I picked up a used 15/22 yesterday and noticed that the rear takedown pin is in backwards. The mushroom-head is on the left side, so it has to be pushed out from the right side of gun.
It can be easily pushed for about 1/8", and then it doesn't want to move any further. I tried a mix of prying up on the mushroom-side and using a small hammer and a pin punch on the small side, but that only got me about another 1/16"
I could always use more force and a bigger hammer, but I'd rather not mess things up.
Anyone have any suggestions? The front pin is on the correct side and works just fine.
I'm thinking that the problem may have to do with whatever normally keeps the pin from being totally removed from the lower receiver, but that is just speculation on my part since I don't have another gun to look at.
Any suggestions would be much appreciated. The rifle appears to have been made in August 2010 and has a DUUxxxx serial number.