Trouble Loading for a 257 Wheatherby

[fishingstockwell]

Thanks to everyone for all the responses. Your information has certainly helped me rethink what to try next with this project. Norma's load data shows 69.0-72.4 grains of MRP for the 100 gr Nosler Ballistic Tip and 66.0-69.8 for a 117 gr Hornady round nose bullet. I'm going to pick up a pound of MRP and try loading the Accubond 110 with about 68.0-70.0 grains with the Weatherby factory seating depth provided by MudRunner. I don't know how temperature stable MRP is, but RL 22 is well know for wide velocity swings with temp changes. I have had great luck loading very accurate loads with RL 22, but I live near Sacramento, CA and load development during the summer is done around 90 degrees. I've been reluctant to use it for my hunting loads because we typically hunt the other western states and average temperatures are roughly 50 degrees, or more, lower. I have heard that RL 23 is a very temperature stable powder, with an almost identical burn rate to 22, but alliant shows no load data for the 257 Wby. I might give them a call to see if there is a conversion for 22 to 23, and give that a try as well. Thanks again for all the suggestions.

Matt

 

[cacsrx1]

115 Bergers and H1000 gives me great results.

 

[okie man]

Get you some 7828 , start your charge weight at 66.5 and work up in half grain increments.seat your bullet so the base is right at the bottom of neck. You'll find a node somewhere between 66.5 and 69 grains! I've used 5 different bullets in my 257 way and all are moa using this method!

 

[220s]

Not much experience with Wby's mine is limited to the 240 I have.
Load development was virtually no existent. Factory 100gr loads were shooting around moa so initial development was with light weight pills 55/58gr for a varmint preditor load.
Being so short OAL was dictated by how much projectile I was happy with in the neck. Loaded a couple of different brands from listed starting loads to a few grains below listed max. Rifle showed a decided preference for one projectile with groups half the size of the other brand.
Loaded up some more of the preferred brand from where we had stopped up to the listed max, accuracy continued to improve as velocity increased.

As much as your set on a particular projectile it might pay to try another brand. I've had quite a few rifles that for what ever reason just refuse to shoot particular projectile well but the same weight and style from another maker exceptionally.
My 240 and all the swifts Ive owned seem to shot best when run at full speed or close to it.

 

[Nitro 375]

My Vanguard in .257 Weatherby was a bit of a pain but I enjoyed the challenge. Some rifles need a little help, some a lot and others just run from the git-go. First thing to go was the injection molded stock. I bought the rifle at one hell of a price and intended to get a "real" stock in the future. Stocky's stocks had a sale like they do from time to time and that little problem was taken care of. Mine will shoot 120 grain Partitions into a 3 shot group at 447 yards that you can cover with a U.S. quarter if the monkey [me] behind it pays attention. At 100 yards its just a ragged hole. Keep an open mind about bullets and powders and experiment. This is no target rifle just a hunting rig but I enjoy it very much. My cousin teases me for using "outdated" bullets but things seem to die rather quickly when pierced with one. PM me and I will share data when I get home tonight if you like. IMR 7828 was the winner for me, Norma MRP was pretty good too.

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