So what’s the difference between 16:1 and 50/50 alloys?

[Tripplebeards]

Got me thinking as I finished mixing up some 16:1 today using pewter. It was originally 10.4 BH because of the pewter not being 100% tin. I ended up adding another 6 oz to my 8 pound mix finally getting it to 11BH which I think is what true 16:1 is.

I also use 50% COWW, 50% pure lead, and 2% pewter to the total for my 35 Remington hollow points. It gives me a BH of 10.5.

So if I would have left my 16:1 as is before I added another 6 oz of pewter it basically would have been the same hardness as my 50/50 alloy.

So is there an advantage to one or the other with both being the same Brunel hardness? I’m guessing the 16:1 might be a little more malleable and tougher because of the high tin content? I use these alloys in HPs.

Anybody compare these two alloys against each other for expansion and penetration tests?

[William Yanda]

Depending on the source of your pewter, the tin will be 90+% with the balance antimony and/or copper. That makes for a lot of room to guess about the results. I believe copper is alleged to add toughness, even is small quantities.

[Larry Gibson]

The difference is in the malleability of the alloy.

A true 16-1 alloy is a binary alloy of lead and tin with no other metals. This alloy will not harden by WQing or heat treating.

COWW alloy + tin is a ternary ally consisting of lead, antimony and tin plus some trace of other metals. It is the antimony that makes it harder when WQing or heat treating/

Your alloys composition with the dinnerware pewter is anyone's guess. Since it hardens to 21 BHN when WQ'd it probably has a good % of antimony and some copper.

Antimony in the alloy, especially if not in balance with tin at 5% each or less, while making the alloy harder also reduce malleability and can make the alloy brittle. That, in essence, reduces the alloy's ability to expand properly at lower velcocities.

When it comes to expansion with cast bullets the BHN is only half of the equation. Malleability is the other half.

[Tripplebeards]

Makes sense. The only reason I WQd my pewter the other day and in the past was to cool it off quick so I could immediately box it up and ship it out to a few buyers…and also to test my results on the alloy mix the other day because I was impatient to let it air cool first. I tried air cooling it yesterday and got the exact same hardness results of 21BH. So WQing it made no difference in making my dinnerware pewter harder. Same happened with the “16:1” I mixed up. WQ or AC I ended up with the exact same hardness. Both ended up at 10.4 BH at a 16:1 mix ratio. I was close to the 11 BH that I’ve read just about everywhere is what the hardness of true 16:1 tests at. What threw me for a loop is I almost had to double the pewter mix to get it from 10.4 bh to 11 bh. I tried 2 oz of 21BH pewter to my 8 pounds of mix and is still ended up at 10.4 BH. I added another 4 oz of 21BH pewter and finally ended up with 11BH. My guess I could have just mixed it 8:1 and called it done. Will next time around once I verify my pewter ignots are the same hardness before starting my mix. Gives me a good starting point anyway for next time.

So what ever is in my current dinnerware pewter alloy doesn’t harden with WQing.

So the high content of tin in true 16:1 alloy will make it a lot more malleable and hold together better in HP boolits vs 50/50 COWW and pure at the same velocities I’m guessing.

Sounds like a test in the making.