Throwing a hotdog down a hallway

What happens when you send a very undersized bullet down a bore? I'm not talking about accuracy, I'm talking about what happens in the barrel? Could I use, say, a 38 cal bullet to fireform 348 brass into something bigger (.50-70 in my case)?

I find that when I use pistol powder with cornmeal, topped with wax to plug it, no space in case, the expansion results are underwhelming in the .50-70. It works fine in my 41 Swiss, but that is using soft PPU 8mm Lebel brass vs the hardy Winchester 348 Win brass I use for .50-70. Which, yes, is annealed at the neck/shoulder junction. Maybe I'm not using enough powder-- 8-ish grains of Win 244, that's my fastest powder on hand).

I have to end up getting the neck big enough that I can load up a .50 cal bullet with compressed BP, or even smokeless, and then it forms great, of course. But I'd rather use crap bullets I have lying around than my hand-poured 450gr boolits. Can I reasonably send 38 cal cowboy shooter pills down it that are enough to give it the resistance it needs to blow up that gat dang case as much as it should?

I know that it's possible to step it up with expanders, but at this point at least, I'm not committed enough to the cartridge to invest that much.

I have seen 223 fired in 6mm chambers to blow it out with no ill effects. A heavy cast bullet in a annealed neck with an appropriate charge of fast burning powder should do find. I would start low and work up to a load that just forms the case out. Going from 348 neck to 50 and the smaller body keeping the case centered may be tricky.

A tapered ex-pander may be able to open it up in one pass.its around .080 on a side.

One thing to watch is expanding that much the neck wall thickness is going to thin a bit.

A universal decap die could possibly be made into a neck expander

If you are worried about damaging your barrel, get some dead soft lead and cast a few projectiles with that. Muzzleloaders have been using unpatched dead soft lead for centuries with little to no damage cause by the lead.

I have a Blackhawk .357 convertible and shot .355 sized rounds through it with the only downside being keyholing.

What incremental sizing steps are you using to get the neck from.348 to .50? Seems like it would be similar to what me and others are doing with forming 348 into 45-75? I don’t like the thought of wasting expensive bullets for fire forming either so I bought some “cheaper” .458’s for that with “cheap” being an obviously relative term. I don’t plan on doing the COW thing either but that might change. I haven’t gotten that far yet.

I have shot a couple hundred .308/7.62x52 - both ball and tracer through a .358 BLR with no visible damage or loss of accuracy when shooting .358 bullets. I did have a lot of tracers, surplus 308/7.62x51 was cheap and firing it was the simple solution, in today's world, I pull the bullets save the powder (w846?) and use a couple tapered neck expanders (Lee EZ Xpander - Midwayuse) for neck expanding. Another way is to put 5-10 grains Bullseye/TiteGroup/other fast powder, fille case with Corn Meal or Cream of Wheat, plug with a wax wad and fire.

I use 9 gr of Unique with cream-of-wheat and a wax plug to blow .30-30 shells out straight for my .38-55 shotgun. It looks like W-244 is close on the burn rate chart; if anything, a little slower.

I did my “load development” for the blank loads in a similar way I do with actual rounds, except individual incremental increases instead of 5-shot groups. Each shell with a little more powder than the last one; fire until the walls are straightened out satisfactorily, watching for excess pressure signs every firing. Where you start is kind of an arbitrary judgement call, since there aren’t (AFAIK) fireforming charts for every cartridge. I anneal the shells well down the sides. My general rule of thumb is fireforming for necking up; dies for necking down. There are exceptions: I expand .30-30 necks for .32 Special, but find that anything much larger starts giving off-center necks and uneven mouths.

You might get a little leading with the undersized boolit rattling down the barrel, but I can’t see a safety issue as long as the barrel is clear for the next shot. I wouldn’t bother with a bullet loading, myself, unless I was “improving” a cartridge of the same caliber.

It could be that I am just not understanding exactly how people are expanding necks with mandrels. MostlyLeverGuns, you mention the Lee EZ X expander. I see it on their website, and they make it seem like all their full length dies come with it. How exactly are you using it? Do you have dedicated dies?

So far, I've just been trimming necks down a bit to get them closer to the 1.75" I need and then load up pistol powder, cornmeal, then plug the neck with wax. That gets me some expansion, enough to use the Lee universal flaring die to get the mouth open enough to seat a 50 cal bullet. (https://leeprecision.com/universal-case-expanding-die).

Typically, I'm getting the case mouth close on the first go, but the body is still very unevenly expanded. It's not until I fire a close to normal load that I get the rest of the expansion.

Assuming that you are using boolits, you get severe leading in your bore. Be prepared for a lot of scrubbing.

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Originally Posted by Sasquatch-1

If you are worried about damaging your barrel, get some dead soft lead and cast a few projectiles with that. Muzzleloaders have been using unpatched dead soft lead for centuries with little to no damage cause by the lead.

I have a Blackhawk .357 convertible and shot .355 sized rounds through it with the only downside being keyholing.

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I always wondered about how the Ruger did with the 9 mm cylinder

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Originally Posted by RonnieMilsurp

It could be that I am just not understanding exactly how people are expanding necks with mandrels. MostlyLeverGuns, you mention the Lee EZ X expander. I see it on their website, and they make it seem like all their full length dies come with it. How exactly are you using it? Do you have dedicated dies?

So far, I've just been trimming necks down a bit to get them closer to the 1.75" I need and then load up pistol powder, cornmeal, then plug the neck with wax. That gets me some expansion, enough to use the Lee universal flaring die to get the mouth open enough to seat a 50 cal bullet. (https://leeprecision.com/universal-case-expanding-die).

