just a point to note about lil gun in the 450... for projo's from 200-250gr or so - and some even a bit heavier than that - somewhere right around 38 grains seems to be a magic number. use 36 as a starting point and work up from there.
dont expect beautiful ES/SD numbers, but the accuracy should fall in there. its almost eerie every time someone finds another projo that shoots well with that load.
also rem 7½ primers seem to be the magic sauce, although i've had luck with cci 450's and even 400's with that load. no appreciable chrono difference between the 450 and the 7½ in two different guns ive got to play with them in.
taper crimp (hornady taper crimp die, not the lee FCD) to around 0.473-0.474 as close to the case mouth as you can measure without falling off.
cheapeast plinking bullet i've found is the 225 ftx. again 38 gr Lil gun, crimped to ~0.473 and a rem 7½ @ roughly 2.120" oal or so (right in the cannelure).
this also happens to be a VERY accurate bullet for the 450... if you cant get one of these to shoot...
Also... watch for blems/2nds to come on sale.. last batch i bought up a bunch of them was under $0.20/ea delivered. cost per round on these loaded for me is roughly $0.35 per squeeze.