10mm leading problems

[Arrow]

I am shooting a glock 20 with a kkm barrel. I am casting mihec 403-200 bullets using the shallow hollow point pins and air cooled wheel weights. My barrel slugs .401 and sizing bullets .402. Seating bullets 1.245" and using longshot powder. I tried 8.8, 9.0, and 9.2 grains. No signs of excess pressure. The accuracy was nothing special on any of the loads and all of them leaded the barrel. From the looks of it it looks like the barrel is clean for the first 1/2" of so after the throat and then lead for the rest of the barrel. Any ideas how to fix this? Anyone else using this bullet and longshot and can suggest a load?

[Sig]

Sounds like you got the size right. Maybe try a different lube or powder.

[ffries61]

Sounds like lube failure to me.

Fred

[RobS]

Well with Longshot you might be running pretty warm of a load. Online Load Data at www.hodgdon.com shows a 200 grain jacketed bullet with Longshot powder having a minimum charge of 7.0 and a max charge at 8.2 grain with a OAL of 1.260". I understand you are using it with the HP pins but the boolit itself didn't change in over all length so you are seating it deep in the case for a 180-185 grain or so boolit (less case volumn). Looks like you may be skidding the lands, exceeding pressures, as the bullet speeds up and increases RPM's causing gas blow by. Do you have a chronograph? If so what velocity are these running? Lube could be at fault too but the load could just be a bit warm for a plain base air cooled WW boolit. Try backing down the powder charge. Also have you pulled a bullet from a loaded round? I ask because sometimes a good lube will mask a slightly undersized bullet for the first part of the barrel but gas cutting will burn up the lube and then the rest of the barrel is left without the film gasket the lube provides.

[Love Life]

What are you using for lube? That sounds like a lube failure to me. Also, ensure the barrel is throated right. You aren't getting a shaved lead ring are you?

[RobS]

Also, ensure the barrel is throated right. You aren't getting a shaved lead ring are you?

Shaved lead due to a sharp or abrupt throat would likely cause leading at the start of the barrel from the pieces of lead smearing itself into the barrel.

[Love Life]

Shaved lead due to a sharp or abrupt throat would likely cause leading at the start of the barrel from the pieces of lead smearing itself into the barrel.

Would likely, but not always. My pistol is an example of that.

[Arrow]

I am using the Lyman moly lube that came with my lubrisizer. I have white label carnauba red and bac that I plan to use once my lubrisizer runs dry. Is this Lyman not a great lube to use with this 10mm? Could the red and bac fix this problem?

[Love Life]

Give it a try and report back.

[Sig]

I would hand lube a few rather than cleaning out the lubesizer.

[RobS]

I am using the Lyman moly lube that came with my lubrisizer. I have white label carnauba red and bac that I plan to use once my lubrisizer runs dry. Is this Lyman not a great lube to use with this 10mm? Could the red and bac fix this problem?


No Lyman Moly is a good lube.

[RobS]

I would hand lube a few rather than cleaning out the lubesizer.

Good option to see if lube makes a difference........but I don't think there will be a change.

[Sig]

Good option to see if lube makes a difference........but I don't think there will be a change.
That's what I was thinking too. Hence my reason for not cleaning out the sizer.

[leeggen]

ffries what are you using to measure the diameter of the barrel slug and the boolit? Should use a micrometer and not verneers. Sometimes the verneer will not measure real accurate. Which in turn could mean your boolit is not sized right. Just a thought and one thing to think about.
CD

[harley45]

i had to goto PB gas checks to solve my 10mm leading problem, it was the only way I could get expansion and no leading. Try Sage's outdoors

[Arrow]

Any other ideas guys? Thanks for the help so far.