Hollow point geometry

[NoAngel]

I recently did my first hollow point modification on a 200g .359 round nose. I made a shallow but fairly large hollow cavity. I have seen many molds just the opposite. Deep narrow hollow cavities.

What's the school of thought on this?

I have a 356402 I'm pretty sure I'm going to hollow point next. Just curious which profile I should choose for the 356402.

[Beagle333]

Normally I like a big wide HP on anything slower, such as my cowboy .45s and .38s.

If it is going to be going magnum speed, say .357, then I want the deep narrow cavity. The big gaping HP's are pretty, but at high speed they just blow the nose off and shed their weight. If I'm going to speed it up, I want it to mushroom but stay intact. I don't know how fast your 356402 will be going... I don't load for 9mm.

[MtGun44]

Depends strongly on alloy hardness, brittleness and impact velocity. Pretty difficult to
make broad characterizations.

Deep cavities tend to open the boolit farther, if the alloy is soft enough and malleable
enough not to break off - and the velocity is correct. Too slow, no mushroom; too fast
and the whole front can blow off. Shallow cavities may do nothing if velocity is too low,
but for high velocities and harder alloys - it may be appropriate.

Only testing will tell.

Bill

[Sneakybuffalo]

Wide and shallow sounds more like a cup point, which has different effects than hollow points on terminal performance based on Flat Top and Mt. Sourdough's tests, although what you consider deep and shallow may be subjective. Pics are always helpful.

[NoZombies]

The earliest hollow point molds were ideal 'express' molds. They were designed in the era of black powder, and almost all of the bullets being cast were pure lead or a simple lead-tin alloy. They were marketed as having 'more killing power' on game, but mainly because they allowed a higher velocity, and I've never seen any early literature (doesn't mean there isn't any) that talks about expansion from the HP.

I've got a few of the early molds, and the designs love pure lead or 40-1 lead tin alloy.

[Ben]

I have a .44 cal. mold , Lyman 429640. I have 3 different HP pins to deal with the very things being discussed here. If the bullet is fired from a handgun , ( in my opinion ) it needs a different HP design than one fired from a rifle at up to 400 feet per second higher velocity. Having different HP pins allows for changes in the diameter and depth of the HP opening in the nose of the bullet, using the same mold.

The 1st photo is of the deep hp pin, notice how thin the nose walls are with this pin.


http://img.photobucket.com/albums/v494/haysb/011-17.jpg

Here is a view of the modified HP pin. I also have a flat pin that allows me to make a solid weighing 285 grs. The nose wall thickness of this one is quite different than the photo above !


http://img.photobucket.com/albums/v494/haysb/014-10.jpg


http://img.photobucket.com/albums/v494/haysb/015-12.jpg

http://img.photobucket.com/albums/v494/haysb/013-18.jpg

http://img.photobucket.com/albums/v494/haysb/014-9.jpg

http://img.photobucket.com/albums/v494/haysb/018-9.jpg

http://img.photobucket.com/albums/v494/haysb/019-5.jpg

http://img.photobucket.com/albums/v494/haysb/023-5.jpg

[Ben]

http://img.photobucket.com/albums/v494/haysb/028-1.jpg


http://img.photobucket.com/albums/v494/haysb/030-5.jpg

[NoAngel]

Wow, that's nice Ben. Some of the nicest castings I've ever seen.

I'm guessing you run the deeper hollow point at pistol velocities and the shallower one at rifle velocities???

[NoAngel]

The one I made will be for .357 magnum rifle. It's not as deep as yours.

http://castboolits.gunloads.com/showthread.php?257307-Look-what-I-did-today

[Ben]

Wow, that's nice Ben. Some of the nicest castings I've ever seen.

I'm guessing you run the deeper hollow point at pistol velocities and the shallower one at rifle velocities???

Yes , exactly.

[Ben]

The one I made will be for .357 magnum rifle. It's not as deep as yours.

http://castboolits.gunloads.com/showthread.php?257307-Look-what-I-did-today

Good thinking, it should not be. You don't want a " Blow Up" on impact.
You need some expansion, but you'll also need good penetration.

[NoAngel]

I cast them from aircooled 50/50. I'm hoping they will be malleable enough to expand and not fragment but hard enough to hang in there for the ride especially since they are plain base.
I will have to run them across my chronograph but I think 12.0g of 2400 should be fast enough get decent expansion.

[Ben]

Shoot them into water soaked old magazines.