Hollow Base Molds: Hollow Design Experimenting?

[.41LC]

I have a two cavity hollow base NEI mold for .41 Colt, overall the mold is decent but the hollow base plungers are rough and inconsistent. I will need new ones to use the mold. It's a long story but I'm not interested in sending the mold back to NEI and dealing with them any further. This would give me a chance to experiment with a different design.

Anyone played around with different shapes and lengths for the plunger in a hollow base mold? What were your results?

[GLL]

Drop Buckshot a PM and explain what you want ! I am sure he can help you out !

Jerry

[JudgeBAC]

Buckshot made a hollow base pin for a .41 WC mold I have. He did a marvelous job and the bullet is very accurate.

[.41LC]

I think I could make it myself, or have them made on the CNC lathe at work, but thanks.

[Bent Ramrod]

Yes, I tried an extreme truncated-cone shaped hollow base for an Ideal 358495 to mimic the Hornady or Speer (forget which) swaged hollow-base wadcutters which seemed to swell and take the rifling in a .38 Long. It worked OK, but not as well as the swaged HBWCs.

Then I made a sort of rebated deep hollow base pin for the Ideal 45468, to try to turn it into a Minie bullet for a cap and ball .44. It was almost like a rifled shotgun slug, just a hollow dome of lead. The powder charge blew the fronts of the domes down the barrel, leaving the lead shanks in the cylinder, well glued in with black powder fouling. That was a long and memorable cleanup session.

I've also experimented with conical cavities in a .45 caliber mould I made. It wasn't accurate. I changed the base pin to a domed shape and it didn't help. Still trying to figure out what to do next on that one.

All in all, I think my hollow point pin variations are more successful than my hollow base variations. Almost ready to admit the factories might actually know what they're doing.

[Buckshot]

............The cavity in the base is obviously there for one reason only, and that's to assure obturation into the grooves to seal. I'll bet the Colt factory ran their tool and diemakers ragged making up test tooling and then checking by fire to make sure the slugs did what was wanted before making production tooling.

If it were me I'd try to find the dimensions of the original and use that as my initial attempt. It's all mechanics and tradeoffs anyway. Just like a Minie' design, the thinner and longer the skirt is the easier it will be to upset, but the negative is that at some point the pressure of the load may have pressure enought to 'blow' the slirt at the muzzle. A mechanical aspect is that the wider the grooves are, the easier it is for the skirt to upset and seal.

..............Buckshot

[Dale53]

I have had excellent results with solid wadcutters in both .44 (our 200 gr group buy) and the H&G #251 for the .38 Special. They require a bit more powder but come close to the factory HBWC's (.38) in accuracy and NEVER blow off a skirt (I have seen a couple of bulged barrels from trying to drive HB WC's too fast.

Further, the solid ones cast a LOT faster.

Just a thought or two...

Dale53

[.41LC]

I ended up fixing up the originals. I recut the hollow form on the same angle with a proper sharp base this time. They came out a little longer than originally, though overall shorter and I needed to shim them with washers. I'll be casting and shooting this Thursday weather permiting.