Gas blowing back in 8x57?

[Dhall_37]

Hey folks, I have a quite nice Mauser 98 guild rifle, sporting a mannlicher stock and double set triggers.

The stock had split and I repaired it and decided to try a cast bullet through it, however upon firing I was getting a whoosh of air or gas? Back into my face making shooting quite awkward.

My recipe was brand new PPU brass FL sized. 20gr of IMR 4227 a 180gr coated gas checked bullet seated a little short to ensure I didn’t cram the lands.

Cases came out sooty from about the neck half way down the case, only on one side however.

I believe I was getting gas back into my face because of the base of the cartridge not fire formed to my chamber quite yet. However I’ve shot this load in my straight pull M95M and had good results.

Any advice is welcome!

[Der Gebirgsjager]

I think you're correct. You need to "up" the load a bit to get a good seal in the chamber.

DG

[Winger Ed.]

Like so many military rifles-- The chamber might be a little on the 'generous' side of the specs.
I'd up the powder a little if you're not close to the max.
You might not be getting enough pressure for the case to expand and seal.

[Dhall_37]

I’ll UP the charge some more as advised fellas. Max charge is listed at 26gr for a 168gr pill.

[Randy Bohannon]

Anneal the case necks,bet all that will go away.

[FullTang]

Annealing does work like a charm, and it's good for the brass in many ways. It's pretty quick and easy to do a lot of brass in a few minutes with a cordless drill and a spark plug socket.

[Rich/WIS]

Other than dirty does the brass look okay otherwise. Depending when it was made many of the original rifles in 8X57 were rechambered after WWI to 8X60 since for a while it was illegal for Germans to own a rifle in the military caliber. Also possible it was a GI capture and after WWII 8X57 ammo was unavailable so may have been rechambered to 8X06.

[Dhall_37]

I’ll give annealing a go. I have a torch in the garage. It’s crude but will do the trick.

[Dhall_37]

Other than dirty does the brass look okay otherwise. Depending when it was made many of the original rifles in 8X57 were rechambered after WWI to 8X60 since for a while it was illegal for Germans to own a rifle in the military caliber. Also possible it was a GI capture and after WWII 8X57 ammo was unavailable so may have been rechambered to 8X06.

If it was in 8x60 wouldn’t my brass be fireformed now?

[Gtek]

I have went the other way of skinning cat with several needing to be sized. Anneal, flare neck to hard drag in chamber, seat medium to soft boolit to just kiss and 14 grs of 4227. Load, 45 degrees up angle and rattle then level to boom.

[beemer]

Not enough pressure to expand the case and seal. When I started loading the 8mm I used loads comparable to my 303 and 7.62 X 54, I got sooty cases and blow back. I crept up on the powder charge till it stopped. It is called expansion ratio, the bore was larger than the 30 cals. It needed more gas, more fuel makes more gas.

[brstevns]

Might also check bore size , might need to enlarge bullet diameter. This besides what everyone else has said.

[wilecoyote]

with all due respect, full or reduced loads, if in my Mauser, I would stay away from any former combloc brass as I've learned to stay away from SMI italian mil. brass for my .308/7.62nato rifles.

[yeahbub]

My experience with PPU bras is that it was pretty hard. I had the same problem years ago with sooty cases and annealing took care of the problem.

[MarkP]

I have a Rolling Block in 7 x 57 that does that with reduced pressure or even moderate loads. I annealed the necks and shoulders on (50) cases and fired formed them and just neck size about 1/2 of the neck for reduced loads. Cartridges look funny as there is a step in the neck ahead of the shoulder but it seals the gas with lower pressure loads.

[oso]

Always wear shooting glasses. Paul Mauser lost an eye after testing one of his rifles. That was a consideration in his later designs, but it can still happen. Glad you are OK.

[oconeedan]

Stupid question....is the straight pull M95 an 8x57? I thought they were a rimmed cartridge?
And my experience with PPU brass is it is very hard, compared to others.

[oconeedan]

Stupid question....is the straight pull M95 an 8x57? I thought they were a rimmed cartridge?
And my experience with PPU brass is it is very hard, compared to others.

[oconeedan]

For some reason it double posted.

[Texas by God]

The M95 Steyr does use an 8mm Rimmed cartridge, not the 8x57mm.

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[muskeg13]

The M95 Steyr does use an 8mm Rimmed cartridge, not the 8x57mm.

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Some 123,000 M95s were converted to regular rimless 7.92x57 Mauser. The conversion included replacing the sights and modifying the magazine to accept Mauser stripper clips, eliminating the En bloc set-up. http://www.hungariae.com/Mann95Se.htm

The vast majority of M95s were rebored and rechambered to 8x56R, which is .329-.330, and many of these more common conversions involved cutting WW1 long infantry rifles to carbine length.

[winston10]

None of the M-95's in 8x50mm were rebored at all when rechambered to the 8x56r . Same bore size, same barrel with same size land and groove .

[Dhall_37]

Thanks for the advice guys. I have some other projects going too. But soon I’m going to anneal and bump the charge up in a latter type deal and see if that’ll keep the gas blow by down.

I shoot reduced cast in my carcano with H4895 and have good results and not much blow back. I think It definitely just needs to be bumped up some. I’ve read that fast burning powders in larger cases can sometimes act funny if reduced too low.

[Dhall_37]

Stupid question....is the straight pull M95 an 8x57? I thought they were a rimmed cartridge?
And my experience with PPU brass is it is very hard, compared to others.

It’s a special M95 (M95M) converted to 8x57, a fixed mag, stripper clip guides and a Yugo Mauser barrel!