I've recently put my money down on a pre-ban olympic that has been altered.  The break-down pin in the back of the receiver has been swapped with one that is not stock and doesn't look like it should be on that rifle.  I talked to the owner of the shop about it and he suggested that I could remove the pin by REMOVING the buttstock and taking the pressure off the pin from the rear through the recoil assembly.  This makes no sense to me whatsoever.  He said that the pin is notched and it will not come out by simply pressing on it.  A friends very old AR's pin comes out with relative ease (just a push from the opposite side and it's out).  I don't see anyone removing their buttstock to remove the break-down pin.

HELP!  This is my first AR and I am very confused now.

For the rear takedown pin, do the fol:

1. Separate the upper form the lower.

2. Remove butt retaining screw from the lower (if its an A2 there will be a spacer inside the butt assy).

3. Remove butt assy.

4. You will notice a tiny spring protruding on the rear of the lower, remove it, and gently tap the return spring tube on something solid, and the detent should fall back (or out), (be careful not to loose it) so the takedown pin can then be removed.

5. On assy, do the reverse, paying attn to the slot in the takedown pin. It must line up with the detent. Be careful you don't mangle the spring when putting on the butt stock assy. The detent goes in pointy end first.

The AR is an armourer friendly weapon. Just go slow, and pay attention to detail. Its a simple job, and you should have no problems. Just takes a few minutes. Hope this helps you out.