9mm Leading Issue - Help!

Boolit Bub Join DateMar 2011Posts30

Ok, I have been reading post after post trying to get ideas of what I could try next to solve the leading issue that I have been experiencing. I could really use some help solving this as I have been struggling for some time with this.

Details on my setup and materials:
-First off, I am shooting a Sig Sauer P226 Stainless Elite which has a Stainless Bar-Sto 9mm conversion barrel custom fitted.
-I slugged the bore and used a micrometer to measure it. It came out to a very consistent .357. I measured multiple times with the Mic and calipers just to make sure I hadn't misread this somehow. I am very sure this is correct.
-I am casting using straight WW alloy in the Lee 356-120-TC 6 cavity mold which seems to drop about .358-.359
-I bought a .358 sizing die for my Lyman 4500 Lubrisizer and have been sizing to this, based on the slugging result.
-I am using the Jake's Moly Ceresin lube since it seems to have a good reputation.
-I am using 3.8gr Titegroup powder which is not super fast, but not super slow. It will lock the slide back on the last round about 75% of the time.

Using the above, I tried shooting 50 rounds with air cooled WW alloy and I get leading. I tried water quenched WW alloy and I still get leading. I think the sizing die is right, I think the lube should be more than adequate. I think that the powder charge is pretty middle of the road and not in the extreme one way or the other.

One more clue - the leading seems to start about in the middle of the barrel and continue through to the end. I don't seem to get leading near throat or near the beginning of the barrel.

Today after work I went and shot 50 of the water quenched bullets thinking it was going to solve the issue. I was really confused and disappointed when it didn't. What do you guys suggest? Should I go to .359? Anything else I am not thinking about?

Here are some pics of my bore.

If they'll chamber properly, try a few of the unsized .359" boolits. .002" over bore diameter may be all you need. Then there's the usual leading-issues problem solving: different lube, in your case the factory barrel, different alloy and etc. Just be sure to change only one variable at a time or you'll likely have no clue which action fixed your problem.

"Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime.", old Chinese proverb.

I also had issues with several 9MM's for quite awhile. I tried everything from harder alloy to softer alloy, sized from .356 to .359,at least 6 different powders from fast to slow ( working up ladder loads on each one ) 5 different boolit styles, to no avail. It got decent toward the end where I only got very slight leading but was still not happy with the results. I finally tried in desperation PB gaschecks from Pat Marlin and never saw leading after that. Cheating a little but it fixed my leading issues and I never looked back.

Since your leading begins midway down the bore and continues to the muzzle, two things come to mind:

1. Lube failure. Try some others.
2. Barrel constriction. Not likely, but possible and easy to check for. Slug part way from each end and see if the groove diameter at the muzzle is the same as just forward of the throat. You might also be able to detect one by slugging end to end, then lubing the bore and running the slug back down the bore in the same orientation, fitting the engraved slug to the same lands. Push it from the muzzle with a rod and see if the resistance is the same down the whole length of the bore.

Also, have you pulled some boolits from assembled ammo and miked them to make sure your brass is not swaging the boolits down? I'd expect leading to start closer to the throat if that were the case, but it's something to check out when setting up for 9mm anyways.

Boolit Bub Join DateSep 2012Posts31

Titegroup is my go to powder. It does seem to burn a littlewarm and some of your problem might be there. Hp38 seems to do better but with 40+ pounds of titegroup i am continuing to use it. My glock barrel and aftermarket wolf barrel both micout at .355. I size .357 which really helps in the glock factory barrel. I load 3.6 titegroup with the lee tc and load a short OAL never had a problem with slide lock.
Actually with the tc the begining of the cone is right at the case mouth.

Another thing that has helped me was changing my lube recipe I "diluted" the mix with a little more vaseline and added some carnuba wax from car wax. A softer lube seems to work better for me than a harder lube, in your case you are getting leading in the last half of the barrel.

This suggests that you are running out of lube. I like a softer lube that flows more easily. With a real long 9mm barrel it is wholly innapropriate but in my glock 34 with thraded barrel 6.02" (or thereabouts) it helped a great deal.

Your alloy may be a bit hard. I like( for low velocity plinking) 50/50 dead soft/COWW +2% tin for fill out - water quenched.

The last thing is your expanding die. This is a common problem, seat one of your bullets after your normal case flare then pull it. Measure it. Dont be suprised if you end up with a boolit thats.354-.355.
for the lee expander in 9mm you can use a 38 sw expander to keep from swaging the boolit in the case.

Thats the best I can do on no sleep.
Hope something there helps

98% probability you are swaging down that bullet when seating in the case.
You are not adequately expanding your cases. Depth and or diameter. Likely both.
Are you sorting cases by head stamp?

