Fire-forming oddity

[RonnieMilsurp]

Hi there. I'm in the process of forming some .348 Win cases for .50-70. I'm working with 10 cases as a test run. First off, I think I got a bit too eager because I forgot to anneal them. But, other than that, my process was the same as I did with my Swiss Vetterli with Lebel cases: a few grains of pistol powder and the rest full of corn meal, capped with wax, and fired upward to keep the powder by the primer. I did not trim any length off of them before fire forming. This worked fine in my Vetterli.

Every single case came out asymmetrical. That is, on the side that faced downward in the chamber, the wall of the case blew out straight/correct. But on the opposite side, the .75" or so of wall that's towards the rim didn't blow out all the way, but as you get closer to the mouth, it does. I know that the chamber itself is symmetrical because I cast it with Cerrosafe.

The only thing I can come up with is that the block is allowing for uneven head clearance, so the case gets tilted when fired. Though that doesn't explain why the mouth (last half inch or so) of the case seems to blow out more normally. I was able to run them through a full length sizer afterwards, but obviously it can't push the walls out. I even took one and repeated the fire-forming process but turned the case 180 degrees, only to have it come out looking just as it went in.

I'm sure there's something I'm missing here but can't think of what it is. My "screw it" mindset almost let me do a nearly full load of BP with a real boolit just to force it to form the rest of the way, but thought that I'd better ask here first.

[Gewehr-Guy]

You might try the O-ring trick, slide an o ring against the rim so when the breach block is closed, the rim is tight against it. I think the mouth expands better just because it is much thinner than the shoulder portion. Can you find the proper 50-70 brass, they should be cheaper than .348 ? Once a case expands unevenly, it usually keeps expanding on the thin side.

[bertus534]

I cut my 348 cartridges to size with a trimmer anealed them,can be done with temprilac available from brownells or dip them in your lead pot,after that I gently flared the case mouth and anealed again .load the cases and Bob is your uncle. Hope this helpt Oscar



Verstuurd vanaf mijn SM-A127F met Tapatalk

[BK7saum]

Did you actually fire them with muzzle pointed straight up? i fire formed some 7.62x39 to 401 wsl and they fireformed best with muzzle up. With barrel horizontal, i got uneven fireforming like you are seeing. I would not have thought it would make a difference. I would likely try a little more powder to bump the pressure.

[RonnieMilsurp]

BK7saum, well...not perfectly vertical. I had to get it out past the roof over the benches at the range. Will try more powder.

Bertus: I didn't trim first because I didn't want to over trim them. Made that mistake with my Vetterli.

Gewehr: I may try the o-ring. And no, this .348 brass was significantly cheaper than any .50-70 I've seen.

[bertus534]

I made a chambercast first so I knew
to what length to trim

Verstuurd vanaf mijn SM-A127F met Tapatalk

[Bad Ass Wallace]

Been fireforming 348 for a long time, use expanders, 375, 410, 458, 510 in gentle steps.

https://i.imgur.com/AFxNupph.jpg

[indian joe]

Been fireforming 348 for a long time, use expanders, 375, 410, 458, 510 in gentle steps.

https://i.imgur.com/AFxNupph.jpg

+ 1 to Wallace - gentle steps

50 alaskan brass was available about a year ago, that would be much easier if you can find it

I formed 348 to 45/75 - blew em out using full case blackpowder and a proper lead boolit - accuracy was quite acceptable and the trigger time did me good

be aware 348 winchester cases are way under (10 to 12 thou) SAAMI spec so you end up with a goofy lookin coke bottle deal at the back end so if you can accomodate the "O" ring idea I would do it .

[RonnieMilsurp]

What do you mean by coke bottle thing?

Question for all: should I just abandon these 10 cases or will they be ok to fire with a full load?

[uscra112]

You might try the O-ring trick, slide an o ring against the rim so when the breach block is closed, the rim is tight against it. I think the mouth expands better just because it is much thinner than the shoulder portion. Can you find the proper 50-70 brass, they should be cheaper than .348 ? Once a case expands unevenly, it usually keeps expanding on the thin side.

O-ring or a few 1/4" wide wraps of packing tape just next to the rim to keep the base centered. S.O.P. here.

Yes, those cases are spoiled, IMO.

[TD1886]

If you feel it's not locking up even go ahead and use the O ring trick. Other they that I would say if you have enough pressure with the light load sligthly oil your whole case. You'll be surprised even without annealing.

[RonnieMilsurp]

Oil it with... gun oil? Motor oil? Gear oil? What's the theory there?

[uscra112]

Oiling will let the shoulder of a rimless case that's too far back be pushed forward again. I kinda doubt it would help with the O.P.'s problem.

