rcbs 9mm mold/leading badly

[rp85]

hello;

got a rcbs 9mm mold (09-115) for a 115 grain bullet at an estate sale. also got a large number of this bullet already cast, but not sized or lubed. bullet is weight 120 grains, dia. of .357".

used lla/jpw for several coats of tumble lube. with 3.2 grains of bullseye the barrel was completely leaded after 30 rounds. don't think speed or bullet dia. was the leading cause. have no idea on bullet metal.

have learned any bullet speed above 950fps in the 9mm i have, the barrels will have leading.

any suggestion on leading case????

thanks for any input.

rp

[Bullet Caster]

You should slug your bore and find out what dia. it is. Then you can fit the boollit to the bore with the proper sizing die. Do you have a micormeter or a caliper? You should start with pulling a loaded round and see what size the boolit base is. Seating the boolit could be shaving a little lead off of the boolit and this will cause the boolit to be significantly smaller thus leading the bore. Just my 2 cents. BC

[captaint]

Let's see, rp85, if this happened to me, and it has, I would look at these things. First, is the barrel of your pistola really, really clean and copper free?? Next I would look at boolit diameter and/or alloy. Apparently we don't know what the specific alloy is, since you didn't cast the boolits yourself. Lastly is lube. I'm not a big fan of tumble lubing. Tried it for a while for my 45, and it did work ok for that. Just didn't enjoy the process. I had to make my RCBS 124 gr boolits bigger, so I could size them at .3575. I was using LBT Blue soft, so that wasn't the issue.

So, after going to straight WW alloy, and bigger boolits, my leading went away. It wasn't real bad, like the whole length of the barrel, but there was enough that it was annoying to clean it out. Just keep it simple and try those things first and let us know how it works out.. enjoy Mike

[9.3X62AL]

SIZE MATTERS. And any part of the reloading sequence that alters boolit size downward can set up the scenario for leading. I don't use LLA, and can't help much with that part of the question.

Once you have micrometer in hand......check the diameter of the die set's expander spud. Many are as small as .351"-.352". A spud this small is well-nigh GUARANTEED to set up boolit diameter reduction during boolit seating. A larger spud is indicated for .357" boolits--.354"-.355".

Another great way to reduce boolit diameter is with injudicious over-application of taper-crimp. All that is needed is to straighten the flare out, and a well-adjusted roll crimp seater die does that easily. Taper crimp dies have no place in the cast boolit reloading sequence, in my view. I wish like aitch-ee-dubble-ell I could find a 40 S&W/10mm roll crimp die, to go with my much-aged 9mm and 45 ACP R/C seaters.

While on the subject of those infernal taper crimp seater dies......DO NOT seat boolits and set the taper crimp during the same die step. Seat boolits in one step, THEN re-run the seated assemblies into the die to straighten out the case mouth flare. In this way, a taper crimp seater die can become almost useful, and not ruin boolit sidewalls.

All of these process alterations are specific to cast boolit autopistol reloading. Most current die sets "assume" the use of jacketed bullets, and are dimensioned accordingly. Castings are far more delicate than are the "j-words", and can be ruined if care isn't taken in their handling in reloading dies.

[rp85]

thanks for replys.

barrel is free of any copper. barrels have been slugged and they are .356".

the leading i'm have with the rcbs mold covers the entire length of the barrel.

have other 9mm molds and these bullets are sized to .357" without any issues. have shot the other cast bullets through a chronograph and i know 950fps or faster = leading in my 9mm (s&w, ruger, browning, sig).

the load i'm using, 3.2 grains of bullseye, is giving me FTF. to light to op the slide.

could my lla/jpw be to thin???? also if the mold was designed for a 115 grain bullet, but i'm getting a 120 grain bullet, then the unknown alloy might be on the heavy side?.?.

thanks for input.

rp

[Tomuchiron]

Just went thru the exact same thing. Your putting .357 bullets in .356 cases. the other replys were all right on que. Pull some of your bullets and see what they now measure. A possible quick check is ,does your cases have a nice smooth sides or are they bulge from the larger bullet. Mine are now bulged and more aaccurate.
If you only shoot 1, 9mm gun.,, A possible solution and test is to get a universal decapping die and use it instead of the first resizing decapping die. these cases are sized to your chamber and the .357 will be loaded into a larger than normal 9mm case. .. Now just prime,bell,powder and seat , crimp slightly. and test in your barrel. If you own multiple 9mm guns. you will have to test all the barrels and find the tightest chamber as your go-no-go gauge.

I am sure your pulled bullets will be smaller than .357 ,, Let us know what they measure.
With the 9 being a tapered case. Will the bullet be tapered?

Mike

[Bullet Caster]

I would think that 3.2 grains of BE is a little light for 9mm. I use the 124 grain TL Lee mould for my 9mm with 4 grains of BE. I crimp that boolit just behind the front driving band. They drop anywhere from 121 grains to 125 grains. Since they drop at .356 I don't size them. Just lube 'em and shoot 'em.

Search the threads for 9mm leading. There's a bunch of info already stated about the 9mm. One thing is to remove the expander in the powder thru/expander die and replace with one from a .38 spl. die (a spacer is required) to make the expander go deeper into the case. That will yield enough space to accept the larger .357 boolit.

The first thing I did after sluggin' the bore was to make up a couple of test rounds (no primer & no powder) and do everything from sizing to seating as you normally would. Then pull a seated round and measure. Somehow in 9mm the case can down size a boolit. At least that's what I have found. BC

[Wal']

I solved a lot of my 9mm leading problems by using a slower burning powder, slows up the acceleration of the boolit down the barrel.

Hodgons Universal would be my recommendation to start working up a load.

[9.3X62AL]

I size/lube my boolits with a Lyman 450 size die @ .357", and lube with Javelina alox/beeswax. Lube groove is filled. Alloy is 92/6/2. At .357", I have no leading in 2 SIG-Sauers (226 and 228) or a Ruger P-89X. There was none in a now-departed Browning Hi-Power or S&W M-459.

I don't use Bullseye in 9mm applications. I use WW-231 as my fastest powder, and more often use Unique--Herco--or Blue Dot. With those last 2 fuels, I get 1250 FPS with the 125 grain boolits with no leading and accuracy that beats jacketed bullet work.

The real "secret" to 9mm, 40 S&W, and 10mm cast boolit reloading is to treat these pistol calibers as if they are chambered in rifles--because in many respects (high pressures--fast twists--high velocities) that's exactly what they are.

Harder alloys--softer lubes--slower powders. Sounds like lyrics for a Tom T. Hall song.

[MtGun44]

And a real lube.

Bill