I also had issues with several 9MM's for quite awhile. I tried everything from harder alloy to softer alloy, sized from .356 to .359,at least 6 different powders from fast to slow ( working up ladder loads on each one ) 5 different boolit styles, to no avail. It got decent toward the end where I only got very slight leading but was still not happy with the results. I finally tried in desperation PB gaschecks from Pat Marlin and never saw leading after that. Cheating a little but it fixed my leading issues and I never looked back.I also used a lyman "M" die for expanding my cases with no reduction in dia after pulling seated boolit. Good Luck with your endeavor with the 9mm , I hope it goes better than mine did.

Boolit Master Join DateFeb 2009Posts877

The case could be sizing those boolits down, but WDed lead didn't work for you either. Did you give the WDed lead time to harden up before loading the boolits?

Otherwise, maybe try another lube and check for constrictions in the barrel (already mentioned). BTW, if the barrel has any moderate constriction, you will feel it when you drive the slug/boolit through.

Do you have another boolit you can try?

I like the idea of trying .359 boolit.

Boolit Bub Join DateMar 2011Posts30

Wow, this is a seriously cool group. I really appreciate all of the responses and you helped me identify the things that I have not tried yet. I will make every attempt to list out the things that I am hearing, try them, and then report back to this thread until the problem is solved.

The barrel I have is a conversion barrel to convert the .40 S&W Sig down to a 9mm with just a barrel change. This means that I don't have a 9mm factory barrel to compare this one against. The Bar-Sto barrels get good reviews and I don't expect that it would be a quality issue, but we'll see I suppose.

What I am going to try right away
-Try some .359 bullets - I will likely need to work on expanding the cavities to get them to drop larger
-Double check to make sure that my expander die is expanding adequately - Now that I think of this, I think that I am not expanding enough, I will fix this right away
-Pull a bullet out of a loaded case and Mic it. Share results
-Try some different lubes - I tried a softer beeswax lube with similar poor results, but I have some Lyman Moly that I can try
-Re-slug the barrel looking for barrel constrictions - the tension was fairly consistent when I did this, so I doubt I have an issue, but I will do this anyway to double check.

What I will do if the above does not yield results
-Try new powders to
-Try new lead alloys

Last resort
-If all else fails, use PB gas checks

I thought of a couple other things that I need to provide to this thread.
-OAL of bullet
-Pics of the bullets in question
-Details of cases fired from this gun

Boolit Master Join DateFeb 2009Posts877

Yes, make absolutely sure your boolits aren't being resized when being seated into the case. I would start with that one. I doubt you have a constriction in the barrel, but who knows...

looks like it's starting about where your pressure drops off.
mark the barrel where it starts.
bump the load, and see if it moves.

it's all an educated guess,,,, till the trigger is pulled.

the more i find out about shootin boolits, the more it contradicts everything i ever learned about shooting jaxketed.

Boolit Man Join DateJan 2009Posts83

New barrels, are new guns for that matter, some times need breaking in.

Shoot it with mild loads for 300 or 600 rounds, cleaning often. Pressures are higher in new barrels and drop down a bit as they smooth out.

Then see if you have a problem.

good luck

Add 2% tin to your COWWs and let the AC'd bullets age for 7 - 10 days before lubing, sizing or loading.

Change lubes. Try the Lyman Molly but a good soft lube like Lar's NRA 50/50 or BAC will do better.

.358 sizing is fine.

Bump the load to 4.2 gr TiteGroup or switch to 4 gr Bullseye.

I shoot and have shot the same 356-120-TC (and several other 9mm moulds of 115 - 125 gr) cast of COWWs + 2% tin, sized at .356 - .358, lubed with Javelina (NRA 50/50 lube) or BAC and loaded over 4 gr Bullseye in many 9mm handguns and a few subguns with excellent accuracy and no leading. Your leading is caused by a tin deficient ternary alloy, improper lube and too low a psi.

Larry Gibson

Boolit Master Join DateMay 2012LocationRepublic of Texas, District of Round Rock.Posts308

Sounds more like a lube issue. If your lube is running out halfway down the barrel, maybe it's your bullet selection. How big is the lube groove? Only 1 groove or two?
Have you TESTED the bullet hardness and compared it to the recommended pressure for that hardness?

Griz44Mag
Here in Texas, It's the Biggest, Best and Most Important (or we just won't talk about it)

You may not post new threadsYou may not post repliesYou may not post attachmentsYou may not edit your postsForum Rules

Abbreviations used in Reloading
Pointed Soft Point "Core Lokt"

View the original article here