Zinc Mould Question

[Johnch]

OK 2 of my "Friend" are getting me wheel weights
But as I have been up to yesterday not able to do much
I sorted several 5 gallon buckets and found my Free Lead WW's were mostly Zinc and some steel , with only ....maybe 10% lead WW's
Also a fair amount of valve stems .... not fun to have them in the mix when I smelt the WW's down

So I got to thinking about cutting a 30 cal mould to cast some bullets to shoot out of the FAL
As I have a good amount of Zinc WW's and I have a pot that I had been using to cast Zinc Decoy anchors

As I am just starting , I got to thinking
As the Zinc is a lot harder than lead
Should I put groves in the bullet , like the X-Bullets
Not planning on needing lube as I was planning on powder coating them
But don't want to run into a pressure problem as I was hoping to work up a load at or close to 2000 FPS

Thanks

John

[country gent]

I would cut the grooves maybe somewhat between a true grease groove and tumble lube. A little on the shallow side and maybe a 10*-20* ancle so they release from the mould easily. I would also use steel or cast iron for the mould blocks since the zinc is going to be hotter than lead and might soften an aluminum mould. Al;so zinc and aluminum will alloy together so zinc may want to adhere to aluminum blocks. Grooves might not be entirly neccesary. Even a all zinc bullet wont be quite as hard as a jacketed or all copper slug is. But they may help with finning on the base and some other Issues. If possible cut the grooves .010 - .015 deep on a side or so. This should be enough for powder coating and may hold enough lube if you decide to go that route. I pl;ayed around with zinc pistol bullets years ago, with few decent results.

[runfiverun]

zinc don't need lube treat them like a copper jacketed bullet.

[Johnch]

OK thanks
Guess I just figured Zinc bullets would need a lube

John

[gwpercle]

I have been saving all my zinckers because one day somebody is going to come up with a way to make moulds to cast boolits out of zinc , they will not lead and will not require lube or powder coating. All these "free" zinc weights are just waiting for a proper mould...someone will start making them !
Gary

[yondering]

I agree that zinc cast bullets for something like an FAL could be pretty useful, and I think you could expect them to shoot pretty well with the right design. Be aware though, they'll penetrate steel pretty deep, because they are hard. Even compared to FMJ, zinc bullets are harder than the core of jacketed bullets.

You can certainly cast with zinc in brass and iron molds. Keep the pot and the mold hotter than you'd normally do with lead, and break the sprue as quick as you can, it gets hard to cut otherwise. If you have the option, a smaller sprue plate hole is a good idea.

I'd probably go without any lube grooves at all if you're making a mold (a lot easier to make that way too!), but if you want to add grooves, consider making them very shallow, like small bore rider sections.

FYI molten zinc does dissolve aluminum. I have cast a few in aluminum molds, but you probably don't want to make a habit of it.

[too many things]

DONT try zinc in brass you will have a scrap mold it will bond to brass in a heart beat

[yondering]

Good point, that makes sense! I thought I'd cast zinc in a brass mold once, but probably not now that I think about it.