Re: Reloading 300 Winchester Short Magnum
Well, I will admit to not being familiar with R17, and I only use Hornady 110vmax and the 180 nosler BT and AB's in mine (I actually use H4350). Furthermore, I've been loading the wsm for only about 2 years (loading rifles since '93). I have developed loads for only 2 rifles and I developed a varmint load and two hunting loads for mine and one hunting load for another. So, I wouldn't consider myself as being extremely experienced, but I would say experienced. So take what I say for what it's worth ;).
As far as R17 being "designed" for the short mag goes, there isn't one "perfect" powder for any cartidge. There are great powders, good powders, and not so good powders.
When I do load development I use many different manuals. I honestly don't care too much what brand bullet is being used because one combination may shoot much better in one rifle than another...too many variables to consider the reloading manual's "most accurate load" as gospel.
When I look at loading manuals to try to pick a starting point for load development I look at powder, bullet weight, bullet type (boat tail, flat base..) primer type, bullet brand, barrel twist ------in that order of importance imho---. You have to use the same weight bullet and the same powder when using a manual. I generally don't care too much if it is a Nosler bt, or a SMK when I start my testing. I always start testing with the minimum powder charge.
As for the powder reduction and velocity reduction goes, no I don't beleive you can make that assumption. It may be somewhat close, but not close enought to base any sort of tradjectory table off of. You simply need to chronograph your rounds imo.
I used to re-load but now I "hand-load".
-- Well, at least I try