40 S&W Leading.

[fusionstar916]

Im having bad leading inside my M&P40 stock barrel. It was pretty rough looking from factory with an off center crown.. but it shot well so I kept it.
Slugged the bore, but I have odd number of grooves which mean my mic is on a land and a grove at all times, the largest spot is .4002 My bullets are sized to .4011, and egged .4008 to .4011
Water dropped wheel weights and scuba weights. Cant dent with my nails.

Anyway, Im shooting LEE's six pack 175 grain Truncated cones tumble lubed with white lable xlox. Perhaps I am not using enough or getting enough in the lube grove. Your thoughts?

[fredj338]

The 9mm & 40 are tough to get right. What powder, what vel/pressure level? Try ACWW instead. Sometimes harder isn't better w/ low rpessure loads. I have never had great results w/ Alox & tumble lube. I also hear many guys complaining about leading & TL bullets.

[Edubya]

Disassemble one of your boolits and remeasure to make sure that you're not over crimping and smashing the boolit. If you are using a fast powder it is burning before the boolit is engraved and this will lead to gas burning the un-obturated lead.

EW

[geargnasher]

Edubya knows. Battled one of those M&Ps myself, among others in .40. Chamber had a sharp edge that shaved lead, and boolits came out of the brass smaller than groove due to case swage and the cursed Lee pistol FCD. Gas leaks cause leading by abrading dust and laying it down in the bore to be ironed on by the passage of the boolit. Sticky alox residue can make it worse. Shavings get ironed on too, in thick lumps. Gas cutting from loss of obturation (seal) sprays the bore with fine lead mist and it ends up in long, thin streaks that can accumulate rapidly into thick deposits.

A lot of your success or failure with the .40 will lie with the alloy choice, powder choice, and the dimensions of the expander spud you use. Throats smaller than the boolit with a 90-degree sharp edge at the end of the chamber (or in some cases at the end of the throat where the reamer stops) are mechanical malfunctions that need to be corrected for best results with cast.

Leave some bellmouth, as much as will allow the cartridge to fully chamber when you drop it in there under it's own weight.

Oh, and if you get leading, unless you're using liquid Alox, 95% of the time it has nothing to do with lube failure, it has to do with FIT failure somewhere. This ain't copper-condom shooting, whole different concept to get it to work. If you ARE using liquid Alox, fit and load/alloy balance becomes even more critical to getting things to work correctly.

Gear

[fusionstar916]

4.6 gr universal clays, also have some winchester 231 I could try.
No crimping, just removal of the flare.
Not using Lee fcd, just the seating die.
Water dropped WW's, will anneal some bullets and try again.
I'll try reducing the crimp to leave a little flare.
Also will try some 50/50 soy wax/vasaline pan lubed bullets. Had great success with paraffin/vasaline in a friends load. I have 25lbs of soy wax from candling making.
If that fails, I'll just powder coat the suckers.
Thanks guys.

[runfiverun]

the whole 401 in a 402 thing ain't gonna work,especially with a rough barell.
i don't care if you pack the barell full of lube before each shot you are gonna have leading.

[popper]

PC solved all my problems with 40. 1 user just used thinned lanolin then dipped in the PC with tweezers.

[fusionstar916]

PC solved all my problems with 40. 1 user just used thinned lanolin then dipped in the PC with tweezers.

PC? Sorry only started casting a month ago.
Powder coating? I assume? The dipping in lanolin threw me off.
So I wet the boolits in the thinned lanolin, dip it into powder coat paint and cure it? I have a powder coating gun on the way.

Pulled some boolits and they stayed the same diameter. So they are coming out like they should.

[Hounddog]

Have you tried just loading tumble lubed boolits without sizing. Sounds like a fit issue to me. I would try casting some fresh ones and air cooling them, then just tumble lube them and load and go. I shoot cast in my M&P 40 all the time and use both lee 180 tc and the 180 swc tumble lube boolits. I get better accuracy with both boolits using slower powders like power pistol, aa#7, blue dot, longshot, 800x, etc...

Hope this helps.

Hounddog

[popper]

Yes,just dip. Check the PC thread.