Lee Factory Crimp Die and leading

[rbstern]

The load in question is a Lee 358105 SWC, air cooled wheel weights, tumble lubed, pushed by 3.5 grains of Clays and a Rem 1 1/2 primer. This is one of my favorite plinking loads, very accurate out of revolver or levergun. But in my S&W 66 revolver, I get moderate leading from this round. My Rossi M92 levergun doesn't lead with these. Tinkered with a bit more tumble lube and that helped, but still leading in the revolver that needed attention after each session.

A friend sometimes shoots my rounds in his Colt Diamondback, which seems to have very tight chambers, so I decided to do him a favor and add a Lee FCD to my Loadmaster.

I just tested my first batch made with the Lee FCD. Exactly the same load as above. And the leading was non-existent. A dramatically cleaner barrel than I am used to seeing after 50 rounds.

Is it possible that a firmer crimp is changing the dynamics of the bullet obturation enough to make this possible?

I'm a bit mystified.

[Bret4207]

I'd be more inclined to think you're getting much better and more consistant ignition. I'll also wager you're getting a different amount of obturation than before, although whether you're getting "more" or "less" is another question. It's also possible the FCD isn't mangling the boolit as much as the taper or roll crimp you used previously.

[Dale53]

rbstern;
I have not yet used the Lee Factory Crimp Die. However, I have one ordered for the .32 magnum. If it works, then I'll get another one for .357/.38 special and also one for the .45 acp. I think that the concept borders on "Brilliant" and am VERY interested to see if it works for me. I certainly wish I had one back in the "eighties" when I was shooting IPSC. Over a five year period I averaged 15,000 rounds a year (all cast bullets by me and all reloaded by me). It would have saved a TON of time not to have to "gauge" each reload used in a match.

Thanks for sharing with us.

Dale53

[BCB]

rbstern,

I think the Lee FCD also sized the case when it is removed from the crimping die...at least it does with straight-walled cases so they will chamber in any revolver of that cartridge. MAYBE, by sizing the case as it is removed from the crimping die, it is sizing the cast bullet down a bit and allowing for a better fit in the bore??? Who knows as long as it is helping...BCB

[rbstern]

Thanks, fellas. Bret, I hadn't thought of the bullet mangle. I did sometimes shave lead during seating. More data gathering needed. We shall see.