Originally Posted by lloydsmale
personaly id be looking at a slower powder if you want max velocitys out of the 257. At least as slow as 4831 and even that in my opinion is a bit fast.
Might want to check your data. According to Hodgdon reloading data center, the 4831 will not quite reach the speeds of the 4350 in any bullet weight.
H4350 looks like it will do just fine, in the velocity area for the range of 257 weight of bullets. There are a couple others that beat it in one or two bullet weights, but overall H4350 does pretty well.