optimizing a cartridge for zinc bullets

[TRX]

Assuming you were going to shoot zinc bullets in a rifle, what could you do to maximize their effectiveness?

Since zinc is lighter than lead, sectional density would be lower. I'm assuming the optimal twist required would also change.

I'm assuming something like a long, skinny 6 or 6.5mm bullet with a slow twist would be a reasonable choice.


If you were going to pick a bullet / cartridge / barrel combination optimized for zinc bullets, what would you do?

[7Acres]

Have you successfully cast or acquired zinc bullets?

[Whiterabbit]

what WOULD I do? I will tell you what I DID.

buy a 357 magnum single shot rifle I wouldn't mind goobering up (handi rifle), no modifications, and just shoot it.

FYI casting zinc sucks. If I ever get into it big, I already know what I'm doing for the mold. The mold heater ($20 hot plate) is gonna get a vibrating motor put on it. larger than a cell phone, WAY smaller than a tumbler. Maybe from a game controller. Enlarge the sprue just a smidge. Heat the mold RAGING hot and hold on the mold heater flat so it shakes. ladle pour with a heavy ladle I can heat up to ridiculous temps by letting soak in the zinc pot. Steer clear from bottom pour pots or anything that can clog. turn the mold upside down between pourings. Keep that sprue plate hot, hot, hot! keep the top of the mold hot!

There is nothing fun about casing zinc. Most fun part is having a bullet that looks like a 160 grain RN that weigns 92 grains. and may the Good Lord help you if you get any lead in your zinc pot. :o

[45 2.1]

Assuming you were going to shoot zinc bullets in a rifle, what could you do to maximize their effectiveness? Basically, you'll be shooting a FMJ bullet. Consider the nose flatness for effectiveness.

Since zinc is lighter than lead, sectional density would be lower. I'm assuming the optimal twist required would also change. No, length is the concern.... no change in twist.

I'm assuming something like a long, skinny 6 or 6.5mm bullet with a slow twist would be a reasonable choice. 30 caliber and make it go fast.


If you were going to pick a bullet / cartridge / barrel combination optimized for zinc bullets, what would you do? Try the 30-06.... use a single cavity iron mold..... cast hot and try to find one of the zinc casting alloys. Zamak (sp) for instance.

[Whiterabbit]

I suspect casting anything smaller than a 30 cal is gonna be hell for fillout. 35 was hard enough.

[Willbird]

Wonder if it would be easier to get fill out if you just had a bore ride bullet with one drive band ??

Bill

[nekshot]

this is a interesting thread. All I know is after expeirencing a little zinc contamination and getting everything clean and back to normal, I would give up and sell all my casting equipment and stick to jacketed bullets if zinc was all I could get.

[Whiterabbit]

I learned the trick is dont contaminate your ZINC with LEAD. melt 100% zinc. It's not fun to cast, but it looks just like solder or lead when in the melt.

I read somewhere that someone improved castability by going 50/50 with zinc and lead. Boy, was that ever a disaster! Lesson learned. Lead alloy OR zinc alloy, never ever ever ever both.

[TRX]

I'm thinking more along the line of using a friend's little CNC lathe to machine zinc bullets from zinc rod than casting, at least at the moment.

I'm still trying to get a handle on the parts of my old reloading manuals that I used to ignore - the bits about sectional density, twist, and drop, and how those would influence the shape of a lower-density bullet.

[Willbird]

I'm thinking more along the line of using a friend's little CNC lathe to machine zinc bullets from zinc rod than casting, at least at the moment.

I'm still trying to get a handle on the parts of my old reloading manuals that I used to ignore - the bits about sectional density, twist, and drop, and how those would influence the shape of a lower-density bullet.

As far as I can follow it twist is a function of bullet WEIGHT.....sort of, weight distribution can come into play too, it can make a bullet stable in flight with ZERO twist, like shotgun slugs with a heavier nose. But most rifle bullets are heavy in the rear not the front.

The weight of the bullet determines how much energy it carries to remain in motion against air resistance, so a lighter bullet the same exact shape will have a lower BC ?? It loses the same amount of energy, but it contains less energy...so it's battery goes dead faster (more like a capacitor than a battery actually hehe).

You might be able to make a two piece bullet with a zinc rear section and a lead alloy nose section that was stable in a shallower twist than an all lead alloy bullet ??

Bill

[TRX]

That makes sense, since the twist charts seem to be mostly about weight.

[Whiterabbit]

its about weight because the charts likely assume a particular density of lead.

Stability calculators always take into account weight AND length AND caliber. That covers density. If one shifts, then your stability shifts. Or more specifically, requires a shift in twist to maintain the same stability.