257 Roberts Improved

O

OldSwede

New member
My brother-in-law asked me to go over his deer rifle, a Ruger 77 in .257 Roberts, because it has not been shooting well for him. I have found and corrected several of the usual problems (barrel touching wood, crown nicked, filthy action and barrel) and have done some "touch-up refinishing" on the wood and blue.

In looking at the rifle, I note that it is NOT a standard .257 Bob, but an "Improved" version. (I assume the 28 degree version, not the 40 degree Ackley).

Does anyone have some good loads for this rifle? I have access to a set of Improved dies and would like to load up some rounds for him so that he doesn't have to always shoot factory rounds in it (which he has been doing for the last, oh, 25 years....)

Thanks!
 
When ever you start working up loads for one of these AI's, I use the standard published loads for the standard chambering. Work up from there. Use the standard load development. Better safe than sorry.
 
I have confirmed that the .257 in question is an "Improved" and not an "Ackley Improved" model. Apparently litle is known about this cartridge.
 
The .257 Roberts Improved

By Chuck Hawks



The two most popular "Improved" .257 Roberts cartridges are the Ackley and RCBS versions. They are quite similar except for the shoulder angle, which is 40 degrees for the Ackley version and 28 degrees for the RCBS version.

The Hornady Handbook and Nosler Reloading Guide show maximum reloads for the .257 Improved (either version) achieving muzzle velocities (MV) of about 3600 fps with a 75 grain bullet, 3400-3500 fps with an 85-87 grain bullet, 3200 fps with a 100 grain bullet, 2900-3000 fps with a 115-117 grain bullet, and 2900 fps with a 120 grain bullet.

The Hornady Handbook and Nosler Reloading Guide show maximum reloads for the .257 Improved (either version) achieving muzzle velocities (MV) of about 3600 fps with a 75 grain bullet, 3400-3500 fps with an 85-87 grain bullet, 3200 fps with a 100 grain bullet, 2900-3000 fps with a 115-117 grain bullet, and 2900 fps with a 120 grain bullet.
 
Easy enough to look at a fired case and tell if it's 28 or 40* version. My 28" barrel fireforms using 87TNT's at 3650. With formed brass the load is an 85BT at 3775.....Win.760/9-1/2primer/WW brass, tightneck chamber, 0 freebore.
 
The Std Bob is a Great Cartridge and the improved version is a blast.

I have both Std and the Imp 40*. H4350 with 100gr NBTS kick serious whitetail butt... Always get a bang flop on the coyotes too..

As previously stated, start with the std bob loads and go from there. I have 3 Ack Imp chambered rifles and when first starting load development, I typically start my baseline at appx 90% of listed max std load. This approach has worked well for me in my rifles.

Nodak
 
I have a 40* version build by Mike Bryant and I can say the 115's run about 3000 FPS and 100 grain Nosler BT run 3150 FPS.

Excellant cartridge, but I did almost the same thing by wildcatting the 6.5 x 47 Lapua necked it down to 257" and gave it a 40 degree shoulder. That added about 2 grains of water capacity to it and I expect to run the 100's at about 3050 FPS, all the while using lots less powder.

ML
 
I obtained a Remington last spring and after using the most recent Nosler manual and 150 or so rounds of experimentation, I have found that H-4831 and a Sierra 87 grain came in around 1/2 inch with my very "unbenchrest" like shooting conditions, and the 100 grain Speer gave similar results with IMR-4350. The small amount of 300 yard practice I have done gave me sub-2 inch groups with the Sierra/H-4831 combo.
Interestingly, one surprise was the fire-forming produced 1 inch groups with 100 grain, WW+P Silvertips. Good enough for east of the Mississipi coyotes.

Good luck.
 
I headspaced my 257RAI 40 degree with a standard 257R headspace.
That is a mistake, and should be .004" shorter for shoulder - neck joint ring crush.

As a result I have to do an extra step of case forming with cream of wheat and 10 gr of pistol powder.

By the time I have prepped and formed brass, I have time invested and I do not like hot loads that make short brass life.
If the primer pocket gets loose in one firing of 75 gr Vmax 3942 fps, then I want to back off.
 
You must log in or register to reply here.
Back
Top