're not careful.

Springs can be found at places like Brownells or Midway, but you could probably find something you can make work at a local hardware store if time is a concern. It's not a very stiff spring so it should be easy to duplicate if needed.

 

[Tony Wells]

Thanks, 440. That's the only way I could see that it could be. Somehow, since this one gets swapped out quite a bit, I'm thinking that the guy who has been "helping" didn't really know what he was doing and backed out on the receiver extension. At least that's what I think you mean by buffer tube.

I did find a decent parts breakdown here:

https://www.ar-15.co/threads/19947-AR-15-Parts-Breakdown-Reference

I don't think the spring is all that critical either.

 

[cdhknives]

Screw in the buffer tube until just before it touches the tip of the retainer pin. It will cover the edge, holding in the pin while allowing the point to extend high enough to stop the buffer.

 

[Tony Wells]

Thanks, I appreciate the picture. Now all I have to do is figure out how to fix a mfg problem between the two uppers. The break open pivot pin is a little different between the two, and there's not quite enough meat to ream out the small one without weakening it. I don't understand why they couldn't make the .22LR the same, so everything would fit up correctly. I may have to TIG up the lug a bit and ream it anyway.

 

[CharlyArmy]

I'm not too familiar with dedicated .22lr uppers for the AR platform as I use the .22 conversion kit from Ceiner.

I don't understand why this helper has been switching out the buffer tube, buffer spring and buffer to convert it to .22lr use. The receiver IS aluminum and the constant switching of the buffer tube will eventually cause excessive wear and render the lower receiver unserviceable.

Before doing any tig welding on the upper, maybe you should consider buying a in spec upper and switching them out.

 

[pineyfolks]

There are adjustable pins that let you use small pin and large pin uppers and lowers together, I never cared for them but they may be ok on a rimfire setup. That may save modifying the lower or upper. If you still have loose fit issues after installing the pin check out an accu-wedge, its a small piece of rubber that takes up the space. I use a ciener type on mine

 

[cdhknives]

I'd work with shims and pins a lot before I did anything to bust the surface treatment of my receivers....just MHO.