In all of my years of reloading I have never run into a issue like this. I load 56 grains of Retumbo in my 6.5-284 under a 140 gr Berger Hybrid, which is pretty middle of the road in this round. I ran out last week, this week I crack open a new 8 lb'er. I load 150 cases with my Redding powder dropper. When I start looking at the cases just to make sure they are all charged, they look like they are a little more full than normal.

So, I run several of them back to my electronic scale, 56 grains. So, I am good. I start seating bullets in my seating die, and I feel them a little harder to seat than they normally are and that the depths on the first stroke are not as consistent like they normally are. Anyway, I tweak the die enough to load 50 at my normal depth. I have been thinking about this all week, totally stumped why these cases were more full than normal, and the bullets being harder to seat.

So, I head to the range this morning with these. Now, I have pressure, sticky bolt lift. I come home, and check some of the other brass I have filled on my balance beam. 56 grains. To sum it up. I never messed with my Redding dispenser that was throwing 56 grains last week, never messed with my electronic scale, even re-calibrated it. Balance beam verifies 56 grains. The only thing that is different in this whole thing is this new jug of Retumbo. Anyone know what is going on??

first place I'd start is comparing the old Retumbo ya had with the new batch....

contact company and see if they changed formulation any...

I guess it could have been mislabeled. One reason it is always advisable to restart load work up -20% with a fresh batch of powder

Pull a few old rounds and weigh.

Saddlesore has it, new lot of powder needs worked up from start loads.

I dont have any old powder, and I dont have any rounds loaded with the old powder to pull the bullets on. I can wrap my head around the fact that maybe 56 grains of the new batch is hotter than 56 grains of the old batch. It's the volume thing that has got me stumped. Isn't 56 grains of Retumbo 56 grains of Retumbo volume wise? I guess it could be lighter and hotter?

The last batch of Retumbo you bought was probably made in Scotland. This one was probably made in Australia.....In addition Hodgdon's is now making their "Extreme" series of powders.....do you really think they can change the temperature sensitivity of a powder without additional effects?

Look what's happened to H4831....the new formulation appears to be faster then the old...then look at the differences of the SAME POWDER in the ADI vs Hodgdon's manual. Let's just say the difference is outside the traditional "3% variance" considered normal for commercial powders.

Back off a few grains and find the velocity you had with the old powder then party on.