Home Forums Hunting & Shooting Hunting Rifles .257 Roberts +p

First off, I better get the disclaimer out of the way....

Use this data at your own risk.. I spent lots of time and powder working up to this load. I do not recommend that you try it..

On to the range report.. this is more of an observation post than me sharing my data post.

I recently purchased a Ruger #1 RSI chambered for the lovely .257 Roberts.

A buddy of mine suggested a load of 41.5 of IMR 4350 launching a 117 Sierra BTSP for potent hunting. With his rifle and a 23" barrel, he is getting 2830 FPS and great accuracy. I loaded a few of these up and shot a couple MOA groups with it and was plenty happy until I ruined a good load by running it through the chronograph.

I was only getting 2680ish FPS out of my 20" tube and I was unhappy with how anemic the load was through my rifle.

The only Bob brass available right now is Nosler +p stamped brass, so naturally a purchased a lifetime supply of it. I was showing ZERO pressure signs with 41.5 of IMR 4350 so I decided I was going to step up .5 gr at a time until I started showing pressure signs.

Long story short, it wasn't until 46 gr. Of IMR 4350 and starting to run out of case capacity (just beginning to compress) that the corners of the primers began to start to flatten. I loaded several of each load to make sure the pressure signs were consistent.

The three on the left are 46 gr., the one on the right is 45.5 gr there is also less than .002 of web growth..



This load averages right at 2980 for three shots through my 20" barrel. The data is pretty much printed Ackley Improved Data.



Being a holiday weekend the shooting ranges were way busy so this shooting was done off a very uncomfortable folding picnic table and rest but was still able to get real close to MOA accuracy out of it. As my buddy said, just goes to show how each rifle has its own DNA so to speak.





Thanks for reading and happy shooting!

Todd