OK, bought some goodies from HomeDepot. A 3/8 od 1/4 L nylon spacer (hole was .177, but will drill this larger), a 5/16 dia 2" L nylon bolt that has about 1 1/2 non-threaded shank and a 1/8 dia tension pin. Cost me $1.50. The 3/8 spacer fits perfect in the spring channel of the mag and the 5/16 bolt guides the spring perfectly. I inserted the spacer, spring and follower in the mag and started loading rounds. It held 12 & the 13th almost fit, so I sanded the spacer down to a 3/16 L and got 13 in there with just your typical extra push down of the follower. The spring compresses to 7/8, so I did some math and the spring guide part of the plug should be approx 11/32 and will get the spring compressed to around 1" with the followers spring guide not touching the plugs spring guide. I reamed and threaded the id of the spacer for the thread end of the bolt, twisted the bolt in nice & tight, cut the protruding thread from the bottom of the spacer, cut the top of the bolt so 11/32 L is left, tapered the bolt like the original plug for proper spring guiding. I then drilled a slightly smaller than 1/8 hole for the tension pin in the bottom of the assembled plug, pressed it in and cut it to length like the original plug. Assembled all the mag components and made sure 13 still fit and compressed the spring properly. Flipped the rounds out with my thumb to make sure the follower rose correctly. All is well. There seems to be OK spring tension near the last rounds, so I will test it next range time and let you all know. I'll get pics up today. One thing I should mention, there were no mods done to the original AA mag parts, so it can be returned to its original factory state if needed. If more than 13 are desired, well that's a differnt story and mods to the follower would be in order. I'm fine with 13. Also, the extra 3 rounds are not seen in the mag body viewing slot, but the slot can be dremeled longer if you take care not to cut into the guide rails just behind and close to the viewing slot.