7x57 Mauser question / split brass

[Lefty Trigger]

Loaded these up last year with new Remington brass (no idea how old it is but was new) CCI 200 primer with 46.5 gr of reloder 19. Not hot by no means only producing 2430fps with 139gr SST bullet. Shot 20 rounds tonight and got these three with split necks! This brass is getting hard to find so I don't want to keep getting this. Any ideas??

 

[joshb]

Looks like you should anneal the rest. What size is your loaded brass and what size is your chamber neck? They look pretty splayed.

I bought some PPU a while ago. I kinda remember loaded factory was pretty cheap. Take a look.

 

[Fast14riot]

S&B ammo isn't expensive and their brass is excellent.

Related note, had some Remington 6Rem brass that was losing primer pockets on factory ammo, getting blow by, and split necks. Got rid of that brass.

 

[Uncle Ed]

If your 7mm Mauser is a surplus military rifle, it will have large chamber and neck dimensions. Meaning the neck will expand a great deal and it will be hard on brass. I would measure the fired neck diameter and see how much the neck is worked in sizing.

Also when Remington and Winchester lost the contract to produce ammunition at Lake City they both fell on hard times. And the quality control of both companies was not what it was in the past for their ammunition with Winchester being the worst.

Bottom line, get some Prvi Partazan brass, the quality of the brass is higher than most American brands. And judging from your photos it looks like your necks expanded a good deal like most milsurp rifles with their long fat chambers.

 

[Lefty Trigger]

Fired brass measures .323 and after resizing it measures .310. The rifle is pre-war military from Venezuela with 4 digit serial number. My dad sporterized it back in the late 50's for a hunting rifle. I don't get it out very often but it is fun to shoot.

 

[hoz53]

Fired brass measures .323 and after resizing it measures .310. The rifle is pre-war military from Venezuela with 4 digit serial number. My dad sporterized it back in the late 50's for a hunting rifle. I don't get it out very often but it is fun to shoot.

even though you bought the brass as new it could have been sitting around for years and it will get brittle just sitting there. Ive had it happen. Get some new prvi partisan likes been said. for my dads 8x57 im going to get some lapua

 

[Rsadams]

I had that same problem with some old .308 Remington brass my uncle had.... Never been reloaded I fired it right out of the factory box.... The next and first reload split the necks on a few..... Threw that box away and moved on to some newer Remington brass I had and the problems stopped.... It was almost like the brass had gotten hard sitting around.... Never had that problem with any brass since even Remington.... I have some newer Remington with about 5 reloads and still going and I don't anneal... Had me scratching my head also....

Edit... Hoz beat me to it....

 

[DGP4]

I would agree with annealing the remaining lot which is pretty easy to do. It has been my experience that some lots of Remington and Winchester brass are often not annealed properly at the factory and result in split necks. I buy PPU 139gr ammo and use their cases. It is excellent brass and the PPU ammo shoots very well in my 1895 Chilean Mauser. I believe that some reloading supply shops sell PPU brass for reloading.

 

[CaptainMal]

Fired brass measures .323 and after resizing it measures .310. The rifle is pre-war military from Venezuela with 4 digit serial number. My dad sporterized it back in the late 50's for a hunting rifle. I don't get it out very often but it is fun to shoot.

Resizing the necks .013" seems very excessive to me.

There are a variety of solutions as you deal with neck tension, brass thickness, die dimensions, chamber dimensions etc. That much neck resizing just seems out of line.

 

[Ares]

RWS makes top quality 7x57 brass that is tough. Not that hard to come by either

 

[Jeffrey Tooker]

Fired brass measures .323 and after resizing it measures .310. The rifle is pre-war military from Venezuela with 4 digit serial number. My dad sporterized it back in the late 50's for a hunting rifle. I don't get it out very often but it is fun to shoot.

Remember old military 7 X 57's, i.e. 1908 Brazilian Mausers
have a .286 bore not .284 which is now the standard.

Jeffrey

 

[hoz53]

Resizing the necks .013" seems very excessive to me.

There are a variety of solutions as you deal with neck tension, brass thickness, die dimensions, chamber dimensions etc. That much neck resizing just seems out of line.

An old thread but yeah me to. I’ve got a Chilean Mauser in 7x57 I need to check neck expansion. Mite have to get a bushing die or a reamed out Forster.

 

[hoz53]

RWS makes top quality 7x57 brass that is tough. Not that hard to come by either

Not cheap either

 

[Lefty Trigger]

This thread kinda died for awhile but I'll check back in and say that after I annealed my brass the issue of split necks went away. Also I had a friend give me some PPU brass and I would never buy that that stuff, ever. Shooting free stuff is ok but I'm leaving it behind for the brass scroungers. Absolute crap, necks not on center, mal-formed shoulders, primer pocket holes that looked like they was punched by hand. Sorry but I'm going to stick with name brand brass.

 

[MagnumManiac]

I’m having the exact same issue in my new 264WM, brass is at least 10 years old, annealed prior to sizing and has been sitting all this time. Every one has split on the first firing, but not a full split to the case mouth.
It looks work hardened to me, or maybe age fatigue.
Anyway, I’m not happy that this WW-Super brass has done this, as 264WM brass is unobtainium here in Australia.

I am going to anneal again, I think that’s what you’ll need to do too.

Cheers.

 

[ebb]

I have always heard that RWS brass is even tougher than Lapua brass. I found a thread at 24 hour campfire about 7x57 and the guy had a modern gun with a tight chamber and had problems with the RWS being too big for a tight chamber. Sounds to me like it was made big for problems like yours, a loose military's rifle chamber and a slightly over sized super tough brass to go in it. I bet 150 or 200 would last you till ???

 

[rogn]

Almost all 7x57 chambrs had / has excessively large necks as some kind of remembrance of military needs. Sort of need to have chamber and necks big enough to chamber a round dipped in mud or horse dung. Even Saami seems to run amuck. Any brass that sits too long seems to age harden, how much due to age or how much due to the toxic stuff we clean or flavor our houses with. Annealing will aleviate most of this splitting. Another course of action is what I did years ago for target shooting with my 7, make yur brass out of longer brass, like -any -06 derivative . Then just trim and turn to fit. Forster has the most economic way to trim and turn brass. Bear in mind though that their turner is not competition grade, but its good for hunting ammo.
RWS brass if I recall is based more of the european 57mm brass which seems to be a 0.00? or 2 bigger at the head end. My 6x47l brass will not fit my Remi URBR chambers.
But PPU is the simplist cheapest answer. Only fly left in the ointment is the FL dies are over small in the necks and over work brass in the necks. But almost all FL dies have that issue.