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.

if you take the grip handle off slowly, the rear takedown pin spring and detent pin will also come out (along with the safety spring and detent pin). The takedown pin should easily slide out. Then put the rear takedown pin in its correct position and reassemble the grip handle (with both springs and detents) and you should be good to go.

See the sticky videos for changing grips and trigger groups to understand the takedown pin springs and detents.

Good luck

M&P 15-22 Instructional Video Series

Follow the link above to see all of my instructional videos.

Watch the video on how to remove the grip. There will be a pair of springs and a pair of detents in the receiver/grip. The detents go on top of the springs, pointy side up.

Thanks very much.

Just to make sure I had the detents in the right places, the smaller diameter shiny one goes with the takedown pin spring, while the other detent is larger diameter, black and has a small lip near the bottom end.

Made the takedown pin removal and re-install very easy.

Thanks!!

The bare metal colored detent is for the safety selector, the black detent is for the take down pin.

Thanks again!

Any time! Glad the video helped out.