Sub sonic and Supersonic from the same mold?
Yup! As I continue my endeavors in casting with zinc I wanted to show casters that the dreaded Zn label on wheel weights actually makes some good bullets!
Like the majority of us here who have a few years of reloading, I will admit that my reloading adventure hasn’t saved me ANY money. The rabbit hole just gets deeper. But hey, a man has to obsess over a hobby to stay healthy…why not this one?
Where I can see savings in casting with zinc is on big bore pistol and rifle cartridges. Zinc bullets can duplicate what copper bullets can do such as a Lehigh Penetrator. If one can make a mold similar the weight and performance will be similar. I actually managed to cast a 75gr HP zinc bullet in 9mm that travels at 1800+ FPS. The gel test showed devastating results and ballistics similar to a G2 RIP round in 9mm. Plus, being capable of self-sufficiency is a priceless trait to have and not wait for those manufacturers to ship you those reloading bullets.
Pros and Cons…
Well here’s my honest take so far on Pros
Fills the mold similar to pure TinDon’t have to lube or powder coat, just size/load/shootFragment on steel; good for close range steel shootingAnother viable casting metal, often thrown awayVelocities well above anything listed. An example of where this could be a benefit would be timed shooting events where milliseconds matterSuper light recoilHard enough to load like a FMJ, soft enough that it won’t cause erosion or barrel wear (explanation below)Steel molds handle zinc like leadNatural lubrication and removes fouling in barrels
Ok and the Cons
Zinc reacts with aluminum, so not good for aluminium moldsRequires high heat (over 800* F), again not good for aluminium moldsWill eat through a Lee 4-20 Pot… Just ask Elvis AmmoCast bullets that are 60% of the lead weight, so if shot in a rifle with a fast twist you may not see accuracyYou may be shunned or cast out of the Cast Boolits Forum if you even mention experimenting with zinc. Oh well, TRN is better any how
Zinc won’t wear your barrel
This is probably the most oft repeated statement I have heard. Let’s look at some facts. Pure zinc itself is roughly around 30BHN according to http://www.engineershandbook.com/Materials/zinc.htm
I had a sample of my ingots tested by LTI and results of my Zinc Wheel Weights came back to being close to Zamak but with a lot lower aluminum resulting in an average BHN of 45-50. So with these results stated…
Copper runs about a 114BHN; that is significantly higher than Zinc Wheel Weights. Manufacturers that produce full copper bullets actually undersize a majority of their bearing surfaces or engineer in a band, sometimes advertised as a “sealing” feature. The truth is obturation on a very hard material such as copper, if the copper bullet were sized at traditional size, will cause major pressure issues and barrel wear/damage.
Well zinc does the exact opposite. Zinc has a natural lubricity attribute to it, hence why it’s used in many bearings. It’s also soft enough to obturate and squeeze down our barrels without pressure issues or wear in rifling. So far I have shot over 3,000 rounds of 9mm made of zinc. I compared a recently slugged bullet with one done when I first started casting. Measurements are exactly the same. I also made a dummy FMJ bullet that acts like a Go/No go gauge. The depth micrometer showed no throat erosion.
Well what are your thoughts? Comment below!
As always, much appreciation for watching. Hope this sparks some ideas!