Reloading .257wby mag = load data =

C

clegger

BANNED
BANNED
BANNED
EE Expired
Rating - 90.9%
10   1   0
So I gave reloading the .257wby mag a try...

First batch was reloaded to these specs based on factory ammo specs;

Nolser brass
nolser partition 120g
WLMR
H4831
3.18" OAL

The first powder charge I changed in .5g increments in a group of 5, I started at

64.5
65
65.5
66
66.5

Turns out the wby mag like a full case and the 66.5 was the most accurate, unfortunately the smallest group I got was 2.75" at 100m, so I decided it was probably the oal that was messing things up so I tried this combo;

nolser brass
Nolser partitions 120g
WLMR
H4831 66.5g

I started with a OAL of 3.24 and worked my way out, knowing that my freebore was well over .3" I wasn't worried about hitting the lands;

3.24
3.25
3.26
3.28
3.30

3.25 gave the best group at .7" at 100m

So my final recipe is

Nolser brass
Nolser partition 120g
WLMR
H4831 66.5g
OAL 3.25"

As for velocity the book has it somewhere in the 3400fps zone. I was worried about accuracy and don't really give a hoot bout how fast she goes, I know it's faster then what I can throw. I'm happy with .7" and fine tune in the future but for now I'm working on building up around 100 rounds for hunting and practice.
 
What firearm are you using.........make and model? If it is a Mark V, seat the bullets as long as you can that they can fit inside the magazine well. Second, you must try at least two more powders, such as: Reloder 25 and IMR4831 which my 257's enjoyed. Your Nosler Partition is a great bullet for hunting and it will love one or two particular powders.......give it a try and good luck.
 
clegger said:
It's out of a Wearherby vanguard deluxe 24"
Click to expand...
I have never used the Vanguard, however will assume that it has .378" of free bore, therefore as stated, seat them as long as you can in the magazine well and try two or three different powders, reloader 19 is another great powder........stay with the same bullet. Don't torque the grip or trigger finger, squeeze it straight back once you are rock steady on the bench. With our 257 and 270 Weatherby's we get 3.395" COL.
 
Id love to try one or too different powders, but I can't find anything in my area. I mean NOTHING!! When it comes to accuracy I don't know if I really need anymore then a .7" group, as a deer/elk vitals are much bigger then that.

I'm still going to try more powder as it becomes available and hopefully see how small I can get my groups, but I'm very happy as is.
 
Hmmm....

I'll give this whole "seat as far as the mag will allow" a try, and post the results. Right now I'm sticking to the book max of 3.25"
 
You must log in or register to reply here.
Back
Top Bottom