I'm coming to the experts here with a slightly off-topic question. I have read that lead-core jacketed bullets can be lubed and resized (for example, from 9.3mm/.366 down to .358) with a pass or two through a Lee resizing die. My question is: Can a copper bullet be resized? Using the same example, do you think I could successfully resize a Barnes 9.3mm TSX flat base down to .358. I thought I'd ask because I'm thinking that copper, soft though it may be, is not as malleable as lead. And that 286 grain TSX would make a heck of a .35 Whelen load. Whaddyathink?

Anything's possible, but it'll entail a lot of work with a stout press and a really stout bench. Do it in stages, no more than a couple thousandths at a time or you'll really be hating life.

One thing to consider when resizing that dramatically is the accumulation of fins around the base of the bullet. Look closely and if the fin isn't dead even the whole way around you're doing something wrong and creating lopsided bullets. Accuracy will be a sometime thing in that instance. Fins on the base in and of themselves are no friend to accuracy either- a fact proven 110 years ago in Dr. Mann's seminal treatise. The base is the steering end of the bullet after all.

gnoahh, interesting you mention Dr. Mann's book. I found a copy a few years ago and couldn't wait to dive in. Boy, it's loaded with info...and as dry as a math text book!!

To the sizing of a monometal bullet, I think you're going to need more than a bench press.

Thanks for the wisdom. I think I’ll cut my resizing teeth on some plain old cup and core bullets and we’ll see where it goes from there.

I've read that book over and over during the last 40 years. It is indeed dry reading, and I don't profess to having absorbed more than a percentage of its teachings. The thing that amazes me is that over the years since it was first published in 1909, people have persisted in asking the same questions over and over that were researched and answered in that book. I guess reading books is becoming a lost art anymore. Viva la internet where it's easier to get instant gratification whether spurious or not!! (He says with a touch of sarcasm.)

Gary, after being on the fire i have a great fear that not only do people not read books ,but their reading comprehension is non exsistant.

Op. Swaging will demand more then your normal press will afford you. I have swaged 458's to 454 and 452. It way as stated , a beast of an effort to do very many.
That said i did get a lee push through and rigged up a mount on my wood splitter to do it . Slow but effortless.
It is possible one could go in steps of reduction and do any desired.
I havent forgotten the promise of 45-70 data. I am having a bad MS day and havent made it upstairs to my gunroom. Will get that for you.
PS would love to see pictures of that FN 45-70. Rare conversion.
Tom

Hydraulic log splitter + Sizing die + ingenuity?

I regularly size .264 bullets down to .260 for an odd German round. C&H supplied the die for me and they go through pretty easy. From my readings over the years going beyond .005 can cause problems with the jacket spring back away from the more malleable lead.

Most of the solid copper bullets have relief grooves that would be lost when resizing.

I haven't read it "over and over" in the few years I've had it but, I have been through it a couple times and a few chapters a little more. By golly, he was nothing if not thorough!!!

I agree about the same questions being asked and deerstalker's comment about reading and comprehension. Why "comprehend" it when you can easily look it up again. That and the resistance to purchasing a loading manual and reading it baffle me. Methinks some actually need beat over the head with a book.

erich is correct about compromising the bond between core and jacket if sized much beyond .005. That's been my experience.

You beat me to it. Call Dennis at Fury Bullets and ask him about sizing jacketed bullets. He's only done it a few million times.

Thanks, Dinny

A buddy had a .44 Auto Mag and he sized down .45 FMJ to .44 in a custom die that he made with a long taper. It still took a stout press and quite a bit of effort.