.257 Roberts Loads

[lyle_destroys]

Anyone else here run a Bob? I have an older ruger that is a lazer with 100gr SMKs and SGKs. I was working on loading for a ladder test using the Hodgdon and Nosler websites. They both state that a max load for IMR4350 is 47.7 (Hodgdon) and 43.5 (Nosler). I looked at my Speer manual and it tops out at 52gr! Big difference and I couldnt even find anyone on the net running loads that hot. Im going to run my ladder test up a little higher until I see pressure, I just thought this was interesting.

 

[TomM]

That is interesting, and probably has something to do with the 257 Roberts being the only rifle cartridge that later had a +P designator.

I currently don’t own a Roberts, but have loaded for 5 of them. All preferred H4350 and a good 100 gr bullet, such as the TSX or Nosler BT. The BT worked real well on deer sized game. They seemed to top out at 46-46.5 grains. That is at least where I felt comfortable loading them to. Velocity was 2950-3000 FPS.

 

[lyle_destroys]

That is interesting, and probably has something to do with the 257 Roberts being the only rifle cartridge that later had a +P designator.

I currently don’t own a Roberts, but have loaded for 5 of them. All preferred H4350 and a good 100 gr bullet, such as the TSX or Nosler BT. The BT worked real well on deer sized game. They seemed to top out at 46-46.5 grains. That is at least where I felt comfortable loading them to. Velocity was 2950-3000 FPS.

I think that speer data was calling for around 3200fps from the test rifle at 52 grains. Would be a deer hammer if you safely get them going that fast. I may have to test it some.

 

[Muttly]

If I remember correctly, this was only at 50 yards, 5 shots rapid fire after load development was done to see how bad it was gonna get with a hot barrel.
Kimber Montana, non threaded barrel, off a bench.
100 grain Sierra Pro Hunter, CCI primer, 44.5 grains IMR 4451, Prvi 7x57 brass necked down, like using that a bit better than Nosler brass.
Pulled one shot, knew it, wasn't feeling too bad about the other 4..