View Full Version : AR assembly question

08-28-2009, 9:54 AM
I'm putting together my first AR. I'm attaching my collapsible stock to the lower receiver. I put in the rear takedown pin with the grove facing the rear, I put in the rear detent pin and the rear detent spring and finished putting the stock together. The problem I have now is the rear takedown pin doesn't budge for me to attach the upper to the lower. I've read that it should still slide in and out. Did I do something wrong, am I missing something?

08-28-2009, 10:06 AM
Just stiff? If the detent is in the groove properly, you *should* be able to push out the pin. Sounds like you did it correct.

08-28-2009, 10:19 AM
Use a punch and light tap it. Add a couple drops of clp, gun oil, lube to ease it through.

08-28-2009, 10:35 AM
They can be a bit tight when new. With mine, I made sure both the takedown pin and detent pin were coated in a light film of oil, I then put a bit of thicker lube (tw25b grease) in the detent pin groove of the takedown pin. With some pressure and light wiggling hopefully it should budge.

08-28-2009, 11:19 AM
I bought an ambidexterous safety for my MMG, Varmiter build and it really caused some binding. Sometimes parts are a few thousandths over spec, here and there.

If you can get some lapping compound, put some in there and work it a few times. Otherwise, just give it a while to "wear-in"...

08-28-2009, 11:21 AM
I thought the same thing when I built mine and I took it all back apart back together. With the same results I put lube on it both times and it was stiff but a punch with tape on the end (so it won't scratch) tap it out and in a few times and it will get better. Let me guess CMMG lpk?

08-28-2009, 12:41 PM
yep, cmmg

08-28-2009, 1:43 PM
It will loosen up after shooting it for a while. Is it a RRA lower? They are notorious for being a tighter fit.

08-28-2009, 2:08 PM

I was worried as well, I did all the "fixes"...lube working the pin w/ a nail punch etc...

After i put a few rounds down the pipe, I was able to push the pin w/o the aide of a punch.