9mm casting for poly rifling

[matthewquigley]

ok
i am needing help i have a baby eagle with polygonal rifling thing drives tacks with them other kind of boolits ( copper) if i cast some 140 grain 357 slugs and size to 358 dia will it be ok? i am sure i read an article about heavy 9mm boolits and them being over sized shooting well out of poly rifling
i have casted for a bit for other calibers 45, 44 357 50 but these poly bores WILL NOT shoot :killingpc a 355-356 dia at all i might as well throw rocks!

any ideas or help would be great!

[Gunslinger]

I have been struggling to eliminate leading in my poly 9mm for quite some time now! It has been a long journey and has taken me about 1000-1200 rounds! The leading is not eliminated but is now at an acceptable level!

First and foremost you need to slug your bore. I shoot a .357 boolit in a .356 bore. Sometimes .002 over bore is too much in a 9mm, and the rounds won't chamber. But by all means if you can chamber a .358 then you can shoot it.

Casting for 9mm is tricky but what I've read and what has worked for me is heavy bollits and low velocity. I shoot a 130gr RN boolit with 3.5gr of VV N320 - don't know the velocity though. You can find an american equivalent if you look at a burn rate chart. Bare in mind that fast powders are more likely to lead than sower powders are... at least that's what I heard... and I had to go lower than minimum charge to eliminate severe leading with the N320.

Ohh... and don't crimp too much.

Good luck....

[bobthenailer]

i have a kahr pm9 with poly rifling i use a saeco 122 gr tc , ww water dropped and sized to .357 at 950 fps , with no leading problems and i usually shoot 50 to 100 at the range . but do keep a eye on lead build up!!!!! every gun is diffrent

[finishman2000]

my poly Kahr leads as well. it does clean out very easily though.

[fecmech]

I had a Khar MK 9 That I shot about 3500 cast rounds through, mostly 121 Lee tc water dropped WW. Most of what I shot was that bullet at a little over 1100 fps and 147 Kead cast at 950 fps. I had some light streak leading that did not build up( one shot would leave a light streak and the next would take that streak out and leave one behind etc.). Accuracy was reasonably good for a stock auto with groups running between 2 and 3" @ 25 yds. My bore was .355 as near as I could measure and I sized to .357. I think the poly thing is way overblown, at least from my Khar experience.

[thx997303]

When you slug the bore, you measure on the groove diameter right?

[Nate1778]

I have not had any luck with cast in my G19. I get an acceptable amount of leading but still not enough for me to be comfortable to not look down the barrel every clip or so.

[finishman2000]

I have not had any luck with cast in my G19. I get an acceptable amount of leading but still not enough for me to be comfortable to not look down the barrel every clip or so.

i ended up putting a lone wolf barrel on my g-34 just because i shoot almost all lead now.