severe leading .40 s&w

[twally]

I have shot commercial lead and my own cast straight w/w for several hundred rounds without any problems.

Now, all the sudden i'm getting a lot of leading, like the groves are full at the muzzle.

I haven't changed the alloy at all just straight w/w, tumble lubed with LLA 45-45-10.

my load is 3.7 gr. clays 182gr. tc boolit from a lee175 gr. mold.

although the bullets sat in a plastic mayo jar for several months lubed before loading this batch, i don't think that should be a problem.

any wisdom to help solv this problem??

[jameslovesjammie]

Slug your bore and measure the slug. Slug a boolit and make sure it is at least .001" larger than your bore slug.

I never had a leaded barrel until I got a .40. After slugging my barrel, it was .400. My .401 Star sizing die was taking it down to .399" and I had some of the worst leading I have ever seen.

[BulletFactory]

Have you measured a pulled bullet for diameter?

[Rattlesnake Charlie]

You have used the same bullets before?
If so, are they sized as before?
If so, are these from a different batch or casting session?

[Calamity Jake]

Sounds like you are running out of lube, does the mayo jar boolits have the same amount
of LLA as previous batches?
Try applying another coat of LLA to see if that stops the leading. Don't change anything else but the amount of lube.

[Doby45]

Lube is running out.

[popper]

#3,#4,#5 ++. Same load for sure? Lubing with 'just a squirt' and 'a bunch of bullets' will get uneven lubing. Lube from the same batch? I assume the barrel was clean before you noticed this problem, no lube or lead buildup

[462]

Not enough lube, or insufficient lube for the load.

[CWME]

I agree with the lube and would start there if I were in your situation. You may be running into a hardness issue as well. The WW age harden over some time. If the others were fired shortly after casting and sizing then they should be softer. Just a thought and YMMV.