Zinc Cast bullet Hardness remedy Question

[1322079]

After researching cast zinc bullets, one of the biggest issues is the hardness of zinc compared to lead, many people have stated that it would accelerate the wear of steel rifling. I have cast lead 45-70 rounds with ease in the past for my Marlin 1895CB but plan on experimenting with cast zinc rounds in a lee 500 grain mold which would produce aprox. 310 grain bullets. I am still new to the world of bullet casting so I'd like to hear from you guys.

So my question is that if I used undersized cast zinc bullets(.457) and then heavily powder coat them or paper patch them to .458/9-.460, will this reduce wear in my barrel and help mitigate the hardness of zinc? would the powder coat or paper patch act as a buffer to the steel barrel or would it make no difference?
Also, Marlin's have micro-grove rifling which I hypothesize will cause less wear than standard Ballard rifling, is that the case?



I'm just curious because lead where I live is becoming much more scarce. Also, lead free hunting 45-70 rounds are priced at over 2-3 dollars a round, so it would behoove me to find a cheaper alternative.

If this is deemed safe for my rifling(would cost way too much to replace a barrel), I plan on starting out with a approx 310 grain zinc cast bullet on 9 grains of Unique and then work my way to 12 grain for 1100 fps cowboy loads(trying to decrease wear).If this does not destroy my gun I plan to actually work up some hunting loads. So am I crazy?

Thanks for reading!

[swheeler]

If lead has a BHN of 5, zinc approx 50, copper/ gilding metal just over 100 what makes you think you will wear the barrel out? Most barrels are "shot out" by throat erosion not friction wearing the lands down, the lands are usually damaged by improper cleaning wear. I think you can shoot your zinc bullets until satisfied and then hand the rifle down to your children to shoot some more.

[longbow]

Personally I wouldn't worry about barrel wear from zinc. Depending on alloys both zinc and copper run about the same hardness from what I see and no-one seems worried about copper wearing barrels. Some zinc alloys are used as bearing materials so should not cause excessive wear especially if lubed. Again My opinion.

Not sure about thick powder coating but certainly paper patching should work and a large caliber like .45-70 seems like a good candidate for paper patching zinc... though again I wouldn't worry about zinc wearing a barrel fast.

Possibly of more concern is that you mention hunting and many if not all hunting regulations require expanding bullets which zinc is not, unless it is slotted like some of the solid copper or brass bullets and I'm not sure there is a malleable enough zinc alloy that would not break up in that format.

There have been a few people on the site experimenting with zinc bullets and zinc shotgun slugs. Hogtamer has successfully made zinc shotgun slugs and there have been a few people working on zinc for rifles. A search might turn up some useful info for you.

You guys are treading nearly new ground but I am sure there will be more activity in the "finding an alternative to lead" boolit casting in the future. Seems to me bismuth should be a good alternative as it has low melting point and fairly high density and bismuth is a common lead free shot material. Not sure of the availability or cost for boolit casters though.

Good luck in your quest.

Longbow

[swheeler]

If you have a copy of Hanloaders Digest 12Th Edition 1990(27 years ago) open it to page 128. The article is titled Shooting Zinc in Big Bores, by Karl Bosselmann, about five pages long with test data for Zamak cast bullets. Veral Smith made him 3 molds for the project, no grease grooves needed. 275 grain zinc bullets at 2690 fps" Accuracy potential looks promising with sub 1.25 inch 100 yard groups"

[1322079]

Thanks. Regarding the hunting "expanding" bullets, the lee mold is a flat nose, so in theory I could drill a shallow "hollow point" to allow it expand or deform. But that will need some DIY ballistics test on that theory. But lots of cheap hollow points, especially prvi partizan hollow points don't really expand much when shooting them in water, so as long as my homemade hp rounds do something they should be good for taking some game.

Zinc is considerably hard, but a brittle metal compared to copper and lead, so another possibility is to drill a small hole into 2/3 the length of the bullet to degrade its structural integrity when it hits something. Or combine both methods, a smaller hole in larger one to provide the least structural support. Since I doubt these bullets will go faster than 2200 fps in hunting loads, I don't think it should cause them to fall apart in mid air :)_

[Dusty Bannister]

You might just consider running your tests on a solid bullet before you get too carried away with deforming, unbalancing or otherwise destroying the integrity of the cast bullet. How much bigger do you need that 45 cal hole to be? I am on the road, but would look at finding out if zinc bullets ever expand. I recall reading in either Cast Bullets by EH Harrison or the ABC's of Bullet Casting that zinc bullets will not expand, ever. So you would only modify a bullet that will fracture and not penetrate. Also consider that a soft lead and tin bullet will expand, and a hard cast bullet will not expand much at all. If you are looking for expansion, you are not looking at zinc bullets.

[gwpercle]

A 45 cal. boolit with a nice flat meplate will need no expansion. I wouldn't worry about hollow pointing at this stage of the game. I have a gut feeling a 45-70 zinc boolit at a good velocity will be a good game getter.
I keep all my zinc WW's because one day someone will cut a mould that will drop properly sized zinc boolits and I'm going to try one .
Gary

[vepr12dude]

Some ammo manufacturers use zinc instead of copper for jacket material.....just sayin

[dbosman]

Zinc won't wear your barrel and you don't need lube coating or paper patching.

Slug your bore and size to groove diameter.