[TD1886]

Oil it with... gun oil? Motor oil? Gear oil? What's the theory there?

Any light oil like gun oil or even Imperial sizing wax.

[TD1886]

Oiling will let the shoulder of a rimless case that's too far back be pushed forward again. I kinda doubt it would help with the O.P.'s problem.

I've done it, it helps out with the web area of the case to fill out evening. This is one way for form a 350 Legend from 5.56 cases, which is kind of dumb to start, but it works. My friend told me of it and I tried it and was a perfect fire form. That tape trick is what I use to get 30-06 to work in the 6.5x55 Swede. 1/8th inch strip right around the solid web part. Bitch to load into the chamber, but the 06 cases comes out perfect.

[indian joe]

What do you mean by coke bottle thing?

348 cases are .542or so at the base - 45/75 chamber spec is .554-6
348 cases are tough brass so it took me several fullcase blackpowder loads to get them blown out right down to the solid head - happily my chamber neck is neat enough that loaded rounds stay centered (at the rear) in the chamber rather than lie to the bottom --along the way they did exhibit a distinct coke bottle look tapering from halfway along the body back to the unexpanded base - had the neck clearance been (as in most rifles) insufficient to orient the round and all the expansion was to one side they woulda looked kinda fugly

Question for all: should I just abandon these 10 cases or will they be ok to fire with a full load?

dont toss it until its irretrievable - do you have access to a 348 FL size die ? resize and start again might work

[deces]

https://www.whiddengunworks.com/hydraulic-form-die/

[uscra112]

I reckon I can fireform an awful lot of cases for $258.99 worth of powder and primers.

[deces]

I reckon I can fireform an awful lot of cases for $258.99 worth of powder and primers.

:bigsmyl2:

[RonnieMilsurp]

dont toss it until its irretrievable - do you have access to a 348 FL size die ? resize and start again might work

I do not. What's the potential problem with just firing it with a charge of BP and a bullet? Is the idea that the case wall is now too thin somewhere and could blow out? If so, what part is supposedly thin? The part that blew out like it should or the part that didn't?

Or something else entirely?

[indian joe]

[QUOTE=RonnieMilsurp;5608560]I do not. What's the potential problem with just firing it with a charge of BP and a bullet?

cant think of one ....348 winchester brass is some of the toughest you will find
mark the base or cut a little nick in the rim that lets you orient the case in the chamber so the bulged side is down and straight side up

I made a couple hundred 348 cases over to 45/75 without hassles - pretty much followed Wallaces' system - step by step slowly with expanding dies - I annealed twice - first time before I started then again towards the end - made the expanders out of some high tensile bolts - I found a match up for the thread in a RCBS die body then turned the bolts in the lathe - you could do it in a drill press ok - make em with a gentle taper so the end is just small enough to enter the case neck without swelling it - works like a pilot and keeps things all straight.

.......

[RonnieMilsurp]

Thanks. If I end up going this route, what rating of bolts did you use? I'm still a bit hazy on how to identify strength vs hardness. From what I can tell, a grade 8 bolt has high tensile strength but may or may not be hardened. I've tried turning a hard bolt in a drill press before...I don't have that much spare time. :D

[TD1886]

I reckon I can fireform an awful lot of cases for $258.99 worth of powder and primers.

That was my largest complaint about doing it that way. I didn't do very many that way.

[RonnieMilsurp]

Just did 2 more from fresh cases. Put about 1/8" of tape next to the rim to fill out the space in the chamber. Upped the powder half a grain, pre-trimmed the case. Fired exactly vertical. Got the exact same results. I even re-cast the chamber to make sure I'm not crazy, and it looks normal. Straight walls, just like Mr Springfield intended.

I am putting 6 grains of Win 244 (don't have Trail Boss or any shotgun powder) and filling the rest pretty tightly with corn meal, then capping with wax. The only thing I can think of is that the powder is still settling to one side when I chamber it, even though there shouldn't be much room for things to shift. It's definitely always the top of the chamber that doesn't expand for the first inch. Then it blows out evenly for the last .75".

316674

[hpbear101]

I used 348 case in my 1868 Springfield for many years until I was able to buy some Starline cases. The 348's are a little small at the base so they will always have a bulged look to them. The rims are smaller as well and were prone to slipping past the extractor (I also had a few cases that were given to me where they used a die to swaged the rim bigger they worked great). I bought a replacement extractor from Dixie and built it up slightly with a little silver solder and it work pretty well. I put the original back on when I acquired proper 50-70 cases.

