Cast mold in .402 size that has a large single flute hydraulic nose

[Oldfeller]

Logically, a single flute (relatively large) fluted nose system could be operated by simply opening and closing the mold.

Resulting water dropped (relatively hard tough WW slugs) could be powder coated and put through a LEE push through sizer nose first to readily yield finished sized slugs ready to put into a case.

Simplifying the thought a bit, a huge single large flute could be designed to align with the mold parting line such that you got maximum tissue displacement effect by a huge flute area and a reduced "as cast" weight for faster bullet travel.

The cast lead slug would be forced out of shape during impact, but would still perform better than most hollow point lead slugs resulting in large tissue damage and relatively deep penetration.

This is a thought for discussion, or if such a mold exists we could ring in the mold maker for the practical aspects of what he can do with the idea.

[Oldfeller]

Why 40 cal? This idea operates off of bullet speed. 40 cal has the needed speed, with 10mm ramping up the effects accordingly.

A larger size helps make developing a new idea easier ..... trying to start things at .355 diameter complicates things right at the start.

[Bigslug]

Can you clarify what you mean by "single flute"?

I assume you're suggesting one of those "Phillips head" points with a depression on only one side? Would this not be a horribly unbalanced bullet?

The FBI lab rats concluded that tissue displacement is not an effective method of causing damage in elastic tissues until the impact speed reaches @ 2,000 fps. Up to that point, the tissues simply stretch out of the way and snap back. The conclusion they came to is that we can really only count on handgun bullets damaging tissue within the span of their own diameter - effectively, if the bullet doesn't touch it, the bullet doesn't hurt it.

That's the current scientific thinking, anyway. I've pondered on the screwdriver bit nose concept as possibly a way to compress tissue in a way that makes it behave like the impact speed is higher than it is, but this seems like a very large ask from cartridges that are barely capable of exceeding 1,000 fps.

I think the answer you seek already somewhat exists in the form of the Barnes TSX and TTSX copper hunting bullets. These expand into four petals that increase the effective diameter and cut like an archery broadhead. Because they don't have the full frontal surface area of a 360 degree mushroom, penetration is not compromised as much. With an impact at over 2,600 fps, I can attest to the fact that they also deliver a displacement effect, but I think with pistols, we're back to what we can accomplish with the comparatively gentle push through, and maintaining ability to penetrate by not turning the bullet's nose into a parachute.

The way to create a Barnes in cast form would probably be a modification of the "penta point" concept. Experiments should run in the direction of playing with number of petals and shaping the inside of the cavity so those petals are reinforced and less likely to peel off. The old PMC Starfire bullet might be a decent inspiration, though that's clearly a swaged or nose-punched bullet - duplicating it in cast would be. . .problematic.

Increase diameter without increasing frontal resistance. I think that's the ticket.

[Oldfeller]

Yes, a single flute or scoop would make for an unbalanced bullet. However, it takes ~25 yards~ for the yaw effect to show itself as major dispersion effect, so any strike at a distance shorter than this would still be point on.

Still not optimal, but you get what you can from the idea. 1000 fps would get some splash effect in soft tissue.

But yes, two flutes could make for a much more balanced "as cast" bullet .......

Still, the cast lead bullet form would not likely survive the impact without getting wadded up to some degree and with the post impact bullet beginning some severe tumbling resulting from the flesh jet effect.



Flat meplat .402" slugs already exist in 40 cal world, so unless we can improve upon them using hydraulics then we've already got what we can get in a readily cast bullet.

As far as fancy copper bullets with fold out sides, that sounds like some fairly expensive stuff to me.