8mm mauser load help

[Springfield_1911SS]

I just made my first 20 8mm mauser rounds I used new winchester brass, hornady 170gr bullets, and winchester LR primers. I used IMR 4064 for powder. I used the load data from My lyman relaoders handbook i used the starting charge of 43.5 grains. It lists a max of like 48 grains. I looked at a few other load books they put the staring charge of IMR4064 closer to 35 grains. Should they be ok or should I pull them and reduce the charge? Any body else use this powder/bullet combo?

 

[davidjblythe]

I have used winchester brass with the 170 gr round nose hornadys before. However I've used CCI primers with either Varget or IMR4895.

According to Hornady's manual:
IMR4064's max load (2600 fps) for the #3235 170gr round nose is: 49.4 gr.
The lowest load listed is (2200 fps): 41.1 gr.
COL: 2.890

Please keep in mind that several manuals will reduce the 8mm load down very far to keep shooters from blowing up their firearms when they try to but an 'IS' (.323) round down the much smaller bore of the older mausers.

I quadruple checked the numbers I wrote down, but search the internet and find other reloading sites that show max loads for this combo.

Since this came from the latest hornady manual, and you're using hornady's bullets, I don't think there's any reason not to trust their numbers.

 

[BsChoy]

I thought I was overloading too in my German 8x57. I routinely use 47.0 grains of IMR4064 in mine. No pressure issues but this is with 150 hornady bullets. I would suggest starting at 42.0 and going up in .5 grain increments

 

[xsquidgator]

I only have 150 .323" SP bullets, so not quite the same thing, but...
My Speer #13 listed 56 grains of IMR4064 as the max for 150SPs. I worked up to it and didn't have any issues with 56 grains of IMR4064.

I don't have my book but I'm sure you can work higher than what you listed for 170 grain bullets. My Speer guide says that 8mm Mauser in the US is usually downloaded more to the power of maybe a 30-30, but when loaded full house as it is normally done in Europe that an 8mm Mauser is roughly equiv. to 30-06. Fwiw my Lee #2 guide had significantly lower charges listed IIRC for the same load, I cautiously worked up to the Speer guide numbers after reading what Speer had to say about it.

 

[cracked butt]

FWIW, my accuracy load with 8mms is the 170 hornadyRN, Federal 210 primer, remington brass, and 50 gr IMR 4064. I've gone up to 51 grains in a persian 98/29, but the accuracy started deteriorating after 50gr. It shoots very good in all of my 8mms. This load was listed as a maximum load in an older hornady manual, just be safe and work up to it.

I would start at 47gr and work up in .5gr increments. The mausers tend to have funny harmonics, you'll get really awful groups with some loads then move up .5 gr and the groups tighten up, when you hit the sweet spot you'll know it.


Re: groove diameters: The groove diamters as I've slugged them ranged from .3235" in a Yugo M48 up to .326" in a 98/29, with most of the rifles slugging right around .325." These were all rifles chambered in the 7.92x57JS cartridge and not the earlier cartridge.

 

[rcmodel]

What edition of Lyman book do you have?

Lyman #47 shows 8mm with 170 grain jacketed bullet & IMR-4064 powder:
Starting = 46.0
Max = 51.0 (Compressed charge)

Lyman #45 also shows:
46.0 & 51.0c.


rcmodel

 

[Springfield_1911SS]

i have 48th ed

 

[Steve C]

Speer 13 lists 45.0 grs as the start load using IMR4064 and 49.0 as the maximum with their 170gr Spitzer .323" dia bullet. If you are shooting in a Mauser 98 your 43.5gr load should be fine as a start load with plenty of room to grow the charge.

 

[Eljay]

As a side note to loading 8MM I form cases from 30-06, I saw it in an Shooting Times article by Lane Simpson, there are also some loads listed if I can find it I will report back. I have some 8MM brass, but forming them from some thing very common was a real kick.

 

[Clark]

Hornady says 49.4 gr IMR4064 170 gr RN 2.89" OAL and says 2900 fps for a 24" barrel.

Quickload thinks that should be 2698 fps 48,104 psi.

What? Hornady published a wimpy load with that is really 200fps slower

SAAMI registration of the 8x57j .318" 1888 Mauser is 35,000 psi
SAAMI registration of the 8x57s .323" 1898 Mauser is 35,000 psi
CIP registration of the 8x57s .323" 1898 Mauser is 56,564 psi


http://en.wikipedia.org/wiki/7,92_x_57_mm

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

In my humble opinion, the 98 Mauser is a much safer platform for the Mauser case head used in the .270 cartridge design than many modern sporting arms commercially chambered in the 65,000 psi .270.

I don't think that the registration of a Mauser case head at 65,000 psi in the .270 was a good idea for mass produced ammo in millions of different guns, and that may be why new registrations of the Mauser case head in 260 Rem are at 62,000 psi.
I do feel that the individual handloader can load his .270 to 65,000 psi and get useful safety margin without fear of sticky bolt or loose primer pockets on the first usage.

If I were putting IMR4064 in a 98 Mauser behind a 170 gr Hornady, I would take 65,000 psi as the upper limit. That would be around 54.5 gr IMR4064, 65,000 psi, 2954 fps 24" barrel. But that would be 106.8% powder fill, and it may not fit.
51 gr is 99.9% powder fill and that will likely fit. It would be 52,827 psi, 2779 fps.
And that pressure would be kosher in Europe, where the rifle was likely made.