If you were to make your GBB magazines tapped for HPA lines and you wanted to do it yourself, then this is the tool that you would need. How this tool would be used:- First you would need to drill the hole into your GBB magazine using an "R" Size Drill Bit (Actually .3390". 11/32" is the closest fraction (.3437).- Then you would need to run this tap through the hole, what that would do is add threading to the hole in order to make it so that you could mount the fitting directly to your magazines. - THIS IS ONLY RECOMMENDED FOR VERY EXPERIENCED PLAYERS, AND AMPED IS NOT RESPONSIBLE IF YOU DAMAGE YOUR MAGAZINES.
