257 Wby - N570

[RL338]

Getting loads ready for this spring for the 257 Wby. Got some correct headstamped Peterson brass to work with. I picked 4 bullets that Weatherby offered in their factory loads. 110gr ELD-X , 110gr AB , 115gr Bt , and 120gr PT.
I found 77grs of N570 fills the case full , was a little disappointed by this. The 110gr AB seemed to hit pressure earlier than expected. The 115gr BT and 120gr PT ran out of room. The 110gr ELD-X was the only one to reach the factory velocity before running out of room.
The Weatherby factory velocity is above the bullet description.
I have groups of each ready for some paper.

 

[JD338]

Good selection of bullets to wring out too accuracy. Looking forward to seeing your results come spring.

JD338

 

[phil]

Getting loads ready for this spring for the 257 Wby. Got some correct headstamped Peterson brass to work with. I picked 4 bullets that Weatherby offered in their factory loads. 110gr ELD-X , 110gr AB , 115gr Bt , and 120gr PT.
I found 77grs of N570 fills the case full , was a little disappointed by this. The 110gr AB seemed to hit pressure earlier than expected. The 115gr BT and 120gr PT ran out of room. The 110gr ELD-X was the only one to reach the factory velocity before running out of room.
The Weatherby factory velocity is above the bullet description.
I have groups of each ready for some paper.
View attachment 28549View attachment 28550

N565 might be a better burn rate for those bullet sizes.?
I’ve done limited testing with a 25 Sherman Mega, 82-83gr capacity, it performed well with R23 with 100gr TTSX and 116gr apex gen 3 monos. N560 would sizzle, but it’s not temp stable.
Peterson brass is thick, definitely holds less than most, but man it’s been great for durability and consistency. Did you try a drop tube or vibration with the n570 ?

 

[RL338]

I was using 5” drop tube. This brass on the scale is 5grs lighter than the necked down Peterson 270 Wby brass I’ve been using for several years.
I know if want more velocity WC867 I have will do it at the expense it runs a little dirty in this rifle.
For now I’m doing this little sample run of bullets too see if they work in this rifle. I’ve got a great load with 100gr TTSX and 120gr HP on hand.