Sizing 9mm to...?

Helka

Helka

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Good afternoon nutters.

So i'm going down the rabbit hole in starting to cast my own bullets. I have a bunch of supplies coming from higginson's and i just ordered the MP Mould 4 cavity HP 359-125gr.

My question is, i'm looking to PC the hollow points. What bullet sizer diameter should i get? 356 or 357 or...?

Will be shot in both my CZ's Shadow 2 and p-10F.

Thanks
 
The old rule of thumb rule is to slug the bore to figure out what your bore size is, and then add 1 - 2 thou. For example is your slug comes out at 355 you could use a cast bullet sized to 357 dia.
 
True 9mm bullets are supposed to be .356, a thou over a standard .355 barrel. If you don’t take care when rifling a 9mm barrel & it comes out to .356 or .357, then standard .356 bullets will tumble.
9mm barrels must be .355. Your .359 mold is way too big, more like a .358 38special bullet….I suggest you obtain a six (6) cavity LEE 9mm mold like their best mold, # 90457 from my pals @ Higginson powders.
 
hatman1793 said:
True 9mm bullets are supposed to be .356, a thou over a standard .355 barrel. If you don’t take care when rifling a 9mm barrel & it comes out to .356 or .357, then standard .356 bullets will tumble.
9mm barrels must be .355. Your .359 mold is way too big, more like a .358 38special bullet….I suggest you obtain a six (6) cavity LEE 9mm mold like their best mold, # 90457 from my pals @ Higginson powders.
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I have that 6 cavity coming from them on Friday.

I slugged both my 9’s. The shadow is .355 the p-10f is .3545 so I may stick with 356 sizer

As for the 359 mold is states can be sized down to 356. It’s from MP molds.
 
357

The best results I've had are with molds that drop large like 358 and size to 357. My favorite is a LEE push though sized that I spun to .3575. The sizers often come slightly undersized.

You want that lead to smash into those grooves. Make a better seal. Leading isn't a problem with properly sized and adequately lubed/coated bullets.
 
redruns said:
357

The best results I've had are with molds that drop large like 358 and size to 357. My favorite is a LEE push though sized that I spun to .3575. The sizers often come slightly undersized.

You want that lead to smash into those grooves. Make a better seal. Leading isn't a problem with properly sized and adequately lubed/coated bullets.
Click to expand...

Thanks for the info
 
A nine with a snug throat can cause problems with powder coating. The PCing adds a couple of thou to the throat area, and bullets may have to be seated too deeply because the sizing die won't touch this area. I have had to use a throat reamer on two barrels to remove a whisker from the throat. This would allow clambering with a proper length round.

Accurate Molds makes a 9 mm. design whereby the diameter is reduced by about two thou immediately before the case mouth. This is to accommodate the PC. It works well for me.
 
slug said:
A nine with a snug throat can cause problems with powder coating. The PCing adds a couple of thou to the throat area, and bullets may have to be seated too deeply because the sizing die won't touch this area. I have had to use a throat reamer on two barrels to remove a whisker from the throat. This would allow clambering with a proper length round.

Accurate Molds makes a 9 mm. design whereby the diameter is reduced by about two thou immediately before the case mouth. This is to accommodate the PC. It works well for me.
Click to expand...

Ok. The MP mold I’m getting is specific for PCing. Hopefully it works.
 
If your mold throughs .359 slugs and you want to PC them and use at .357, I would suggest you plan on sizing your "as cast" slugs down to your desired "finished" dia. before PC'ing them and then you will have to size again after PC cooking. PC coating thickness isn't an exacting science at a hobbyist level, different powders, changes in the humidity in the air can change a thickness from .0015 to .003 from one cook to another. Your finished dia of slug & PC may very well be in the .361 or 2 if PC'd as cast.
The point I'm trying to get across is that a big "downsize" at one push will often scrub the PC off the sides of the carrier rings...best to uniform your slugs smaller beforehand.
 
fingers284 said:
If your mold throughs .359 slugs and you want to PC them and use at .357, I would suggest you plan on sizing your "as cast" slugs down to your desired "finished" dia. before PC'ing them and then you will have to size again after PC cooking. PC coating thickness isn't an exacting science at a hobbyist level, different powders, changes in the humidity in the air can change a thickness from .0015 to .003 from one cook to another. Your finished dia of slug & PC may very well be in the .361 or 2 if PC'd as cast.
The point I'm trying to get across is that a big "downsize" at one push will often scrub the PC off the sides of the carrier rings...best to uniform your slugs smaller beforehand.
Click to expand...

