looking for a good powder to load in a 223 rem and a 257 roberts ..

There are a lot of good powders to use but a lot depends on what bullet your going to be using . Myself I use IMR4350 and RL-19 with a 115 gr bullet in my 257Roberts and IMR4198 in my 223 rem with a 40 gr bullet . As long as I have been reloading I have never found one powder that would do it all or be the best in all guns it was used in , thats why everyone tries different load combinations . Hal

Varget works quite well in the .223 and also in the .257 Roberts up to 100 grain bullets.....from there the slower powders are best in the Roberts.

If you want to use the 75 grain bullets for varminting in the Roberts Varget will work fine for both cartridges.

Go give the nod to Varget if you want the same powder for both rounds... I load varget in everything .270 and under and I have yet to find a load that I couldnt tweak a bit to get it to shoot.

I second the Hodgdon Varget for the .223, I use it in my .223 exclusively. Sorry, can't help you on the Roberts.

For the .223 I use IMR 3031 and for .25 caliber bullets I use IMR 4350,but that's my choice...

I load 748 in the 223 and H380 or I4350 in the 257. I think the H380 gives tighter groups.