S&W Model 15-2 with terrible leading

[tranders]

I have been loading MBC 148 grain double ended wadcutters with 3.7 grains of HP38 for my S&W Model 15. Loads seems to shoot ok,but get lots of leading. Ribbons of lead in the throats and forcing cone area.
After the first round of testing these loads, I sent the cylinder to DougGuy to uniform the cylinder throats and as usual he did a great job.
2nd round of testing and the same problems. Ribbons of lead in the throats and forcing cone. Might add the projectiles are measuring .358.
My guess is maybe projectiles are under sized??
I have since bought a Lee 158 grain flat nose mould and these are dropping at .360 with Lyman #2. Have yet to test these out,but hoping to alleviate the leading problem.

Any helpful ideas would greatly be appreciated.

Thanks!

[Petrol & Powder]

Others will probably have more experience but my first question is, "what type of lube are you using"?

My second thought is alloy way too hard followed by not enough pressure.

I had a S&W model 64 that wouldn't shoot worth beans until I got the load almost to max with HP-38 [ww231]. Once I got close to max with a 160ish grain bullet cast from 10-11 BHn alloy, it settled in nicely.

[JonB_in_Glencoe]

Generally 38 WC bullets are soft...what hardness are your MBC bullets?

If they are soft? one problem is the bullet being swaged smaller during seating, if you don't expand the case enough. Have you pulled a bullet from a loaded round, to see what size it is?
What dies are you using, most dies are designed for loading J-words. Most of us cast boolit shooters will modify a expander die, so it expands the case larger to negate that issue. Generally you want to expand the case so it's .001 or .002 smaller than what your bullet size is...and again, this is much more important when using soft bullets.

[tranders]

MBC uses a hard blue lube on all their lead boolits. The BHN is stated as 12 on box. I can't make a dent with thumb nail.

I am lubing with Alox for the boolits from the Lee mould.

[tranders]

Generally 38 WC bullets are soft...what hardness are your MBC bullets?

If they are soft? one problem is the bullet being swaged smaller during seating, if you don't expand the case enough. Have you pulled a bullet from a loaded round, to see what size it is?
What dies are you using, most dies are designed for loading J-words. Most of us cast boolit shooters will modify a expander die, so it expands the case larger to negate that issue. Generally you want to expand the case so it's .001 or .002 smaller than what your bullet size is...and again, this is much more important when using soft bullets.

No, I have not pulled a bullet, but I will this afternoon. I'm using RCBS dies.

[JonB_in_Glencoe]

standard RCBS dies?
or the RCBS 'cowboy' dies that are designed for cast bullet loading?

[tranders]

standard RCBS dies?
or the RCBS 'cowboy' dies that are designed for cast bullet loading?

Standard RCBS dies. Just pulled two boolits, both measure .3585. I am using Western nickel plated wadcutter brass.

[JonB_in_Glencoe]

well that sounds good, I can't imagine a S&W bore would be larger than .3585
How does the throat look?
also, maybe slug the barrel and feel closely for thread choke.

[376Steyr]

I suggest getting some soft, swaged commercial wadcutters and try them. My experience with commercial cast wadcutters is they tend to be way too hard to be used with normal "wadcutter load" charges of fast burning powder. I suspect your Lee 158 with Lyman #2 will give you trouble too, as #2 is a pretty hard alloy to be using at standard .38 Special pressures. When it comes to the .38 Special, harder is not always better.

[tranders]

well that sounds good, I can't imagine a S&W bore would be larger than .3585
How does the throat look?
also, maybe slug the barrel and feel closely for thread choke.

Slugging the barrel will be my next step. Thanks for your help.

[tranders]

I suggest getting some soft, swaged commercial wadcutters and try them. My experience with commercial cast wadcutters is they tend to be way too hard to be used with normal "wadcutter load" charges of fast burning powder. I suspect your Lee 158 with Lyman #2 will give you trouble too, as #2 is a pretty hard alloy to be using at standard .38 Special pressures. When it comes to the .38 Special, harder is not always better.

I am in agreement that maybe the lead is too hard as this point. Might try using these boolits in the 357 magnum and pushing them faster and see how they perform. Thanks for the help

[sixshot]

I would try a soft alloy & powder coat them. Might try some sized & some unsized.

Dick

[Larry Gibson]

MBC uses a hard blue lube on all their lead boolits.

That is the problem. Suggest you TL those WCs with a light coat of LLA as per Lee's instructions. No need to size again though, just lube and let dry thoroughly before loading. Also suggest you drop the charge of HP38 to 3 gr.

Larry Gibson

[tranders]

That is the problem. Suggest you TL those WCs with a light coat of LLA as per Lee's instructions. No need to size again though, just lube and let dry thoroughly before loading. Also suggest you drop the charge of HP38 to 3 gr.

Larry Gibson

Will give that a try.