Just got myself a custom .257 Roberts.(for details , see my post in the small caliber section) In my other rifle , a Featherweight Ruger, I really only have one load that works real well,
That is a 100 gr tripple shock over 46 grans of H-414.
But This rifle has a 24 inch Douglas barrel and it is not so thin as the Ruger either. I hope to be able to get a good 3000 to 3100 fps with a 100 grain, and 2850 to 2950 with a 115 or 117 grain. In This rifle any load I use for Mule deer must be at or very near MOA.
Any sugjestions on Powder & bullet comboes that work for you ? ...tj3006

I'm using Sierra 117's and 46gr of IMR4350. From a 21" barrel I'm getting 2850 fps. Groups are right around an inch or so. Rifle was built on an '09 Argentine action.

Note:I consider this load to be a +P/Ackley load.
No excessive pressure signs in my rifle

I use any 117 or 120 gr bullet with 45.0 gr of h4350, this will get you about 2,850 fps. I use 120 partations because we have big pigs on our farm but have killed several deer with 120 speer flat bases. I don't understand using 100 gr bullets for deer in a 257.

Well Tom I Shot a mule deer buck with a 100 grain barnes tripple shock from my other roberts and it just blew he hell out of him at 100 yards.
I like the 100 for general purpose good for coyotes too...tj3006

right now I have 90 grain sierra hollow points in front of a lot of H-414 and a magnum primer.

I have a Douglas 24" barrel on my Mexican Mauser. I use 45 grains of IMR-4350 with Winchester +p cases and CCI primers and the Speer 100 grain spitzer. I fired over a chrony once and it was just over 3000fps. For Mule deer and smaller, the 100 is just fine.

I think a 100 grain bullet will do the job on a mulie real well. although i might go with a 115 to 120 and be just as happy. If I can get it to shoot I think the Nosler 110 grain acubond might be the best bullet out there for general purpose Quarter bore shooting.
The Roberts I shoot now is a little Ruger M2 RL. it has a 20" barrel that is pencil thin and I had to play with both the rifle and loads to get it to shoot.
Its a great little deer rifle, I put the tripple shock 100 grain out of it at 3140 FPS, and it gets right around MOA for me.
But the problem is the skinny little barrel heats up to fast, and you just can't shoot it much especially on a hot day.
Anyway its gonna be fun playing with this new custom.
i did up some 100 grain Sierra BTs over 43 grains of WIN-760 And some 100 grain Hornady flat bases over 44 grs of the same stuff.
I was about out of IMR-4350. So I gotta get some of that and some of the 110 grain noslers...tj3006