What is this caused by?

[milprileb]

Okay, I finally got a load that shoots accurately in my 9mm using Lee 120 gr TC bullets, 8 parts WW to 2 parts lead, 2% tin, BAC lube.

But I get leading right at the throat of the barrel. Not anywhere else. The first 1/8 of rifling now accumulates leading.

Now if I take these BAC lubed bullets, tumble lube them and use them 2x lubed, I don't get this issue.

Here is what I think,pls correct me :

a. Not enough of a lube groove on Lee TC bullet so not enough BAC is there to prevent leading.

b.Unique powder is too high a burning rate and causing the bullets to jump too fast into rifling and leading.

C. All of the above (which is what I suspect)

Thanks for your help

[WHITETAIL]

IMOP,I would say you have not enough lube in the groove.
Here I go again, try lubing them with JPW first.
When dry ( let dry over night) then size and lube
as you normaly do.:cbpour:

[milprileb]

White Tail: They are lubed in a SAECO machine with BAC then follow on lubed iwth Lee Liquid Allox lube: that way they don't lead. Just use BAC and they lead.

I don't think BAC is failing me here , do you ?

[gray wolf]

I think your bullets are to small, leading in the throat is a good indication
You bullets need to be a little bigger ---say .001

[MBTcustom]

Pull a boolit and check size. Leading is caused by undersized boolits, not skidding. 9mm dies are famous for making the case necks undersized and squishing the boolits down to a smaller diameter.

[milprileb]

I am using a .358 M Die.
Pulled bullets measure .358
Bore is .3575

Do I need .359? size die for lubrisizer and a M Die at .359 ?

[btroj]

I would try a larger bullet. I bet the extra lube is sealing the throat a bit while the bullet is entering the barrel.
I have had the exact same thing with CR in my 1911 in 45 ACP. I changed lube and no more lead.

If all else fails just keep double lubing them. A coat of LLA is pretty quick to apply.

[popper]

Shards or ring-around-the-toilet leading at chamber? ACWW/Pb or WD? Try w231 vs unique? I'm suspecting a hard alloy, slower powder and no lube on the CB when it starts, possibly a smidge too small. Try sparingly wiping the rear drive band with canola oil before seating and see if it doesn't go away.

[slinger35]

Is your barrel throated for cast boolits ?

[geargnasher]

Is your barrel throated for cast boolits ?

DING-DING-DING! We have a winner!

Gear

[milprileb]

This is my first ever exposure to this question: How do I know if the barrel is throated for cast bullets ?

To m y knowledge, I have never seen a pistol sold as such. Gear: is there a reamer I need to get and fix this barrel or what ?

To those who think .358 might be too small for my bore, can a .359 bullet actually fit in a 9mm case?

[geargnasher]

Many of the modern automatics I've fought with have a step in the throat of the barrel, between the end of the chamber and the origin of the rifling. Often this step is very sharp and there is no tapered transition from boolit size to groove size, and even the lands are often blunt and sharp, ending at the same step. This causes the boolits to be shaved rather than swaged as they go into the barrel, and the shaved lead smears and causes crusty buildup within usually only the first inch of the barrel.

There are "throating" reamers available to fix this in .45 ACP I know for sure, and probably in the other calibers as well. I've fixed several with a lead lap mounted on a brass rod and valve grinding compound.

Gear

[geargnasher]

You're in luck! I just happened to look at the 9mm thread next to this one and another member posted that Brownell's does indeed sell these throating reamers to fix the shaving with cast boolits. http://castboolits.gunloads.com/showthread.php?t=158677

Gear

[geargnasher]

Is your barrel throated for cast boolits ?

Yeah, YOU!, Thanks, didn't notice it was you that posted the thread 'til just now.

Gear

[milprileb]

Thank you Gear and slinger 35: it can help, can not hurt and frankly, its something I never thought existed. I am calling Brownells Monday for certain.

[slinger35]

Thanks for the positive comments fella's

[milprileb]

You got the Gear "DING DING DING" ring of approval.

I don't ever remember seeing that happen.

Best to buy a Lotto ticket pronto !

[MBTcustom]

You can also rent the throating reamer as you will probably only use it once.
This is my vavorite place for such a situation:
http://www.reamerrentals.com/searchresults.asp?cat=25
For $15 you can't go wrong.
Now, once you get the reamer, be very careful because a throating reamer takes off just a few thousandths of an inch when creating or deepening a throat. You want to drive it with a T handle and be very careful, as one slip and you can go too deep and be SOL (ask me how I know). Buy some cerosafe so that you can do a little, and see how you did, and if it needs a little more etc.
Also, see if you can use a pin gauge set to measure what size pilot you need for your barrel. You could just drive on ahead and let the rough edge drag, but the right way to do it is to get the appropriately sized pilot so that you are certain that your throat is concentric with the bore.
Good luck!

[popper]

milprileb - reaming may eliminate the sharp edge that cuts Pb off an oversized CB. It won't solve the problem of NO lube on the CB when it comes out of the case - LLA did solve that. I'm using almost pure in 40SW, case sizes small and if I don't lube the drive bands I get leading at chamber. I use a soft lube. Hard lube doesn't do anything until spin or pressure or heat gets it onto the bbl. You don't have the freebore and forcing cone of a revolver.

[milprileb]

Very Interesting Maybe I ouht to try 50 50 NRA lube formula
instead of BAC lube on 9mm bullets.

ITs no bother to LLA tumble lube my bullets after I lube size them in Saeco machine with Bac or any stick lube.

[popper]

If I don't use enough, I get the dirty ring on the muzzle end. When firing as cast(pure0 and unsized cases, I sometimes get a few Pb rings (shaved Pb), but the go away with the next shot. When I get it all correct, clean as can be. I suggest the cooking oil as it bonds to metal, is cheap and doesn't add any thickness and can be wiped on with the finger - doesn't take but just a smidge. It's an alternative to one of the oils in Felix.

[1Shirt]

This forum can sure solve a lot of problems for folks if they will read and heed!
1Shirt!:coffee:

[MtGun44]

I apologize for my ignorance, but what exactly is "BAC" lube?

Bill

[just.don]

Blood Alcohol Content?????

[H.Callahan]

BAC lube sold by White Label Lubes

http://www.lsstuff.com/lsstuff-stuff

It is the first lube in the right column.

...and it is good excrement, too.

[MtGun44]

Ok, now that I know what it is, I would suggest a test with straight NRA 50-50 or
LBT soft blue and see if this fixes it.

Bill

[milprileb]

MTGun44, I assume you think BAC might not be soft enough on 9mm bullets and that contributes to leading in the first part of the barrel ? ITs worth a try on NRA 50 50 and Soft LBT Blue.

[geargnasher]

If you're getting leading with what you're doing and you're using BAC, it ain't the lube that's the problem.

Gear