I'm not sure where you are located, but here in PA the Accurate line of powders are often difficult to purchase, as not many shops carry them.

Skip gave you an excellent piece of advise. If you are determined that your loads must be magnum loads, consider 2400. I forgot all about that powder. It is an excellent choice for magnum loads.

For what it's worth, I shoot 38 specials out of my 627-5, at a 120 power factor (bullet weight X velocity / 1000). I use a 158 grain Berry's plated bullet at 775 fps. It's a nice soft shooting, accurate load that I can use for ICORE competitions.