I was looking in my old Lyman handbook for a 175gr load using IMR4320.
It lists 38grs at 2341fps and a max load of 42grs at 2583fps.
Accuracy load in this manual is 41.1grs of IMR4320 at 2506fps and a factory duplication load of 41.2grs of the same powder at 2538fps.

So, I started a ladder of loads between 38 and 40grs.

Then, I went over to the Hodgdon site which lists the starting load of 34.0grs at 2103fps at 39,100 CUP
and a max load of 36.2grs at 2213fps and 44,900 CUP (!!)

I've always done well using the my old Lyman book so what would one do in this situation?

Old gun/ new gun?

If I was shooting a modern firearm or a M98 Mauser I'd go with the Lyman. I've used the 1972 edition since it was printed and never had issue with a half dozen calibers. The Hodgden data may be good for SR Mausers.

I'm loading for this:

http://forums.accuratereloadin...1019521/m/5041043172

It is a small ring Mauser.
If I were smart, I'd measure the twist and see what I can determine form that - 175s may be too heavy in the end but I like to dial in a heavy first if at all possible.

Over the years I have noticed that my old Lyman manual (number 45 copyright 1970) is pretty 'enthusiastic' with IMR 4320 loads, at least the majority of the data in there that do not show pressure data. Not just for 7x57 either. After trying some of those loads and running into obvious pressure signs I stopped using 4320.

I got the feeling that they thought 4320, perhaps being numbered so like 4350, was a slower powder that it actually is.

Just my 2-cent take on 4320 as listed in old Lyman manuals.

Also note that in the Lyman manual number 45, their 7x57 loads were developed using a '95 Mauser with a 29" barrel and a .2865" (sic) groove diameter.

The 45th Edition is exactly what I have too!

So then, I think I'll keep these as the top end and ladder loads up from 34 to the 38gr ones I have and see what speeds and pressure signs I get on the way up.

A few months ago, I read that IMR 4320 has been discontinued. Keep that in mind before you invest a lot of time in working up loads.

If it were my small ring 7X57 I think I would try a bit slower stuff (if possible) for the 175 grainers. I have the 41st Lyman manual and it shows starting loads @ 36 grs/2255 fs.

Old caliber, old powder. My guess is the Hodgdon data was developed before they acquired IMR, so in the interest of selling their powder it may be a bit conservative. But having a small ring action that might not be a bad thing.

I like W-760 in the 7X57.

Good advice from you both.

I do have other powders to try.

As an excellent hunting load I used 45.0grs IMR4320 with the Speer 145gr SP bullet in my 24" barreled BSA Hunter rifle. This load was very accurate with a chronographed MV of 2864fps average. It was a consistent load and the 4320 powder performed without any pressure issues at that level.

I tried some 175gr Winchester factory ammo in the 7x57 and found it a 'slow' killer on the few red deer I shot with it. The 145gr Speer was by far a better proposition for red deer, chamois and tahr.
Bullets up round that 2800fps MV mark exhibit much greater shock effect, killing game quicker than the old slow moving 175 grainers in the smaller 7mm cartridges. Not sure why anyone would use them these days other than of course if you happen to have a stash of them.

After many moons shooting good 7x57 Mausers and Winchester and my latest, a Ruger 77 Reiner special I tried every known powder and settled on H414 for every weight bullet from 48 to 53 grs depending on bullet weight..got best velocity and accuracy followed by RL-19 second best..