257 Roberts question

[shadow]

I have a 257 Roberts that I just am breaking in. I am using 117 grain Hornady SST's and the rifle refuses to shoot them well. I have used IMR 4350 and IMR 4831, fed 210 match primers and all sorts of seating depths, powder charges, etc., and the best group I can get is around 1.5" at best. Here is the crazy part. I also have a box of Winchester 117gr +P factory ammo, with the power point bullets that look more like a round nose! These shoot under 0.400 in ther rifle, so I know the rifle is not the problem. I have reloaded for years, so don't need advice on reloading, etc., but need to know if anyone has been using 117 grain bullets and faster powders with success and if so, what bullets and powders. Also, anyone know what powder Winchester is using in this round, WW 760? Any advice would be much appreciated.

Regards

Shadow

 

[todbartell]

Ive never loaded for a 257 Bob, but have loaded SSTs in a few guns. Ive found that some guns just plain wont shoot them.

Id try the 115 gr Nosler Ballistic Tip if you're looking for something to perform along the lines of the SST. Personally Id try some Nosler 110 gr Accubonds.

woot, nana time!
​

 

[beretta boy]

x 2 for the Nosler 115 Ballistic Tips.

Winchester likely uses something very much like W760, however, the
stuff they use at East Alton isn't the same as what we get in 1lb. cans.

Try a different bullet first. IMR4350 is usually a good bet for the .257, but
IMR 4064, RL-19 & H4350 & H 4831.

Never had problems with Fed. GM210M primers.

 

[grouch]

What is the twist rate in your barrel? the fact that it shoots a shorter bullet well raises the suspicion that you've got too slow a twist to stabilise the long bullet. I've known people to have that problem with slower than 1 in 10 twist and 117gr bullets.

 

[SuperCub]

I'm having good luck in my 257R with shorter, flat base bullets in 100gr. For deer, a good 100gr is all that is needed.

I think your problem is related to the bullet length, not weight. BT bullets are pretty long bullets compared to flat base RNs.

 

[shadow]

257 Roberts

Thanks Guys

Twist rate isn't the problem, nor do I think bullet length. Factory 117 grain ammo shoots under 0.4, 115 Hornady SST just won't group and in 25 cal. they are a flat base. Thinking that maybe the sst bullet just won't work in my rifle and will try some 115 gr Noslers or Sierras in a boat tail. 100 Grains are nice, but would rather use the heavier bullet.

Regards

Shadow