I have a completely empty ICS Split GB shell that I want to build. I am looking to make a DMR out of an M16 shell. For the ICS people, what would be the best way to go about doing this? Looking for input on internals to use to have a long lasting rifle that will be a "counter sniper" *Edit* I forgot to put down desired FPS. around 530 with a .20, the max is 550 with a .20 so just to be safe. I will be using .25, .28 or .30 depending on testing after the build.