Typically, I'm getting the case mouth close on the first go, but the body is still very unevenly expanded. It's not until I fire a close to normal load that I get the rest of the expansion.

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I think that Lee die is more for slightly flaring the case mouth for cast boolits. What you need is a series of expanders that will step the neck up in increments combined with annealing periodically. I’m pretty sure there’s a company that makes mandrels that work with the Lee expander. Let me go find that and I’ll get back to you.

https://noebulletmolds.com/site/prod...er-plug-rifle/

Call them and confirm they work with the Lee expander die. I’m 90+% they do.

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Originally Posted by Gav-n-Tn

https://noebulletmolds.com/site/prod...er-plug-rifle/

Call them and confirm they work with the Lee expander die. I’m 90+% they do.

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Oh cool, thanks!

Though this still only gets the mouth opened up. The body still has to expand considerably, which is the problem I'm having.

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Originally Posted by RonnieMilsurp

Oh cool, thanks!

Though this still only gets the mouth opened up. The body still has to expand considerably, which is the problem I'm having.

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You may have to fire form several times? Is that the best donor case for what you’re doing? I don’t know enough about it but, I know you’re trying to form a straight wall case. If the 348 doesn’t work for you, I’d be interested in the brass.

I go from 30 cal to 36 cal in one pass making 357 herrets with a tapered expander.
The tapered expander is just what it says. An expander ball as a narrow band at caliber to open necks when pulled out. The tapered expander may have a working surface an 1" long and taper from case caliber to the finished size required or slightly bigger to size back down. Its usually 1 pass but may be 2. You run the cases over it and then full length size to set other features.

I use the Lee EZ Xpander in the Lee Decapping Die. I have several Lee Decapping Dies with different Lee EZ Xpanders, 8mm, 338, 358, 375, using them to expand necks in steps for 308 to 358, 30-06 to 35 Whelen, 30-30 to 375 Win, others. I also expand some necks a size or so larger than the caliber of the cartridge, then size carefully for rifles with 'generous/excessive headspace'. I do lubricate the inside case neck using a Q-tip and Hornady Unique Case Lube. I also anneal, sometimes during, sometimes before, and always after any significant case/neck forming. For rifles with 'generous' headspace I will lubricate the the case and fire moderate loads, allowing the case to form in the chamber avoiding or lessening the 'stretch ring' or head separation found in brass fired in long chambers. Careful adjustment of full-length sizing dies or the use of Redding Competition Shellholders then extend brass life significantly. Some Lee Sizing dies do come with the EZ Xpanders, I think the 338 Federal, 358 Win, probably others.

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Originally Posted by RonnieMilsurp

It could be that I am just not understanding exactly how people are expanding necks with mandrels. MostlyLeverGuns, you mention the Lee EZ X expander. I see it on their website, and they make it seem like all their full length dies come with it. How exactly are you using it? Do you have dedicated dies?

So far, I've just been trimming necks down a bit to get them closer to the 1.75" I need and then load up pistol powder, cornmeal, then plug the neck with wax. That gets me some expansion, enough to use the Lee universal flaring die to get the mouth open enough to seat a 50 cal bullet. (https://leeprecision.com/universal-case-expanding-die).

Typically, I'm getting the case mouth close on the first go, but the body is still very unevenly expanded. It's not until I fire a close to normal load that I get the rest of the expansion.

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Look in the Vendor Sponsor section in RIX
This stepped expander can be had in any size needed and will fit a die body you have now.

Oh, thanks, Chill Wills! And everyone else as well.

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Originally Posted by RonnieMilsurp

What happens when you send a very undersized bullet down a bore? I'm not talking about accuracy, I'm talking about what happens in the barrel? Could I use, say, a 38 cal bullet to fireform 348 brass into something bigger (.50-70 in my case)?

I find that when I use pistol powder with cornmeal, topped with wax to plug it, no space in case, the expansion results are underwhelming in the .50-70. It works fine in my 41 Swiss, but that is using soft PPU 8mm Lebel brass vs the hardy Winchester 348 Win brass I use for .50-70. Which, yes, is annealed at the neck/shoulder junction. Maybe I'm not using enough powder-- 8-ish grains of Win 244, that's my fastest powder on hand).

I have to end up getting the neck big enough that I can load up a .50 cal bullet with compressed BP, or even smokeless, and then it forms great, of course. But I'd rather use crap bullets I have lying around than my hand-poured 450gr boolits. Can I reasonably send 38 cal cowboy shooter pills down it that are enough to give it the resistance it needs to blow up that gat dang case as much as it should?

I know that it's possible to step it up with expanders, but at this point at least, I'm not committed enough to the cartridge to invest that much.

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Check the threads in your loading dies ! I have an RCBS die that has a 9/16 inch NF thread (.520" x 18TP)- all you need is buy a long bolt at the hardware store, a buddy with a lathe or can even do the taper in a drill press, need two or three increments of expander die to fit that thread - make em with longish taper a glass smooth polish on the working part. The price of powder and primers these days makes this a way better alternative if you have the die body (or can borow one) to start the process - (mine is part of a RCBS 45/70 three die set )

i DO JUST WHAT YOUR DOING TO GO FROM 358 TO 11MM wERNDL. sry 10 grns Unquie cream or wheat full, twist of TP to plug - frie straight up. Never gets the body up but neck is good to go, needs another cull bullet to blow out fully. As for you question, I cant see that it would hurt anything, but I am sure it would help either. maybe as has been suggested, load a case and muzzel load a heavy size ball on to it. I suspect all the expanders will stretch your brass on the weaker side more. I could be wrong.