Steve, your gun was originally shipped with a magazine that had only ONE slot down the side, later, when they came out with the A-100 frames, they reversed the side the bottom for the mag follower, and moved it to the "other" side, this required another slot, so those mags have two slots, one on each side........to make this newer mag fit the older A-54 (your gun) you need to push down the follower of the magazine so the button lines up with the small hole ( enlarged part of the slot, near the bottom...holding the follower in this down position, pull out the button, and put it in to the other side, now it will fit your gun (A-54)....reverse as needd....bottom line you can put an A-100 magazine into your gun but NOT the other way around.......
now along comes the Mark II mags, having a "plastic" removable bottom ,held in place by a plunger (small hole in the bottom of the magazine) depress this plunger, slide the bottom off to the front ( or is it rear??? carefull not to put your eye out as the spring ( in this case of the new mags, it is a round spring, NOT a zig-zag that fits down inside the older ones........lower the follower, to the hole, in the side, remove the follower button, put in to the opposite side, and now this newer, new mag will also fit your A-54 frame?? got it?? easier to do than try and say and my bet is its on youtube someplace,,,,,,,,,,no links, I don;t go there..................most informed experienced, gun shops, or any gunsmith can and will show you how. Very quick, simple, easy to do.....................
