.257 Roberts

[rainydays]

Trying to work up some different loads for my Ruger .257 Roberts M77 MII.
Right now I'm using Sierra GK in 100 gr. Was wondering if anyone else out there loads for the Bob. Mine has a 1in 10 twist.
With this barrel would something heavier like 115 or 117 be a better match for the barrel than the 100's. Used mainly for whitetails out to 300 yards. Thanks for any advice I might get.--tr

[Rocky Raab]

With that twist rate, it would almost surely be better with the heavier bullets. I'd try the Nosler 115 BT first, followed by any of the many 120 softpoints. I haven't examined any in a while, but I believe most of the 117s are pretty blunt roundnoses. They were meant for the .25-35 WCF are are a bit soft for the Bob as well as blunt.

[Catfish]

I load for a .257 AI with a 1 in 12 twist and it will still group pretty good with the Serria 117 gn. bullets. I built it for a varmint rifle, but did lone it to a friend to hunt antlope with. He fire 1 shot at an antlope, the guide he had said it was 450 yrds., it fell over dead and the hunt was over. With the 1 in. 10 twist I would guess you would get better groupes with the 117 gn. bullets.

[Cossack]

You can have your cake and it it too: try 100 Barnes TSX. It's a longer bullet becasue it's made of copper alloy but lighter so you can push it faster for the kenetic energy effect. Becasue it does not come apart, it has terrific terminal performance icluding penetration.

[Evan03]

how would you say your loads are acuracy wise with the 100gr bullets.

i shoot a 2506 and never step over the 100gr bullet line. mine shoots 75-100gr bullets very well.

i have tried hornadys 117gr facotry ammo with little acuracy succes. my reloads with 100s 85s and 75s shoot much better.

if i had a 257roberts i would try anything before i tried the 100s and lighter. mainly the 100s as an all around deer varmit size bullet

[rainydays]

My .257 at best shoots 1.25 to 1.5 at a hundred yards. Have shot five deer in Idaho with it with the 100's, but none were over 75 yards. Never worried to much about it because never had any long range shooting. Out here long range shooting is pretty much the norm. Also tried some 75's this summer and they shot absolutely terrible in my gun. Going to take Rocky's advice and pick up some 115's or more this weekend when I can get to town
and start working up some new loads. May also be that this particular rifle won't shoot any better than it is without doing some work to it. Still alot of fun though working up a new load.
Do appreciate the feedback though. I'll be trying some new loads next week. I'll make a post .--tr

[Lone Star]

Sierra makes two pointed 117s - a SPT and a SBT - for long range shooting. IME the Sierras lack a bit in structural integrity, tending to shed their jackets in game. But they do kill well.

The 10" twist rate is fine for 100-grain bullets, particularly the longer versions like the Nosler BTips and the Barnes X-bullets. It is the length of the bullet which primarily determines its stability at a specific spin rate, not just its weight.

One of my .250s has a 12" twist and it has less accuracy with the longer 100s than it does with 85s or short 100s, particularly when top velocities are not used. This suggests that the 12" twist rate may be marginal for the long 100s. The 10" rate should be perfect, IMO anyway.