Anyone using IMR 4350 and Sierra 117gr. Game King bullets in .257 Roberts ? Can you suggest a load for this combination ? Thanks.

I generally use around 45-46 grains of IMR4350 with 115-120 grain bullets, which tends to group well in most .257s.

My son has a 257 Roberts built on a 98 action.
It was rather picky about what it would shoot.
I tried several bullets from 100 to 120 grains but I got it to consistently group under MOA with IMR-4350 and the Sierra 117 gr. Gameking you speak of.
I don’t remember the exact charge off the top of my head but when I get home I’ll look at my load book and see what it is.

I've had good luck with H4350 also, with Hornady and Nosler 115 to 120 grain bullets, but the velocity was a fuzz better with the IMR version.

Wizard,
I loaded those 117’s for my son’s 257 with 35.2 grains of IMR-4350.
Probably a little anemic but it’s accurate in his rifle.
That came out of Sierra’s 5th edition manual.

Lilja barrel on a Mexican Mauser here. 42g and the 117. Any higher and my brass shows pressure signs.

What's the velocity? And what are the pressure signs?

I have some 117gr. Sierras---both Game Kings and Pro Hunters that I am going to list in the Classifieds soon!

Hip