4500/3000 is the PSI inside the tank, higher PSI means more air, in the same space = more shots. The regulator is what determines HP vs. LP. It's usually recommended cockers go with HP because you can bget shootdown with a LP tank.
Get a 70ci with a red (hp) reg.
MecTurtleCocker (8:51:28 PM): you just had to sig me, didnt you..