9mm leading, next steps?

[rbstern]

The pistol in question is a full size EAA Witness 9mm. Bore slugs out at .355.

I've been searching for an inexpensive plinking load for this gun, but I'm getting moderately heavy leading with my cast boolits, and I am not quite sure what to do next.

Yesterday's test load was: Lee 356-124TC, wheel weights, water quenched, sized .356, tumble lubed. I was careful in the final lube to make sure I had a good varnish coat on the boolits. Loaded over 3.9 grains of Red Dot, a mild load producing about 1050fps.

Shot 30 rounds like this. Function and accuracy were excellent, and powder fouling was minimal. However, the barrel was heavily leaded and needed a good cleaning after the shooting session.

Am I dealing with a rough barrel? I'm not sure where to go from here.

[StarMetal]

One thing to throw at you, you know when you water quench those bullets, or even heat treat them in an oven, that it takes a week or more for them to cure and start to become harder. So if you cast them and shoot them within a day or so, they are still soft. Anyways I don't think that is what is the matter. From what you are saying it really shouldn't be leading the bore. You miked it at .355 and sized to .356 which definately isn't under the bore size, the load isn't hot, maybe your bore is rough. How's it look visually? Is the gun brand new? If so I think I'd run a few hundred rounds of jacketed through it first to help smooth up those rough spots, then clean it of jacket fouling real good and try lead again.

Joe

[9.3X62AL]

Dittoes to all that Starmetal posted--and one further check......what is the throat's dimensions?

For practical purposes, the 9mm is much more a rifle round (pressure, fast twist rate, and variance of internal bore/throat dimensions) than a pistol round, when viewed in the context of its cast boolit utility. If the throat is larger than groove diameter, try your boolits at throat diameter or perhaps .0005"-.001" larger.

I haven't tried tumble lubing--at all. No idea how to guide you on that phase of the operation. I have had my best luck in 9mm with fairly hard boolits combined with softer lubes applied through a Lyman 450 sizer. Throats in both of my SIG-Sauers run .3565", so they get .357" boolits. Remington cases are used due to having the thinnest case necks I've found so far, and this combo enables the .002" diameteric clearance upon firing to ensure safe boolit release. Again, we're talking rifle internal ballistic dynamics in a pistol caliber.

Short answer--treat it like a 30-06....or maybe a 6.5 x 55......and it might start acting in a more civilized fashion.

[rbstern]

Guys, thanks for the helpful comments.

I think, just to cut down on the variables, I will make up a batch of test rounds using commercially cast bullets. If those don't lead, then I know I've got an alloy and/or lube problem. If they do lead, then it's a problem with the bore. Should simplify the troubleshooting.

I'll report back with an update. Thanks again.

[garandsrus]

rbstern,

If you need some comercially cast 9mm bullets, I have a bunch and can send you a couple handfulls. I have round nose and truncated cone. Both are 115-122 gr.

John

[rbstern]

John, thanks. I've got some 100 grain hard cast that I use in 380. Should work for this test.

I do appreciate the kind offer!

Rich