9mm boolit size

[Blkpwdrbuff]

Hi guys,
I just slugged the barrel on my son in laws HKP30.
I has polygonal rifling.
The slugs mike out at .355. I usually size .002 over but am unsure with the polygonal
rifling.
Any opinions, experiences?
This is a new area for me.

Thanks in advance.
Blkpwdrbuff:castmine:

[Edubya]

Try out one of the fired brass. Will the 357 fit into it without shaving lead? I would try a little larger if it will chamber. The polygonal rifling should not make that much difference. Start low, work up as always.
EW

[d_striker]

Although I have heard of a few people that shoot lead out of their stock glock and H&K barrels w/o any problems; I thought cast lead was bad for polygonal rifling. Or should I say polygonal rifling is bad to shoot cast lead out of.