Originally Posted by mrt949
Would It be legal to plug the mag ?
That would depend on the exact language of the state's statute, and the method used to plug it. Most jurisdictions with magazine capacity limits require that the mags not be capable of being converted to larger capacity. Thus, "plugs" would have to be solid and permanent.
The 10-round magazines that came with Para-Ordnance pistols during the Federal AWB (and I suppose what is still shipped to California and New York) were totally different from the standard capacity mags, having a tall, solid polymer base to which the 10-round steel body was attached. The height of the solid base varied depending on whether the pistol was a P10, P12, P13 or P14. The mag body itself didn't change.
Aftermarket Para mags had a dimple in each side and a score mark all around that cut almost
all the way through the metal. The score didn't touch the dimpled sections, which held the mag together and stopped the follower from dropping lower than 10 rounds of capacity. Drill out the dimples, and the first time you loaded 10 rounds the mag body would snap along the score line.