As far as comparing the 4350s, I've never had that experience but I have with the 4831s. They are very different. Max load of IMR-4831 in my .270 Win.= 57grains. Actually that's the max in my old Speer No. Nine manual. But in my rifle I'm getting into higher than desired pressures of anything over 56.7. That manual states that when you get within a half grain of any max load you need to slow increases of propellant to 1/10th of a grain. I know that sounds anal but if I would have followed that advice I wouldn't have had a sticky bolt and flattened primer, which was what caused me to drop my load down and work slowly up and 56.7 was the magic point. And that all brings up something else that's mentioned on here. A Chronograph is a great tool. If you use it right it can keep you out of trouble. Now we all see people that post unbelieveable Velocities from time. I've posted a few. But when working a load up, if you see a questionably high velocity it should give you cause to check things out. I've had loads that were on the high side that were safe. But like when I was working my .270 load up almost 40 years ago, if I'd had a chrono I would have something that would have told me I was crossing the line. Now my my book says the max velocity for a load is 3000 FPS and my load is over 100 FPS above that, I'm going to stop increases until I conform it's not causing the case head to expand. Usually when that happens I call a load good. Also, if the velocity is swinging over 30 FPS from shot to shot I call a halt to increases. Then I'm backing off a tenth of a grain until it calms down to a dull roar. I'm no ballistician but I've learned enough to be cautious enough to keep from blowing my face off.
Last edited by Filaman; 09/27/20.
