. i was taught over 23 ftlbs , and true magnums are .22 and .25 . i had to adjust my own personal criteria down to 21 ftlbs, so that it may include .177 . youre looking at 950 fps in .177 with crosman premier heavies (10.5 gr) and 820 fps in .22 with crosman premiers (14.3 gr) and 680 fps in .25 with ftt pellets (20 gr) . i also consider the weight of the rifle (8.5 lbs and over) and sometimes recoil and cocking effort. i've had several diana 48's. untuned, broken in d48's generally produce 18-19 ftlbs in .177 , 23 ftlbs in .22 , and 20-21 ftlbs in .25 - yet we all know this is a magnum. the r1 and np2 rifles are just on the cusp of being modern magnums. the first airgun i know of to called a 'magnum' was the fwb 124 , which as mentioned above is barely over 13 ftlbs. now that we have .30 cal , i'm sure it will evolve again. hope that helps. - raneman.