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Old September 12, 2012, 05:53 PM   #1
Mike / Tx
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Join Date: April 8, 2000
Posts: 1,368
Pouring HP's and Learning to Blend Alloy's....(bit long)

Being relatively new to the casting world, my initial goal was to simply produce some quality rounds to feed the appetite of my Raging Bull 454. That said I started out with the Lee 300gr RFGC 6 cavity mold. It was no small undertaking, as it involved close to a year of research, not to mention numerous questions and PM's on another site dedicated to Cast Boolits. It only took about a month and I was hooked to the gills. I started off with only a couple of molds, a bucket and a half of wheel weights and am now in up to my chin.

Since that time just over a year now I have laid in a goodly supply of ram materials, and purchased over a dozen different molds for my rifles and revolvers. I haven't gotten into the rifles just yet, but the revolvers, I am having a blast with. My latest acquisitions mold wise have been a few of the MP Cramer type brass molds. They are an awesome piece of craftsmanship for sure. The neat thing is that most come with at least a couple of HP pin options and when I get one I get all that are offered. They DO require a bit more love and care, but the result is well worth the effort. When you can sit down and pour out 20 pounds of alloy into almost pristine HP bullets, with little to no more effort in most cases than a VERY slight tap on the handle, you know your in the big league for sure.

This all said, with a HP verses a SWC, RN or RFN, you have to consider a few more things other than simply what the fit will be or which lube to use. You have to consider the velocity at which they will be driven, as well as what the expected impact velocity will be as well as what the intended target will be, in order to get proper expansion. Now this isn't to say that you cannot simply pour up a mound of HP from pure, or any of numerous lead/tin alloys, but you still have to do the trial and error thing to determine if the alloy is to hard or too soft.

I had purchased a couple of the LG Iso cores. I tried some of the alloy and found how well they poured, and how little work was needed, and went for it. They pour up the prettiest WFN's and RFN's you ever wanted to load up, as well as HP and any other style. The issue isn't with that, it's with the antimony being higher than the tin content which makes the HP a bit too brittle resulting in the noses blowing off even at the lower velocities. When drive to full magnum velocities they really don't stand a chance.

So my quest began in earnest to put together an alloy, using what I had on hand, and being able to duplicate it over and over, when needed. I started out downloading an Alloy Calculator spreadsheet put together by one of the other members on Castboolits. It is a very user friendly tool and while it will not get you down to the last increment of purity, it will get you in the cheap seats and you can at least enjoy the game. Most of the alloys listed on it were derived from known and tested alloy which can be purchased form Rotometals. This makes it VERY good for someone who wants to simply put together say 20 or so pounds of a particular alloy for a specific purpose, like HP's.

I took the spreadsheet and began to input numbers. It's all inf and well, but it uses pounds, so when you input ounces you have to use a decimal in the front. This isn't a big issue, but if your like me and formulas don't work with your brain, then you need a quicker method of figuring out what .0426 of a pound really is. That isn't a number I used but a good example of why the free download Convert for Windows is good to have stuck to your desktop.

After a few weeks of piddling with the numbers I found what I hoped would be a good match of tin, antimony, and lead. Since I don't have a big supply of either tin, or pure lead, I was working with the smallest amounts I could, and still have enough to pour up a batch of bullets for testing. Using the LG Iso Core alloy as my base I blended up my first batch. This one comes in at a 1.5/1.5/97 in percentages of tin, antimony, and lead. I had thought of going softer, but then considered that I would be driving some of these to Ruger only levels in my 45 Colt. (After all it is a Redhawk. ) After a bit of shooting over the weekend, I think I made the right decision.

So below is the link to the results of my initial testing, I would show the picks but this is probably long enough already. I will however throw in this teaser shot just for kicks,


Here are the rest,
Alloy Testing

I'm already working on one that will be just a touch tougher I hope, that will allow me to bump up the velocities for my 41, 44, and 454, well see soon.
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Mike / TX
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