bullet mold question

woodsrunner

I recently bought a used bullet mold sight unseen. It's a lyman #358156 gas check. The mold is in great shape except one side has a big rust pit right where the gas check shank should be formed. One side of the mold almost looks like a plain base mold. Otherwise this mold is perfect. I'm wondering if I should cast some bullets and try shooting them, or removing the ridge that forms the gas check shank from the mold. I went poking in the tool crib at work tonight and found an end mill that mic's up at .356, I have access to the tool rooms Bridgeport. It would probably take me longer to set it up than to do. Anyone have any thoughts on this? I'd be interested in hearing them.

Woods

How big a boy are ya?

woodsrunner

If I wanted to cast some bullets for 9x19mm and .38 special, could I use the same bullet mold, since the mold for 9mm is .356 in diameter, or would I have to buy a different one for each?

Jody Commander

Due to extreme poverty, I cast and shoot lots of cast bullets, love them. I do not care for gas checking, too much trouble for just a hundred or so extra feet per second, go ahead and remove the gas check ledge, just be sure to get it all as with cast bullets You are better off with a base Dia. larger than the rest of the bullet. it uniforms the base when sized I have bought nice molds for low price bexause the owners did not like to place gas checks on the bullets, I take a Dremel tool and grind the ledge out, polish the area where the ledge was and sand any burrs off the top of the mold so they do not interfere with the sprue cutter. shoot great! and I save money, America,what A country,

Iconoclast

Woods, when I was young & foolish, I used gas check designs in handguns. It took a while (longer than I care to admit) to realize that at the velocities typical in any standard caliber, this was merely an extra step and an extra cost. I don't use those designs now - or generally not. But if I were going to remove the GC lip on a cavity, I'd definitely go with the milling machine approach over the Dremel, to minimize any possible inconsistencies in that key base area. The one true advantage of the gas check in a normal handgun is the uniform base / bore seal afforded by its use.

Which brings me back to your first option - take a look at how the bullets look after casting a few. If the rust pit leaves a significant lump where the GC should go, the check isn't likely to fit properly and at the very least every bullet you cast will have a little extra tendency to inaccuracy built into it, so I'd think in terms of the lip removal. Just about the worst place for a large rust pit, IMO . . . figures, right?!

If that's the route you follow, I'd take a look at the mold after using the .356" mill. If the lip has not been totally removed, I think I'd try to find something a little larger. Uniformity isn't as important with the typical use of a cast bullet as a practice load, but even so, if one is going to invest the time & effort to cast / size, it makes sense to have the right dimension tools. I've never had the tooling to measure the interior of the cavities w/ reliable accuracy, but among the various PB & GC designs I've used, the dropped 'as-cast' slugs measure .359 to .362" depending on many variables, which I've always sized .358 to shoot in various .357 M / .38 spl handguns. If the diameter, especially at the base, isn't uniform and at least .358 (i.e., not completely filled out such that one can see the smooth finish left by the sizing die with a nice square bottom edge), I put it right back into the pot; usually one can determine this before bothering w/ the sizing, when culling all obvious defects after casting. The consensus of writers is that the base is the most important part of the bullet and nothing in my experience contradicts that view.

Would be interested in how you do in this project. Good luck.

v35

It may be easier to bore the gas check diameter accurately using a four jaw chuck in a lathe than trying to find the center of the cavity using a Bridgeport.