I've used 10 to 15 pounds of Olde Eynsford in my .45, 50, 54 and .58 calibers. I have not had good results with OE 3F, but OE 2F and OE 1 1/2F are wonderful powders . Craig Kirkland, owner of Bear River Powder, a Goex Master Distributor, told me a couple of years ago that the only caliber he had good results with using OE 3F was a .38-55 cartridge rifle (I think it was). I think it can be worked with to perform well, some shooters do. But my first choice is OE 1/2F, even with .40 caliber. There is little difference between OE 2F and OE 1 1/2F in velocity per grain, and accuracy is similar, but my first choice is OE 1 1/2F, even with .40 caliber. I have three .40 caliber rifles I made, but I don't think I've shot OE in them, I don't shoot them anymore. I did use Swiss 1 1/2F in a .40 once with excellent accuracy, but I have found OE 1 1/2F superior to Swiss 1 1/2F. See my posts about Olde Eynsford in this forum.