Powdercoat sizing question

chris in va · November 1, 2023, 12:20 AM

I've cast and sized many thousands of bullets the past few years. I just got a new 9mm mold, drops at .358. I have 355 and 357 sizing dies.

It occurred to me that if I use the 357 die on the bullets first, then post size the PC at 357 again the coating might get too thinned out. Is it better to 355 first then 357 after coating?

mehavey · November 1, 2023, 05:34 AM

In my experience/practice, PC 1st, then size after curing.
From 223 to 50 BeoWoof -- and all the pistols in-between -- never any adverse issues

Recycled bullet · November 1, 2023, 05:36 AM

Size them once after coating. If the force is excessive clean the bullet sizing die with a brass barrel brush and lightly apply lubricant to the powder coated bullets and size them all at once.

My preference is 357 it functions 100 % in my guns 38/357/9x19.

chris in va · November 1, 2023, 04:41 PM

Ok so the bullets drop at 358, so PC and size at 357? I'm not sure there will be any coating left.

Recycled bullet · November 1, 2023, 04:47 PM

If the coating is coming off of your bullets as you're sizing them, then there is a fundamental flaw with adhesion going on.

You should be able to take a powder coated pistol bullet place it upon a steel plate and hammer it into a lead coin and the coating should not chip off anywhere.

Recycled bullet · November 1, 2023, 05:23 PM

This is an MP359HAMMER with the deepest hollow point, powder coated with a light blue.

I took the bullet and placed it upon the anvil on the back of a shop vice and hammered it with a 4 lb sledge until it is flat.

The metal has experienced a structural failure those are the cracks or splits on the sides. The coating remains intact everywhere where the metal has not broken.

reddog81 · November 1, 2023, 07:45 PM

Recycled bullet is correct. The coating will stay on unless the PC didn’t cure correctly.

Sizing multiple times isn’t going to help much unless trying to shrink diameter a bunch like going from a .45-70 bullet at .460 to .452 for 450 Bushmaster. Even then it’s not really a great idea but better than doing it in one pass.

chris in va · November 1, 2023, 08:39 PM

I crushed one flat, didn't notice any flaking off, just where it thinned to the metal from the hammer and concrete. I'm mostly concerned about the PC being too thin for the rifling, that's why I sized to 355 first then 357 afterward. If I cast and PC it comes out at 360, so sizing down to 357 might be a stretch.

I haven't posted pictures in years, what are you guys using these days?

mehavey · November 1, 2023, 08:53 PM

Quote:

what are you guys using these days?

For pictures... or PC ?

postscript: a 0.360" PC'd bullet subsequently sized to.357 is no problem at all
(in fact it's what I routinely do for my 9mm's)

reddog81 · November 2, 2023, 12:33 AM

Sizing .003 is common. What makes you think there’s a problem? If you have the sizing dies can’t you just run a bullet through it and see what happens?

November 1, 2023, 12:20 AM	#1
chris in va Senior Member Join Date: December 26, 2004 Location: Louisville KY Posts: 13,806	Powdercoat sizing question I've cast and sized many thousands of bullets the past few years. I just got a new 9mm mold, drops at .358. I have 355 and 357 sizing dies. It occurred to me that if I use the 357 die on the bullets first, then post size the PC at 357 again the coating might get too thinned out. Is it better to 355 first then 357 after coating?

November 1, 2023, 05:34 AM	#2
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,898	In my experience/practice, PC 1st, then size after curing. From 223 to 50 BeoWoof -- and all the pistols in-between -- never any adverse issues

November 1, 2023, 05:36 AM	#3
Recycled bullet Senior Member Join Date: November 13, 2022 Posts: 342	Size them once after coating. If the force is excessive clean the bullet sizing die with a brass barrel brush and lightly apply lubricant to the powder coated bullets and size them all at once. My preference is 357 it functions 100 % in my guns 38/357/9x19.

November 1, 2023, 04:41 PM	#4
chris in va Senior Member Join Date: December 26, 2004 Location: Louisville KY Posts: 13,806	Ok so the bullets drop at 358, so PC and size at 357? I'm not sure there will be any coating left.

November 1, 2023, 04:47 PM	#5
Recycled bullet Senior Member Join Date: November 13, 2022 Posts: 342	If the coating is coming off of your bullets as you're sizing them, then there is a fundamental flaw with adhesion going on. You should be able to take a powder coated pistol bullet place it upon a steel plate and hammer it into a lead coin and the coating should not chip off anywhere.

November 1, 2023, 05:23 PM	#6
Recycled bullet Senior Member Join Date: November 13, 2022 Posts: 342	This is an MP359HAMMER with the deepest hollow point, powder coated with a light blue. I took the bullet and placed it upon the anvil on the back of a shop vice and hammered it with a 4 lb sledge until it is flat. The metal has experienced a structural failure those are the cracks or splits on the sides. The coating remains intact everywhere where the metal has not broken.

November 1, 2023, 07:45 PM	#7
reddog81 Senior Member Join Date: October 16, 2014 Location: Iowa Posts: 1,635	Recycled bullet is correct. The coating will stay on unless the PC didn’t cure correctly. Sizing multiple times isn’t going to help much unless trying to shrink diameter a bunch like going from a .45-70 bullet at .460 to .452 for 450 Bushmaster. Even then it’s not really a great idea but better than doing it in one pass.

November 1, 2023, 08:39 PM	#8
chris in va Senior Member Join Date: December 26, 2004 Location: Louisville KY Posts: 13,806	I crushed one flat, didn't notice any flaking off, just where it thinned to the metal from the hammer and concrete. I'm mostly concerned about the PC being too thin for the rifling, that's why I sized to 355 first then 357 afterward. If I cast and PC it comes out at 360, so sizing down to 357 might be a stretch. I haven't posted pictures in years, what are you guys using these days?

November 2, 2023, 12:33 AM	#10
reddog81 Senior Member Join Date: October 16, 2014 Location: Iowa Posts: 1,635	Sizing .003 is common. What makes you think there’s a problem? If you have the sizing dies can’t you just run a bullet through it and see what happens?