7x57 Load Development

[RStien321]

I have been working up handholds for my 7x57 Mauser (barrel is 1:8 twist), and found I really struggle with the 160g A Frame and 175 Partition development.

The gun shoots lights out with 143g Hammer Hunters and 139g Hornady Spire Points with near zero load development.

I’ve shot north of 100 partitions with different powders, seating depths, etc. 30 Swift A Frames (those are like gold right now) and sometimes I can get a 3 shot group in the 1.5” range, but then the same load will open up to 4” on the other side of the target. Incredibly frustrating.

Just looking for advice/suggestions if this is a common problem folks have run into? I have had a lot of luck with terminal performance of the 143 Hammer in my 28 Nosler at 500 yards on elk and mule deer, which should be similar impact velocities that the 7x57 would have at 150 yards in Africa.

 

[1r4rc]

Twist is plenty quick for the heavier bullets. Would have guessed the problem just the other way around. Throat may be set up for 140s. If you are getting good SD, play w depth... but it may be easier to just use what it likes (or take another rifle).

 

[Elkeater]

I use the 140 class hammers out of my 7-08ai (not exactly the same thing but not too far off either) and I would not hesitate to use that bullet in Africa. I’d rock the hammers and call it good. Plus it seems hammers are always available.

 

[RStien321]

I use the 140 class hammers out of my 7-08ai (not exactly the same thing but not too far off either) and I would not hesitate to use that bullet in Africa. I’d rock the hammers and call it good. Plus it seems hammers are always available.

Okay - that was my initial thought too. Just getting in my head a bit as the date of the hunt gets closer and closer.

I've had really good luck with Hammers on North America game. It's more that in my head pairing the 7x57 with a more "traditional" premium bullet was what I wanted to work. But ultimately what is more important is a super consistent, accurate, and reliable rifle. And that's what I am getting with the Hammers.

 

[AckleyHunter]

Maybe try a different powder. I tend to use slower powders with the heavier bullets. Something in the 4350 to 4831 range.

 

[RStien321]

Maybe try a different powder. I tend to use slower powders with the heavier bullets. Something in the 4350 to 4831 range.

I may revisit the 175 grain with IMR4350. I used IMR4350 with the A Frame and Hammer, but used N165 and RL19 for the 175 Partition.

 

[FlyGuy]

If the Hammer shoots well, use it.
The heavier bullets like the 4350 type powders.
Had excellent results with the 160gr AB and VV N550