by wildcatter » Wed Mar 03, 2010 5:58 pm
You can size down, anything to anything and you already have the right ideas, Man-is-that-going-to-take-allot-of-time!!
I have been resizing down bullets since I was a child and prolly have as much or more experience doing it than anyone alive (and before I started to suggest, that our guys do this, I knew of no-one else doing it), considering that there is no data in the literature anywhere about it, other than it's dangerous and even that admonition is so rare you might spend more time than you've got trying to find it. - Flash, at this years SHOT, one of the suggestions Hornady solicited me for (yup, they asked me), was for them to resize their 325gr 458FTX to 452, and to offer it in their Dangerous Game Line, they loved the idea, which was one of many I gave them.
There are many considerations, but let's consider your 375 to 338. For the most part, most of those bullets, will separate the jackets before you get to 338 and if you did get to the end results with them en-tact, most of those will have Terminal Preformance jacket/penetration problems. I'm not saying you can't do it, I'm saying there are a plethora of problems to consider, Safety being the biggest.
For the most part, but not always and not even usually, one can go from one caliber to another. Example, 8mm to 7.62, or 35cal to 338. In fact I regularly shoot 9mm bullets from my 338 and .358/.357 bullets in my 9mm is just a complete snap and I don't even resize those, the throat and barrel does it, you just need to make sure the 9mm doesn't expand so much that it doesn't chamber and of course use less powder. You ought to see my chronograph numbers when I am shooting resized 80-90gr 9mm hollow-points at 3500fps+++, for my 338. As for the fauna, you are well aware of what the Varmint guys call the Pink Mist, is all about, imagine a wood-chuck hit with the bullet I just described, some of which have reached 4000fps+ (don't try that until you've got more experience than I). These bullets are designed to expand at 300fps or less in a 380acp, now move them at WELL more than 3000fps. In most cases you only find a wet spot where they were!
I've long used 357 lead semi-wad cutters, flipped over and hand pushed into the case mouth of a 7mm remmy-mag, with 10gr of 296, filling the cast up the rest of the way with Cream-of-Wheat (this or something like HAS to be done with highly reduced loads, to keep the gun from blowing up), and then firing them in my 338. Leading is one of many problems, but several shots with jacketed 338 bullets cleans that all out..
Now, I bet this will all spur on many questions, bring'em..t
Safety First..t