Thanks i will do that, noob question, can i push through non lubed cast buuelts or do i need to lube then take lube off before pcing
 
Helka said:
Thanks i will do that, noob question, can i push through non lubed cast buuelts or do i need to lube then take lube off before pcing
Click to expand...
Lee recommends lubing the bullets before sizing. However, I have been sizing my unlubed 'as cast' bullets prior to powder coating and have had no problems with lead smearing or building up in my Lee .356 push-through sizing die. I think as long as the die has a smooth interior surface lubing is not required. It might also be worth polishing the sizing die with some 0000 steel wool covered in fine lapping compound to smooth the surface without altering the die diameter. I just wrap enough steel wool to give a snug fit around a short length of wood dowel chucked in a drill. Seems to do the trick.

After the bullets have been sized I give them a quick swish in lacquer thinner to remove any residual oil they may have picked up in the casting or sizing process. It may be unnecessary but I'm a bit OCD. The thinner evaporates quickly and the bullets powder coat well so no harm done.
 
ted_dent said:
Lee recommends lubing the bullets before sizing. However, I have been sizing my unlubed 'as cast' bullets prior to powder coating and have had no problems with lead smearing or building up in my Lee .356 push-through sizing die. I think as long as the die has a smooth interior surface lubing is not required. It might also be worth polishing the sizing die with some 0000 steel wool covered in fine lapping compound to smooth the surface without altering the die diameter. I just wrap enough steel wool to give a snug fit around a short length of wood dowel chucked in a drill. Seems to do the trick.

After the bullets have been sized I give them a quick swish in lacquer thinner to remove any residual oil they may have picked up in the casting or sizing process. It may be unnecessary but I'm a bit OCD. The thinner evaporates quickly and the bullets powder coat well so no harm done.
Click to expand...


Thanks for all the tips.
 
I never lube a bullet that I plan on PC coating. The sizer press I have set up for PC bullets has been boiled clean of lube & has no contact with any lube or die that may have lube on it. I have a separate press with lube in the tube if i want to conventional lube some bullets...I think I have used it once since starting PC coating and that was just to get some "comparison" slugs for a rifle.

My own cast slugs or any "unlubed" ones i buy just get sized through the dry sizer and coated, I don't have to give them a bath beforehand.
 
fingers284 said:
I never lube a bullet that I plan on PC coating. The sizer press I have set up for PC bullets has been boiled clean of lube & has no contact with any lube or die that may have lube on it. I have a separate press with lube in the tube if i want to conventional lube some bullets...I think I have used it once since starting PC coating and that was just to get some "comparison" slugs for a rifle.

My own cast slugs or any "unlubed" ones i buy just get sized through the dry sizer and coated, I don't have to give them a bath beforehand.
Click to expand...

Good call on boiling the sizer. once i get it i'll do that!
 
Simply put, the largest size you can seat and chamber. Be warned, when powder coating, if your shake and baking, you increase the diameter of the nose of the bullets which usually requires you to seat them a little deeper. Most 9mm chambers have short, abrupt throats.
 
sawzall said:
Simply put, the largest size you can seat and chamber. Be warned, when powder coating, if your shake and baking, you increase the diameter of the nose of the bullets which usually requires you to seat them a little deeper. Most 9mm chambers have short, abrupt throats.
Click to expand...

I did read that on Cast Boolits, thanks for the reminder. Hopefully it all works out. Ordered my MP Mold on Tuesday morning from Slovenia and arrived this afternoon. 2 days to travel half way around the world. Same day purchased stuff from Higginson's in hawsbury, ON. Still waiting lmao.
 
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