I have a bag of dental rubber bands for braces. I put those around the base of a case that's a little small when I am fire forming. I used to use 38 special brass in a 41 Colt, they looked about like your cases but they worked quite well. If you can expand the mouth and get a bullet seated I would fire the cases (with tape or rubber band around the web) they should form o.k.

[uscra112]

Could the extractor be forcing the base off center in the chamber?

[deces]

It looks like a straight walled case, can't you just get a lee expander ball to open it up all the way down?

[uscra112]

Good idea, but would have to take into account that the .348 case wall thickness will taper. So the expander plug would have to taper also.

[deces]

Oversize it with the expander, then size tapper back with factory die.

[RonnieMilsurp]

I'm pretty new to the fire-forming-semi-obsolete-cases world, so forgive my ignorance. Is there a reason why not just blowing it out with an actual load isn't perfectly good? Honest question.

I find that I can fit 35 grains of Pyrodex comfortably without having to compress the powder at all. I'm running 450gr Lee bullets. I loaded up two to see what happens. Some are a bit thin at the mouth, I figure actual pressure should flow the brass towards the mouth, no?

[uscra112]

Lotta people do fireform with a near-full load. It's the final step in my process of making .22 Lovell out of .223. Ironically these loads are sometimes even accurate.

[MostlyLeverGuns]

Lee makes EZ Xpander Decapping pins that have very long gentle tapers in many calibers, about $5 each at MidwayUSA. They would be start to get to .50. They have a.50 BMG tapered but do not know if it would fit in standard Lee decapping die. Might be easier than machining your own. Even mild steel would work for simple neck expanding, high polish with an easy taper, go in steps. A wrap or two of tape for centering and fire forming should help final product.

[uscra112]

If you use those Lee expanders, buy a collet nut for each one. You will wind up welding the stem to the nut once you have it adjusted. No amount of abuse with long-handle wrenches will keep them from slipping when used for reforming brass. Ask me how I know. :mad:

[Moleman-]

+another one for the expanders Wallace mentioned especially on straight walled cases. With the price of primers and powder it saves money also. I deer hunt in one of the goofy straight walled cartridge areas and usually with some sort of wildcat based off of a bottleneck case. This year it's 375 win from 30-30 cases. The first time they're getting fired it's as loaded 375.

[indian joe]

Thanks. If I end up going this route, what rating of bolts did you use? I'm still a bit hazy on how to identify strength vs hardness. From what I can tell, a grade 8 bolt has high tensile strength but may or may not be hardened. I've tried turning a hard bolt in a drill press before...I don't have that much spare time. :D

I used grade five (carbon steel) but a plain old bolt would probably work fine - more important is a smooth polish finish on the work surface after you're done shaping it

[indian joe]

Could the extractor be forcing the base off center in the chamber?

maybe ---but gravity is at work too...............

[deces]

Plenty to pick from.

316701

[uscra112]

Worth knowing that those Lee expander stems appear to be nitrided, like their dies. Hard skin, but very very thin, and once you're through it the core machines like it was 12L14 or something similar. The carbide tooling I use anyway had no trouble with it, but HSS may.

[MostlyLeverGuns]

I use Hornady Unique on a Q-tip to lube inside of case before expanding, makes a significant difference on ease of expanding. With lube, I haven't had much trouble with slipping but I do break neck expansion into multiple smaller steps, and go slow with each expansion, giving the brass time to move.

[uscra112]

......I do break neck expansion into multiple smaller steps, and go slow with each expansion, giving the brass time to move.

My worst "case" was expanding .17 WSM to make .25 Stevens. Took four steps and two annealings. Did not use lube for fear of contaminating the primer compound. Imperial die wax on the expander taper might have helped, but I have no other use for it, so haven't bought any.

[RonnieMilsurp]

Could the extractor be forcing the base off center in the chamber?

Don't think so. It barely contacts it.

[RonnieMilsurp]

Plenty to pick from.

316701

Thanks!

[indian joe]

Just did 2 more from fresh cases. Put about 1/8" of tape next to the rim to fill out the space in the chamber. Upped the powder half a grain, pre-trimmed the case. Fired exactly vertical. Got the exact same results. I even re-cast the chamber to make sure I'm not crazy, and it looks normal. Straight walls, just like Mr Springfield intended.

I am putting 6 grains of Win 244 (don't have Trail Boss or any shotgun powder) and filling the rest pretty tightly with corn meal, then capping with wax. The only thing I can think of is that the powder is still settling to one side when I chamber it, even though there shouldn't be much room for things to shift. It's definitely always the top of the chamber that doesn't expand for the first inch. Then it blows out evenly for the last .75".

316674

If you use the tapered expanders you will get a much nicer result than those in the picture , plus save on primers and powder