One of the questions you have to ask yourself is, "Do you really need 300 bar pressure?" If you do not, where your PCP gun works fine at 230 bar or less, you do not need a CF bottle. SCUBA tanks and equipment are much less expensive than SCBA equipment. As I have stated before, high pressure air HPA is the most expensive element of our sport. I honestly believe if you stay in this sport long enough, everybody will eventually acquire a commercial compressor because it is better and less expensive in the long run. That said, bottle volume is more important than bottle pressure. A 12 liter SCUBA aluminum bottle will allow me to shoot all day at the gun range with my FX Crown. I charge these to 230 bar. It also allows me to shoot my PP700SA pistol every day for a month before recharging the 12 liter bottle. Another cost saving solution is a steel 40 liter bottle if transportability is a non-issue. I get 40 shots per gun fill with my PP700SA. I have a 12 liter CF bottle as well, but I use that for portability and with my two GK1s, which I charge to 300 bar. However, these large volume bottles cannot be recharged with these mickey mouse Chinese compressors. I have a 80 liter Bauer, 4 cylinder compressor I found in the junk yard for $150 which I rebuilt.