In my case with the 44spl and HS-6 I saw poor accuracy and lots of unburned powder, I used Winchester large pistol primer and while not specifically a magnum designated primer I know they're universally accepted for use as such. Maybe it.was my crimp. I gave the rounds what I thought was a medium-heavy crimp. Look, I've only been reloading for about 5 years now and have much to learn and crimping always confounds me, how much is too much how much too light but I felt I gave them a sufficient crimp, maybe not. I also didnt take my chronograph because I always just see if a particular load will demonstrate accuracy potential, if it does I'll load again to see if its consistent and look at the numbers. I, like most I think, am always most interested in accuracy. I guess some people chase velocity too though.