Waiting for my barrel to get here for a .260 I'm building and I need some good loads. I picked these bullets as they have a very high BC. for their weight and they won't take up as much powder space as the 140gr. Bergers I have for my 6.5-284. I have on hand some H1000, H4831sc, RL22 and Magpro. I'd be willing to go buy whatever I need though.
Thanks in advance for your help.
I'm cooking up some loads for SMK 123 (and also 107s) using IMR-4064. Based on what I've heard here I think I will also try some H-414 recipes. (I tried H-414 with the 107s but my groups widened.) The 123 was designed after the last revision of the Sierra reloading manual so there are no recipes in the book. I called Sierra and they said for me to start with the recipes for the 120 grain SMK. Even though the 123 is heavier, it might be faster coming out of the muzzle than the 120 because it has a smaller bearing surface. Anybody have experience with this newer design from Sierra?
I use 45 GR IMR 4350 210M primers 123SMK brass is either Rem or Nosler I keep the separate but they all shoot the same, this is a great bug hole load I also used 120 SMK and had same results COAL 2.80 I put a 123 into a big WT last year at around 300 yards never went anywhere.
I was never able to get 4350 to shoot well with my 1-9" .260 under the 123 gr SMK. I'm sure I'm the only one that's ever had this trouble before because 260 shooters rave about 4350.
I've tried about alot of powders and while I'm still in the load development phase I'll say I've had the best luck with 4064 and 4831 loaded close to a full grain off max and .010" off the lands. I know you asked about 4831sc, and I can't help too much with that, only to lend my advice from what I've learned using standard 4831.
I'll update this will exact powder weights when I'm near my load books next.