Leading with 10mm PC bullet...

[blueline541]

I've successfully loaded a variety of powder coated calibers, but I'm hitting the wall with 10mm.

I'm using a Lyman 175 gr. bullet with WW alloy, and I've used Harbor Freight red and Eastwood Ford light blue. The bullets are sized to .401, and I'm using 8.3 gr. of Longshot and keep getting a horribly leaded barrel. I recently order 100 180 gr. powder coated Bayou Bullets, and they leaded worse than my PC .bullets. Accuracy is great in my Glock 20 and 29, but they lead horribly.

Mine are sized to .401", but I didn't size the Bayou Bullets. I flare my brass enough to keep from sheering off the powder coat finish. I also measured a pulled loaded round to check for swaging. The pre-loaded bullet measured .400 the same as the pulled bullet.

I assumed it may be my homemade PC bullets, but the Bayou Bullets were worse than mine. Could it be the powder and/or charge? I don't want anemic .40 cal loads for my 10s, but this isn't working at all.

Thoughts or suggestions?

[djryan13]

Try pulling a few rounds to see how the bullets look after you seat/crimp. If you are scraping the coating off in that process, that is the culprit.

[Conditor22]

Do the PC'd boolits pass the smash test? Are you baking at the proper temperature (many ovens are off you need to check the temperature with a thermometer to assure the inside of the oven is reaching 400° for 25 minutes?

Try slugging the barrel and go .002 over and.or try quenching the boolits AFTER you powdercoat.

[Onebad06vtx]

I seat then taper crimp in another step.
never have a problem with leading.
And I am running them hotter then you.
Make sure the bullet passes the smash test.
If your seating and crimping in one step,that could be your problem
Or if there not passing the smash test,you need to figure out why.
either coat them better or check your oven temp.

[marlin39a]

I load that bullet in 10mm with longshot powder. I went to a Lyman M die to eliminate leading.

[blueline541]

I've pulled a random sampling while dealing with this and the coating is not getting scraped off while being seated.

My bullets pass the smash test.

I load my ammo on a Dillon 550 and seat and crimp in separate stations.

I bought the coated Bayou Bullets just to see how they would perform, and they lead noticeably worse than the ones I coat. Over the phone, he said he's never had the first complaint with his coated .40/10mm bullets.

My coating is not being compromised in the loading process and is passing the smash test. But homemade and Bayou Bullets are leading two Glock 20s and two Glock 29s. Maybe I should try an expander die from Double Alpha?

[sparkyv]

Stock or aftermarket barrels?

coating is not being compromised in the loading process and is passing the smash test. But homemade and Bayou Bullets are leading two Glock 20s and two Glock 29s. Maybe I should try an expander die from Double Alpha?

[blueline541]

All four guns are stock.

[Onebad06vtx]

Sounds like maybe your bullets are sized the wrong size.

[blueline541]

Sounds like maybe your bullets are sized the wrong size.

That could be, but that would mean Bayou Bullets would be as well. More so, give how badly they leaded. I think I'll order an expander from Double Alpha.

[farmbif]

it could be the Glock barrel, I shoot full power cast loads in Glock 9mm and 40 but use storm lake barrels, never any problem with leading

[Conditor22]

sometimes you find a larger barrel or a gun that prefers fatter boolits.

go as fat at will cycle and chamber with COWW/PC'd/water quenched and see what you get.

measure the boolits you got from Bayou Bullets. sometimes they/people make a mistake and send the wrong size.

[JM7.7x58]

I have read that some barrels have throats that are so sharp and shallow that a reaming is very helpful when shooting cast of any kind, lubed or PC’d. I haven’t had this problem with the Lee 401-175-TC in my .40 s&w.

I’ve had other problems though. Chambering and cycling where my problem.

I solved my problems with PC, sizing smaller, and a heavier charge of powder.

JM

[garandsrus]

Mine are sized to .401", but I didn't size the Bayou Bullets. I flare my brass enough to keep from sheering off the powder coat finish. I also measured a pulled loaded round to check for swaging. The pre-loaded bullet measured .400 the same as the pulled bullet
Thoughts or suggestions?

If your pre loaded and pulled bullets are .400, you are not sizing to .401! Open up your sizing die so that you get to .401. It will probably fix your leading problem. Some people suggest .402 in a Glock but I have no idea if they will chamber in all glocks at .402.

[GregLaROCHE]

There are a lot of good suggestions here. Also, try shooting a few without crimping, to see if you’re getting a bit of a roll crimp, that could be scraping off some PC.

[Onebad06vtx]

First thing you should do is slug your barrel.

[nicholst55]

I have read that some barrels have throats that are so sharp and shallow that a reaming is very helpful when shooting cast of any kind, lubed or PC’d. I haven’t had this problem with the Lee 401-175-TC in my .40 s&w.

I’ve had other problems though. Chambering and cycling where my problem.

I solved my problems with PC, sizing smaller, and a heavier charge of powder.

JM

This is a distinct possibility, and more common than many people realize. I'd suggest shooting a PM to member DougGuy and discuss this possibility with him. He can fix it if it is the problem. Check for other potential problems first, like an oversize bore or an undersize bullet.

[Taterhead]

I shoot a lot of 10mm coated bullets in my G20 and G23 with zero leading. 3% Sb, 1%Sn.

I size to .401, but after resting a few days the size relaxes to a touch more.

If a pulled bullet measures .400", that is too small for Glocks.

My standard expander was likewise too small in the shank, so the necks swaged the diameter down to .400". That was cured ny usong a larger RCBS 401 Cowboy expander. Swaging problem is gone.

You don't have that option on a 550. The DAA retrofit might have a shank diameter no larger than the Dillon, so it might not be the cure.

You might consider heat treating after coating and sizing to at least .401". Harder alloy will resist swaging.

[fredj338]

I run my own coated, HT or PC, in my stock G20, no issues, very good accuracy. I am betting under sized as well Glock bbls are slightly over size anyway, so with lead or coated lead, bigger is better. I would give 0.402" a try.

[blueline541]

I run my own coated, HT or PC, in my stock G20, no issues, very good accuracy. I am betting under sized as well Glock bbls are slightly over size anyway, so with lead or coated lead, bigger is better. I would give 0.402" a try.

You nailed it, as did others, and I genuinely appreciate the responses.

I ordered a Double Alpha expander funnel for my 550 and had Castboolit's lathesmith make me a .402 sizing die for my Star. Now I'm successfully shooting PC cast through my stock Glock 20 and 29.

Thanks again, gentlemen.