Go to Hennings website for parts and mags. You will find that he is an incredible person to deal with. You will learn that the comp you have needs a lot of gas to work properly. Auto Comp and AA#7 work very well with mine when loaded to major. I load to an over all of 1.170 with out any problems in the mags . I use the 9x21 barrel like yours and load 9x19. With over 12,000 rounds through it there have been no problems.