Powdercoating removed by rifling (leading)

[Alexander94]

Hi,

I have a problem with the pc being stripped off by the lands in the rifling.
In the attached pictures the bullet on the left is sized to .357, the one in the middle is pounded through the barrel and the right one is shot into water.

I have tried the shake n bake method but couldn´t get the powder to stick at all. So i use an es gun to apply the powder with the bullets standing on a tray. (pictures)
400degrees for 20 minutes, passes the hammer test with absolutely no flaking.
accuracy is good (group in the picture is from 28 yards)
The leading only occurs on the lands in the rifling.

0.357 is the largest i can get away with without broatching the throat.

I was really happy with how to loads peformed untill i realised the pc was being removed.
In the beginning i had a problem with the bullets being swaged down by the case, i made a new longer expander plug and the problems were gone.
I dont think there´s a sizing isssue since the pc is only removed where the lands contact the bullet.

Any tips on how i can solve this problem is welcomed.
// thanks

Info:
gun - cz85combat 9mm.
barrel dimensions - slugged to .356
lead alloy - 50/50 ww/pure lead and 2% tin/pewter measured hardness of around 10bhn
bullet - lee 120tc 6 cavity sized to 0.357 after pc. drops at 0.3578 from mold.
powder - vihtavuori n330 at 4grains.
velocity - 1010fps
OAL - 1,051

[dkonrai]

Is the base coated? That might be the issue?
I've shot alot of pc boolits. I get streaks in my Glock due to the rifling but not much just slight.
I run 358 and no leading in a 686.

Sent from my A7 Pro using Tapatalk

[JM7.7x58]

Sharp throat? Or almost no throat?

[Alexander94]

The barrel is a stock cz with minimal throat.
Max oal is 1,065. It seems that the bullet contact the taper in the throat before actually touching the rifling.

[Alexander94]

Is the base coated? That might be the issue?
I've shot alot of pc boolits. I get streaks in my Glock due to the rifling but not much just slight.
I run 358 and no leading in a 686.

Sent from my A7 Pro using Tapatalk

Since i use the stand up method and es gun the base remains uncoated.

[Conditor22]

The base does not need to be coated.
How long and how hot did you bake them (200 C?)
Did you try smashing one to see if the powder stayed on?
Did you shoot both the second and third boolit?

[Alexander94]

The base does not need to be coated.
How long and how hot did you bake them (200 C?)
Did you try smashing one to see if the powder stayed on?
Did you shoot both the second and third boolit?

200celcius for 20 minutes. As mentioned in the post they pass the hammer test, even after pounding the bullet sqaure from all 4 sides the pc is intact. The second bullet is pounded thrue the barrel using a brass rod to check for pc wearing off.

[Petander]

The second bullet is pounded thrue the barrel using a brass rod to check for pc wearing off.

In that case,doesn't that look a bit undersize?

[Alexander94]

In that case,doesn't that look a bit undersize?

Hard to tell from the picture. measures 0,357 after sizing. Largest measurment of the bullet after being driven through the barrel is 0,356.
So it shouldn't be undersize.

[Conditor22]

Welcome to cast boolits Alexander94, I saw you were from Sweden but didn't notice your post count.

if you can't go larger, go harder. Maybe quench after Powdercoating with those boolits (put some of those boolits back in the oven and bake for 30 min at 200C then drop them in cold water right out of the oven.

Is that 200° for 20 minutes in a preheated oven

[Alexander94]

Welcome to cast boolits Alexander94, I saw you were from Sweden but didn't notice your post count.

if you can't go larger, go harder. Maybe quench after Powdercoating with those boolits (put some of those boolits back in the oven and bake for 30 min at 200C then drop them in cold water right out of the oven.

Is that 200° for 20 minutes in a preheated oven

Thank you, i wanted to get away with the softer alloy since i have alot of pure lead. And almost all wheel weights here are zink. So a 50/50 reduces my ww amount greatly.
Forgot to mention that i water drop the hole pan directly after oven. If i let them aircool i lose 1-2bhn. Yes preheated.

[Conditor22]

If you can't go harder, you will need to either go slower or try to go bigger or get a 9mm mold with a gas check.

Can you get linotype there? it's a great hardener.

[Alexander94]

If you can't go harder, you will need to either go slower or try to go bigger or get a 9mm mold with a gas check.

Can you get linotype there? it's a great hardener.

Hmm, one of the main reasons for casting my own bullets is the price, will be using them for ipsc practice and competition, minimum powerfactor for minor is 125. So i need to push them to 1050fps minimum. Maybe it's not possible with as soft alloy. Linotype is not so common anymore. The EU is on the way to to ban lead from everything here.. including hunting ammunition.

[Conditor22]

Last resort, several people have had success casting zinc bullets if you use a steel mold

Cast Zinc Bullets (223) Loading, Shooting, Capturing!!
https://www.youtube.com/watch?v=xJJ4...nnel=elvisammo

[Idz]

I use range scrap (bhn~9) and had leading problems with 9mm Lee 356-125-2R PC with HF red. What solved my problems was 1) PC twice (easy if you use the basket method) 2) size to 0.357 after PC 3) expand case mouth with a homemade M-die punch that is 0.359 diameter which yields a 0.357-0.358 case mouth ID after springback. My punch is inserted into the case about 0.15" deep so bullet drops into case below lube groove. 4) use seating die only for seating and use a Lee FCD for crimping case. My cartridges fail a case guage but chamber beautifully. I think the soft alloys get crushed too much if used 'properly' and the bullet would cock slightly and scrape off PC unless dropped deep into the case.

[Doughty]

Alexander94,
A few questions:
Are you getting lead deposits on the lands in your barrel?
Have you measured the BORE diameter of your barrel?
Have you / do you shoot jacketed bullets in your barrel?
Approximately how many total rounds through your barrel?
Do you have any possibility of using a borescope to examine your barrel?

[redhawk0]

One thing you haven't mentioned....are you getting leading in your barrel? If not...there might not be anything to worry about.

redhawk

[Loudy13]

if you can not get the powder to stick at all trying to shake them I believe that is one issue I have not had any bullets ever that wouldn't take a coating using shake and bake. Maybe you have some contamination somewhere in your process that is adding an oily substance to your cast boolits. Do you water drop when you cast? I had not cleaned my bucket that I was quenching with for a few sessions and I had a batch of bullets that would not hold the pc. They would coat and pass the hammer test and size just fine but then I would be able to scratch the coating off with my fingers. And they did cause leading. It was very confusing since I was doing the exact same thing I always had done. I wash my quench bucket now with dishsoap and hot water before each session and have not had the issue again. Just my 2 cents from a lesson learned.

[Alexander94]

One thing you haven't mentioned....are you getting leading in your barrel? If not...there might not be anything to worry about.

redhawk

Yes im getting a small amount of leading, but only on the lands.

[Alexander94]

Alexander94,
A few questions:
Are you getting lead deposits on the lands in your barrel?
Have you measured the BORE diameter of your barrel?
Have you / do you shoot jacketed bullets in your barrel?
Approximately how many total rounds through your barrel?
Do you have any possibility of using a borescope to examine your barrel?

Yes only on the lands, if you look at the bullet to the right in the pictures you can see that the PC is completely removed from were the lands engage. Bore diameter is 0,348.
Yes i shoot jacketed, a guess would be around 8k through the barrel. Unfortunately i don't have acces to a scope..