I have 3 MK V's in .257 Wby and a Ruger #1 rebarrelled in .257 Wby and they shoot everthing well...if the powder is slow enough.
How far are you shooting?
RL 22, RL 25, H1000 and IMR 7828 have all worked well for me. I usually use 115-120 gr bullets (whatever is on sale since the rifles like them all) because I have lots of them around but wouldn't think anything of using 100 gr bullets on deer.
If you're not needing to shoot long range with it, shoot a 117 Hornady round nose, it's a guaranteed DRT load. WIth RL22, I'm able to get about 3400 at the muzzle. Only downsize is the horrible BC.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JCH</div><div class="ubbcode-body">i would guess that R22 and 100 Barnes TSX's are a good start.</div></div>
Couldn't see myself going any farther than that, either...
Another buck taken by one of my hunters with the same rifle and load.....I've loaned that rifle out a time or two....maybe the "perfect" open country deer rifle ever.
Magnum Research Mountain Eagle(Sako Action) same specs as a Rem 700 (no dovetail)
26" #6 Lilja bbl. 1-10"
10X42 S&B PMII
Badger 20 moa rail
Nightforce rings (30mm)
80gr TTSX @ 3700fps. They can be pushed faster, but that's what shoots best in my rifle. Groups like this:
My first pronghorn. Shot it with the above load at about 275 yards. DRT. Left about a 2" exit wound.
My buddy shot this one with my rifle and same load. Antelope was running hard and hit too far back on first shot, but the bullet exited high in the right rear hip. Exit wound was BIG, but don't have a picture of that one. Stopped the buck immediately though. This was the finishing shot:
My buddy and I just returned from Wyoming where we both took nice mule deer using the 257 Wby. Handload was 100g TSX and RL22, both deer one shot, DRT.