Old vs new 5744

Not long ago I acquired a new batch of 5744 now made in Canada as I was running low on the supply of the older stuff made in the Czech Republic. I had heard the new loads the same as the old but I found it is not the case. In my 45-70's I loaded 27 grains of the older under 500+ grain boolits for 1300fps. With the current batch I only needed 25.5 grains for 1300. Has anyone else noticed this. Also the newer stuff leaves less zombies in the barrel, higher nitro content maybe. Accuracy seems as good though. Shot some groups today at 400 yards, 5-6" horizontal X 8-10" vertical which I attribute to gusty headwinds.

your new load is close to the 5%+- mark , that I have been told is what you can expect from changing from one lot to another

you new lot is 5% faster so you need to use less

Good advice is to reduce loads by 10% and work up. In this case that would mean to start at 24.3 gr. It appears as if this might be what you did. The result is not unusual, especially considering that the two samples were from factories in different countries.