Finally shot some Imr4451. Watch out, it might hit you with its cane as it takes the retirement bus to the target. Max charge of 41.1gr and a Nosler custom comp bullet went a blazing 2556 fps. The barrel only has 60 rounds down it, it might pick up 300fps. Oops too many zeros. It did put down a pretty decent group of six shots...for having a powder variance of 1.4 grains. Batteries died in the chronograph before we could test off the shelf winchester 125gr. Maybe next time.