Problems reloading 8mm Mauser with converted brass

[lorne19]

Hi everyone,

I've just begun to experiment with brass conversions and my first attempt has been to convert 30-06 to 8mm Mauser. My problem has come from the primers backing out of the case when fired. Initially I thought that due to the shoulder not having been properly fire formed yet that I was having head space issues and this was the cause. This has proven to not be the case though, my five test cases all exhibit the same problem ever after having been fire formed and reloaded and fired again. Any thought on why this is? My test loads were 44g of IMR 3031 and 46g of IMR 4895, used just to test the brass.

Thanks

Lorne jr

 

[deagle2008]

i used to convert 30-06 to 8mm too but never had that issue. maybe over pressure or head space is the issue here. try backing down from 44g powder.i use IMR 4895 its great

 

[lorne19]

Head space was my first thought but I've tried my test rounds in 2 different rifles with the same results. I also don't see how 46g IMR could cause high pressure, its a middle of the road load according to my manual. Also normally aren't backed out primers a sign of low pressure?

 

[deagle2008]

yes you are right low pressure does that. so try putting more powder in there

 

[Receipt]

Factory 8x57 does this to me. Hotter handloading solved issue. Factory velocities and recoil are significantly more mild.

 

[ciphery]

Did you aneal the front 1/4 of the case before fire forming? Perhaps hard brass has preveted proper fire forming

 

[lorne19]

Yes all cases were annealed after sizing. The consensus so far seems to be that my test load was too light. Does anyone load 8mm with IMR 3031, 4064, 4895 and can recommend a more suitable test load?

 

[MRP]

006 bras loaded 50gr of 4064 with a 150. no probs.

 

[Tinman204]

I've never encountered this problem and pretty much all my 8x57 is either 06 or 270 brass.

That being said, this condition is usually headspace issues, too light of a charge or dies that are setting the shoulder back too far.

I can't give load recommendation til you mention the bullet weight and rifle just to be on the safe side.

I'm shooting 44-46 grains of 4895 I'm my turk mauser with no signs of pressure issues.

One thing I will mention is that 4895 seems to dislike the cold when I shoot it in the winter with mild loads. Often I switch to magnum primers or bump up the charge in winter.

 

[Eagleye]

Your loads are too light, as has been pointed out.

I would stuff at least 2 more grains of powder in there and see if that does not solve your issue.

The 8x57 is loaded to potential in Europe, but here the loads are very "soft".
Your loads are also quite "soft" IMHO.

Regards, Dave.

 

[gewehr76]

put more powder, issue will go away. If its an issue, who cares if fired primers stick out. Not a big deal as long as you hit the target its all that counts.

 

[bearhunter]

When I fire form new cases I look up the starting load in the book, add a couple of grains and load up. I also use the lightest bullets available. If the shoulder of the case is set back a bit to far during the swaging process you will have head space issues that will result in backed out primers with low pressure loads.

I had a similar issue with some 338-06 cases last fall. My 338-06 chamber reamer is designed to specifically have a single caliber neck and have a 225gr Hornady IL flat base spire point seated to the base of the neck and be five thousandths of an inch off the leade.

I sized the cases on a different press than I had the forming die set for. This resulted in a pushed back shoulder and excess headspace. About one in three primers were not being ignited. Not something that is desirable.

There is an easy fix though. Go to the closest store that carries appropriate size rubber bands and buy a package of the small diameter type that fit snugly over the neck of the cartridge case. This gets pushed back onto the shoulder when you chamber the cartridge and actually helps to center the case in the chamber. Now, the head of the cartridge is tight against the bolt face. No more misfires or primers backing out and a properly fitting case. Usually the remnants of the elastic band just disappear. That doesn't stop me from checking to make sure.

By the way, I am not a believer in using fillers over the powder to fire form cases. Usually just a waste of time/powder/primers.

 

[lorne19]

Thanks everyone for the input. In my case I'm loading 150g Hornady SP's and have fired my test rounds thru a k98 and turk with the same issue persisting with both rifles. I will try the advice given here and try a heavier load and keep my fingers crossed.

Thanks

 

[HIGHRPM]

I have run 47.5 grains of IMR4895 pushing a 150 grain Sierra soft point with a Winchester large rifle primer, with no issues at all.

 

[deagle2008]

Since the yugo rounds are dud and corrosive I pull them bullets and powder and reuse them in a new brass and primer works very well. Bullets range from 198 to 200 grain and powder is around 47grains

 

[brickman]

Light loads cause that problem. I see this with factory loads in 8mm.

 

[kawicrash]

Does anybody around you sell Prvi Partizan ammo? They are loaded to European specs, and I really like their brass. One box for experementing would be cheap enough.

 

[Brutus]

I often load 49 grains of IMR 4064 under a 170.

Fired cases appear normal to me.

 

[kjohn]

Since the yugo rounds are dud and corrosive I pull them bullets and powder and reuse them in a new brass and primer works very well. Bullets range from 198 to 200 grain and powder is around 47grains

That's what I do with some of the more ugly looking surplus. I use store bought 8mm brass, though, I did the "conversion" thing 30 years ago and found it to be a waste of time. I have enough 8mm new brass to last me for through the revolution.