Never had a gun with a barrel other than 20 inches in the 2520 days. I won't use AA due to lot to lot variation was so damn horrible years ago. John says thats all over now... so I"m a bit more at ease since I need to try a couple of AA powders for specific things, but I still dont' like the idea... 10mm and 200/220 hard cast and something to cycle the short 16 inch 300/221 AR with 194s or 115s... So I guess I'll see eventually.
But 2520 and 20 inch rifle, rifle gas, various port sizes actually, standard and M16 carriers of the day, standard buffers, bullets from 60 to 80 grains never had a cycling issue.
