Bullet Casting Alloy

[farmer7]

Okay I think I've fried my brain reading about bullet alloys!

The only casting I do is pure lead round balls for ML revolver which i find fairly straightforward but I'm about to give casting .357 bullets a go. I've read so much about alloys and bullet hardness I don't really know what I need now! I understand bullet fit is very important.

The intention is to use them from a Marlin .357 at about 1050 fps or so for plinking. I've a huge heap of lead but no antimony/tin. What is the easiest alloy for a beginner to make that is hard enough to not lead much at around the 1000fps mark? Assuming I can get away with just adding tin what is the easiest source for that? Any other wisdom gratefully received!

And just out of curiousity at what speed could you get away with just pure lead in a .357?

[Alpha1]

Plumbers 50/50 bar solder is 50% lead 50% tin. Have a look on the cast boolits web site they have free cast boolit calculaters.

[Dahonis]

EBay or screwfix as a last resort. Try not to read too much into casting alloys.

The old timers did it around a camp fire....I have fallen foul of looking up a million and one different websites.

I use tin and lead successfully for the Mosin out to 600 yes.

[dromia]

Lead free solder will give you tin, you will need some tin for good bullet fillout no more than one percent is needed for that, 20 -1 lead to tin should be plenty hard/tough and not brittle.

I would work up in small batches of alloys increasing the tin content, or if you have any commercial hard cast bullets they can be added to give a little antimony and change the alloy type, antimony increases hardness alright but it makes the alloy brittle the more you add, antimony can also help with surface hardening through water quenching but I have never found a need to do that.

I use plumbers lead sweetened with a touch of tin in my 44-40 bullets and they are being driven to just over 1,100 fps over a case full of Swiss 3f black powder.

My universal alloy for everything except muzzle loading for velocities up to 2,000 fps is a around half and half mix of range scrap and plumbers lead, the reason for that is because that is what I have in abundance and in those proportions, it isn't critical and needs no formulas.

Get good bullet fit as you say you understand, a good lube like 50/50, then the bullet "hardness" becomes less of an issue, just beware too hard and alloy say over 14 BHN as this will be usually high antimony and therefore brittle, it is this brittleness that leads to leading.

However the better the bullet fit then the harder and more brittle the alloy can be as the likely hood of shearing is less with perfect bullet throat, groove, bore fit.

Don't overthink it, use what you have and experiment, if a batch doesn't work just melt it back down and re-use all you have lost is your time but it isn't wasted as you will have gained experience at the pot which will produce better bullets in the future.

[farmer7]

Thanks for the input everyone. Looks like i just need to source some tin and do some experimenting. And as you say Adam I can just remelt them!

Regarding solder something like this any good?

https://www.toolstation.com/shop/p81552 ... HxGGbBNwKy

It's 60% tin so 60g tin for £3.60.

Looking at the lead free solder it has some copper in it, 1% in a 500g roll, is that a problem or is it diluted enough?

http://www.screwfix.com/p/fernox-solder ... UQodpf4P4g

Thanks again!

[dromia]

Copper really helps with bullet toughness, as opposed to hardness, all my high velocity alloys have a copper content.

However too much is not good you just need a smidgen, less than 1%. I go for 3/5ths% in my high velocity alloys.

For your application copper is not critical just make sure that it is less than 1/2%.

[farmer7]

Copper really helps with bullet toughness, as opposed to hardness, all my high velocity alloys have a copper content.

However too much is not good you just need a smidgen, less than 1%. I go for 3/5ths% in my high velocity alloys.

For your application copper is not critical just make sure that it is less than 1/2%.

Thank you.

[andrew375]

Cheapest but probably not the easiest source is the backstop of your range. Most commercial cast bullets contain way too much tin and antimony for the purpose as they are cast from type metal alloys which are great for making well filled, shiny bullets that are hard enough to resist damage during transit. About 20% backstop lead to pure lead will give you what you need.

[Dark Skies]

I freely admit to knowing bugger all about the alchemy of casting beyond pure lead balls but what about sourcing some cheap beat up old pewter tankards to bung in the mix? Isn't pewter basically tin with a bit of copper and sometimes lead in it?

[farmer7]

Unfortunately I don't have a range to get range scrap. I do have some GM bullets which are blinking hard though so maybe I could chuck a handful of them in?!

I'll keep an eye out for some pewter tankards. In the meantime I got a roll of lead free solder which will get me going so hopefully will get some cast tomorrow.