My 500A2 wears a pac-nor 1-14 barrel. I have done some shooting with a 550gr cast,FWFL,no GC over 110grs H870 and found no leading. Plinking rounds...
45nut

As I recall the 500 A-sq uses a relatively fast twist, 1-10, which will likley limit your max velocities w/o leading. A gas check will certainly help though.

Thanks for the repl.gents.
This mould does not have a G.C. (G.C. in 50 cal are hard to come by here)and I was able to drive the bullet up to 1900 or so but like you guys only with slower powder I used 7828 and a filler.
This gun also has a 1:14 Pac Nor on it.
I am happy with the acc. of the XMP load but I can't go faster with this powder even with paper patch it rips the patch and leaves lead in the barrel.
To use the slower powders sort of defeats the purpose be cause it takes 100 or so gr per round.

Martin