How Much Sizing Is TOO Much Sizing? (UPDATE: I'm Stupid. Now a Case-Forming Thread)

[Warm_Garand]

UPDATE:

I mistakenly assumed that this brass was 7.5 French based on a faulty head stamp recollection.

Cartoucherie de Toulouse, Toulouse, France head stamp is TE, not TA.

I'll leave the post text intact, just in case somebody is interested.

Skip down to discuss forming 7.5 MAS from 7.5 Swiss.

UPDATE2:

The dies to convert 7.5 Swiss to 7.5 MAS do exist, but acquiring one doesn't make a lot of sense in my situation. It might be the just ticket for somebody, though.

Link to 50% off RCBS case-forming die:

http://www.midsouthshooterssupply.com/item.asp?sku=0004458199

ORIGINAL POST:



I scrounged up some French 7.5 (MAS) brass at the range––almost 200 cases––but upon closer inspection I'm guessing it all must have been fired in the chamber of a rifle with headspace issues.

This once-fired brass mics at 2.179 –– which is .053 longer than MAX.

The spec is .482 ––but it mics at .494

Unfired French Military Cartridge For Comparison:

PRVI Partizan:

How does that happen? Should I assume this brass was shot in a rifle with headspace issues?

The once-fired case beside 2 unfired cartridges (French mil and PRVI) Note the height of the shoulder.

Just to see if it would size I tried running it up into my sizing die––it took 3 or four attempts, but it finally sized (Imperial is the tits)––but afterward there was a distinct belt at the base, almost like it was a belted magnum.


After seeing the bulge at the base I tried running a once-fired case up into an RCBS Trim Die instead––and it did size full length in the RCBS Trim Die (insert case half way, extract case when resistance builds/serious resistance is felt, smear sizing die wax around, finish sizing case)––It sized well, there was no belt, but at the top of the sizing stroke I was astounded at how much brass there was to trim. The already long case had stretched even further––2.178 to 2.213 (!).

Picture above illustrates (L-R ) once-fired bad headspace brass, brass re-sized in RCBS Trim Die, and 2 virgin cartridges, 1 French military and 1 PRVI Partizan.



My question is: Is it safe to resize this brass in the trim die, trim it, then the FL sizing die, and then reload it––or am I asking for a case-head separation?

On the left is the original once-fired. On the right is the (untrimmed) brass after it has been sized in the trim die

I'm reluctant to scrap this brass, but I absolutely will if I should.

What do you think––will I be able to get away with all that sizing––or am I asking for trouble?

I'd appreciate any advice.






SPECS for 7.5 French MAS

MAX CASE LENGTH: 2.126
TRIM TO LENGTH: 2.116

THIS PARTICULAR ONCE_FIRED BRASS:

1X Fired Brass length: 2.178
1X Fired after sizing in RCBS trim die: 2.213 (!)

BASE MICS AT .496 vs, .486 SAAMI Spec.

 

[jasons]

I'd size them, load them on the light side, and inspect for stress signs after the first firing but I'm no expert.

 

[Jasper]

are you SURE they're once fired....out of the right gun?


it wouldn't be the first time someone fire formed brass for a wildcat

 

[EddieCoyle]

I bet someone fired it in a rifle with a different chambering. My guess is that it went though something chambered in 7.5x55 Swiss (look up the case dimensions and compare them to your fired brass).

It wouldn't be the first time that some knucklehead used an incorrect (but similarly named) cartridge in a foreign rifle.

I wouldn't load them, but if you feel comfortable touching off a badly stretched case a couple of inches from your eye, go for it.


ETA: And before someone chimes in to say that people fireform brass all the time without problems, let me point out that fireforming to reduce case taper and/or blow out and sharpen up the shoulder (like an Ackley-Improved cartridge) is fine. But In the photos above, the case head just above the web has been expanded by 0.016". That's a lot. I've never heard of fireforming where the case head gets expanded that much.

