I agree with what the others have already said. FX barrels love the JSB 25.4's and the 33.95's. The 25.4gr are super accurate, usually better at shorter ranges(to 75yds) and give you the best velocity. The 33.95 MkI or MkII will be super accurate too, not as fast but definitely ballistically superior at longer ranges (out to 150yds or more). My gun also shoots most of the H&N pellets very well too, but when it comes down to phenomenal accuracy, the JSB's are usually the way to go! Stoti