JCK
Single-Sixer
First, we need to know if it's a tang-safety or a MkII.
Some of the early models had barrel issues. These need rebarreling to fix.
My MkII was very finicky! It shot well with loads that my very accurate custom Mauser w/ERShaw barrel gagged on.
Particularly, a 100gr bullet over 38.0gr of IMR3031. My Mauser was indifferent on it shooting 1.25-1.5" groups. It'll typically shoot 3/4" 5-shot groups with a 100gr Sierra over 45.0gr of IMR4350.
The Ruger shot the 3031 load to 1.25" which was its best. It also liked a Hornady 117gr RN over 42.0 gr of IMR4350. I shot several deer with it. My favorite load was 45.0gr of IMR4831 under a Berger 115gr Hunting VLD.
I seated this to touch the rifling and got 3,000fps. Not even a +P load!
It is the best DRT deer load I've ever shot! Even heart lung shots are DRT due to internal devastation.
Unfortunately not a lot of different factory loads are available for the .257Roberts and most are loaded to a max OAL of 2.725". I seated to 2.875" for my MKII. MY 98 Mauser has the so-called 3"chamber. I seat it to 2.995" OAL (Sierra and Nosler bullets).
Good luck! BTW, my rifles wear Leupold scopes...
Some of the early models had barrel issues. These need rebarreling to fix.
My MkII was very finicky! It shot well with loads that my very accurate custom Mauser w/ERShaw barrel gagged on.
Particularly, a 100gr bullet over 38.0gr of IMR3031. My Mauser was indifferent on it shooting 1.25-1.5" groups. It'll typically shoot 3/4" 5-shot groups with a 100gr Sierra over 45.0gr of IMR4350.
The Ruger shot the 3031 load to 1.25" which was its best. It also liked a Hornady 117gr RN over 42.0 gr of IMR4350. I shot several deer with it. My favorite load was 45.0gr of IMR4831 under a Berger 115gr Hunting VLD.
I seated this to touch the rifling and got 3,000fps. Not even a +P load!
It is the best DRT deer load I've ever shot! Even heart lung shots are DRT due to internal devastation.
Unfortunately not a lot of different factory loads are available for the .257Roberts and most are loaded to a max OAL of 2.725". I seated to 2.875" for my MKII. MY 98 Mauser has the so-called 3"chamber. I seat it to 2.995" OAL (Sierra and Nosler bullets).
Good luck! BTW, my rifles wear Leupold scopes...