9mm leading

[bdixon]

Hey Guys, first post here.

I just cast a bunch of boolits with the Lee 356-120-TC Mold to shoot out of my Sig P239 (9mm). The boolits were dropping out of the mold at .359-.360. I pan lubed them with the parrafin/vaseline/STP lube then sized them in my lee .357 sizer. I have slugged my barrel and it did come out to be .356", so I think .357 is a good size.

The problem I'm having is there is some lead building up towards the end of the barrel. From reading around, it sounds like the lube is running out too soon. It seems strange that Lee would put out a mold that doesn't have a big enough lube groove. Does anybody have any ideas I could try? This might be a dumb question, but would a beeswax based lube work better/last longer while the boolit is in the barrel? I would love to get this mold working rather than buying a different mold...

Thanks for your help.

[chris in va]

FWIW I had a bad tumbling/leading/inaccuracy issue with the 124gr TC TC boolit out of three different 9mm's. A different mold sized to .003 over slug fixed the issue. If your mold is reliably dropping .359, I'd try shooting those as your barrel measures .356.

[prickett]

Hey Guys, first post here.

I just cast a bunch of boolits with the Lee 356-120-TC Mold to shoot out of my Sig P239 (9mm). The boolits were dropping out of the mold at .359-.360. I pan lubed them with the parrafin/vaseline/STP lube then sized them in my lee .357 sizer. I have slugged my barrel and it did come out to be .356", so I think .357 is a good size.

The problem I'm having is there is some lead building up towards the end of the barrel. From reading around, it sounds like the lube is running out too soon. It seems strange that Lee would put out a mold that doesn't have a big enough lube groove. Does anybody have any ideas I could try? This might be a dumb question, but would a beeswax based lube work better/last longer while the boolit is in the barrel? I would love to get this mold working rather than buying a different mold...

Thanks for your help.

I'd try a .358" bullet. I'm not sure I buy the whole "running out of lube" suggestion. I quit "running out of lube" when I went to a larger bullet.

[epj]

Lead build up at the end of the barrel may indicate excessive velocity for your alloy/lube combo.

[bdixon]

Thanks for the suggestions. That will give me something to experiment with.

[gefiltephish]

Maybe my experience will be of some value to you, but keep in mind I've only been involved with this for a year now.

I've cast and shot about 3,000 or more of those same boolits over the past year. I too have always thought the lube groove was rather skimpy. My XD9 barrel gets leaded from breach to muzzle. Conventional lubing reduced the leading considerably compared to tumble lubing, but not to an acceptable level (to me). The barrel slugs to .3555. I've tried up to .358 without satisfaction, however I had to tumble lube those as I did not have a .358 die for the 450. Oh yeah, mostly air cooled ww. I have also tried 50/50 range lead/ww.

One observation is that the leading seems to be heaviest on one of the groove edges. Perhaps that's the leading edge, I'm not sure. So, I'm beginning to think "skidding". I now use WSF at a middle-of-the-road charge of 4.4. I have used up to 4.6 as well (4.7 is max). 231, Unique and TG did not make any noticeable differences. We shall see...

This past week, I cast up 2 batches (ww) with the new Mihec 124hp mold. Nice looking boolits! Mine actually weigh about 128gr. The lube groove is definitely larger than the Lee. The first batch is air cooled, and the second is water dropped. I lubed them in the 450 with a new .358 die. I'm going to let them age about 2 weeks before testing.