So I did some measuring along with some math and discovered my new non-ported shs cylinder to stock (9.5inche) inner barrel volume ratio is 3.2:1. I realize typical ratios are generally between 1.5:1 and 2:1, with the cm16 stock shorty being 1.62:1. On the 1.62:1 ratio with m130 spring and 0.20g bb's I'm shooting 390 FPS. When I get more money I am planning on getting a 9inch mock silencer and popping in a 469mm tight bore barrel. That will drop the cylinder to barrel volume to 1.69:1 ratio but until then I am wondering what weight BB should I use to get the best usage of energy ... 0.28, 0.30, 0.36, higher?? Thanks for the input guys. If anyone is wondering how I came to this conclusion or how I did the math please feel free to comment. I didn't want to post too much info right off the bat.