Home Forums Reloading Big Game Rifles .257 Roberts fav's

That 90 gr. GMX should be a "killer"... I bet 3200+ fps is possible

It'll be nice if the 90's shoot. Hats off to Hornady for posting the + P data in their reloading manual like Speer is doing.

I think it's possible that part of my problem with accuracy is that I've been sticking to the NON +P published data in the Barnes manual due to using Remington cases, which are NON + P. I've since prepped the Winchester +P cases for reloading, (not that it particularly matters in a Mkii), just to stick with the advice of the reloading manual. I"ll use the Rem cases loaded with lead bullets for my wife to practice shooting at lower pressure levels. I"ve got some Sierra match 100 grainers for her to practice with.

Also, I've taken the Ruger apart and torqued the stock in accordance to what I've read on this forum. The mag hinge plate does close a little easier since I've done this, so hopefully this will help.

When is stops raining here in California, (home of the fruits and nuts), I'll head to the range and do some testing.

I've been shooting IMR 4350 in a Ruger UL 20" 257 Roberts. The standard 46gr IMR 4350 with a Nosler 100 Partition. RP case, BR2 primer, 2.912 OAL, .002 off the lands. Average 3030fps at sea level 40 degrees using a ProChrono Digital chronograph. I'm no target shooter, but can do 1-1 1/4", 3 shots@ 100yards.

Recently changed over to H4350. Same bullet, case, primer and OAL.

3 shot Average fps, @ 35 degrees sea level. Same ProChrono Digital chronograph.

46.5 = 3060 average fps.
47.0 = 3105 average fps
47.5 = 3164 average fps
48.0 = 3171 average fps

Settled on 47.3 @ about 3135fps for the best accuracy that I could do. 5 shots into 1-1/8" @ 100.

Worked up from this data......