AR mechanics?

[Guest TnTnTn]

I was shooting one of my ARs today and had a problem. The bolt didn't close fully after firing the previous round. The round was about half way in the chamber. I could not get the bolt to retract to clear the cartridge manually and had to take a brass punch and tap the bolt carrier to the rear until the loaded cartridge cleared the ejection port. Now of course the bolt wouldn't go forward so I couldn't open the rear pin to unhinge the upper. Next step was to push out the two retaining pins and with a bit of lift and pull the upper came loose from the lower. It was under pressure and I controlled the buffer and spring as I separated the two parts. Now for the issue. The buffer detent and spring had popped out and were laying in the trigger region of the lower. The detent is supposed to be contained by the buffer tube or receiver extention but it 'barely' catches the shoulder of the detent. There is a halfmoon notch at the bottom of the buffer tube by the detent. Here is my question. It looks like I could loosen the castle nut and turn in the buffer tube 1 turn to give more shoulder for the detent to be captured and then retighten. The stock is a DPMS 6 position Pardus that is slanted at the end(mil spec?) I reckon. Is there anything wrong with this plan. What limits the position of the buffer tube in the lower? Is it just supposed to bump up against the detent capturing the shoulder of the detent? Looks to me like it should have been turned in one more thread when originally assembled. I bought it a couple of years ago from RGuns as a complete lower. It has not had more than a few hundred rounds through it. RGuns said to send it back and they would have their 'smith' look at it. If I could just 'fix' it myself I would prefer that. Thanks for any help. TTT

[Smith]

You're buffer tube is a commercial not mil-spec if it is slanted, but that doesn't matter in this case. Turn the tube in there as much as you can without binding the pin and tighten it down.

[Garufa]

Screw the buffer tube in as far is it will go with the detent retaining it freely then tighten the castle nut.

[Guest TnTnTn]

Thanks for the fast response. After looking at it I figured screwing the tube in a bit more would fix the problem. Will have to get a wrench now but probably need one anyway. TTT

[mikegideon]

And when you're done, stake your castle nut. You can use a spring loaded center punch. Look for videos on the web.

[Guest TnTnTn]

Update-after more research and inspection I see that the buffer is hitting the retaining pin as evidenced by deformity of the metal on the buffer. That is what caused the buffer pin and spring to eventually pop out. So................ I removed the pin and spring completely and the rifle runs fine-just have to control buffer and spring during takedown. As I understand the buffer is NOT supposed to hit the retaining pin when cycling-just as a retention feature when rifle is opened. I filed a relief cut on the buffer so that when I get a wrench to remove the stock, replace the buffer retainer and spring, screw the re in one turn the buffer will bottom on the rear of the bc before hitting the retaining pin. Work in progress but my favorite lightweight calling rifle is running in the meantime. TTT