 

[Warm_Garand]

Interesting theory that they were fired in a Schmindt-Rubin. I've seen the rounds side by side, and they are quite similar in appearance (without a mic).

My BIL has one--I'm going to see if a round will chamber in his rifle.

 

[gerrycaruso]

From what I can find, the 7.5x55 Swiss has a case length of 2.189 and a base diameter of .496. If 7.5x54 brass is so difficult to get that you're tempted to use that stretched brass, you should probably get a broken shell extractor. It really sucks when you open the bolt and the front half of the case stays in the chamber.

 

[Warm_Garand]

Update: EddieCoyle's hunch about 7.5 Swiss was correct.

I researched the head stamp and this brass isn't MAS brass at all, it is actually 7.5 Swiss once-fired (D-OH!

):

Web Page With Headstamp Codes....

My mistake––I had seen a lot of '79 French Military brass for sale, and had ASSumed that T A was Toulouse Arsenal––but it isn't, it is a Swiss manufacturing headstamp.

So, OK––the physics of the situation are now completely reversed––this cartridge case hasn't been catastrophically STRESSED––and has instead been COMPRESSED to 7.5 MAS specs.

Is anybody fluent in case-forming? Have I accidentally (but like a tard) discovered a way resize 7.5 Swiss to 7.5 French with an RCBS Trim die and Imperial Sizing Wax?

I know that RCBS sells a 7.5 Swiss>7.5 MAS conversion die––but it's like $300.

MIDWAYUSA....

Do you think it is unsafe to shoot a cartridge formed in this way?

The cartridge case will be fully supported by the MAS chamber when fired)––so do you think it is OK to load this brass if I can get it sized and trimmed to fit in the MAS chamber?

As always, I would appreciate your input.

FINAL UPDATE:

Oh well--time to pull the plug on this particular experiment. I formed a handful of cases in the trim die, then gave them a FL resizing. The only problem area I encountered was the oversize band at the base. Some of the cases would chamber, but some wouldn't--so it makes no sense to proceed.

Per the update in the first post, the dies to form Swiss to MAS do exist, but it doesn't make a lot of sense for me to acquire a set, given that I don't have a lot or free/readily available 7.5 Swiss to form.

Oh well, it was an interesting experiment.

 

[Slowdive]

I bet someone fired it in a rifle with a different chambering. My guess is that it went though something chambered in 7.5x55 Swiss (look up the case dimensions and compare them to your fired brass).

It wouldn't be the first time that some knucklehead used an incorrect (but similarly named) cartridge in a foreign rifle.

I wouldn't load them, but if you feel comfortable touching off a badly stretched case a couple of inches from your eye, go for it.


ETA: And before someone chimes in to say that people fireform brass all the time without problems, let me point out that fireforming to reduce case taper and/or blow out and sharpen up the shoulder (like an Ackley-Improved cartridge) is fine. But In the photos above, the case head just above the web has been expanded by 0.016". That's a lot. I've never heard of fireforming where the case head gets expanded that much.

I agree with this entirely. What are you really saving and is it worth it? (Coming from a self proclaimed brass rat). Alarm bells are ringing!

 

[NavelOfficer]

Many reloaders here will swap/buy once-fired GP-11 brass. If you get no takers, I could probably do all of 8 cents each ($13 for 100 or + 8 cents each for whatever you can fit into a small box) shipped in the USPS Small Flat-Rate Priority box.
FWIW, I know of a shop in SW CT that has some of the MAS (light blue box) ammo as well as some Prvi and surplus fodder. It's not bargain priced, but it is there on the shelf.
Contact me if you want to grab it (I can work with Jay and probably get you a better price) and can have it for you in North Stonington, CT if that saves you some mileage (or pay for UPS shipping).

 

[Patriot]

It could be someone re-sized them for another caliber. I re-size 30-30 to .32 Win Spl. If you picked up one of the re-sized cases to reload in the original caliber it wouldn't do too well.