Not the optimal powder for the caliber:
Bullseye, oh how I love that powder. It has TONS of applications, TONS! For me though, 40S&W isn't one of them!
Why? It's too fast for good load development and I shoot the 40S&W our of a semi-auto that has a reputation for having Kabooms if not loaded correctly.
I have had a KB with a Browning High Power with a fast burning powder and after that, I swore off of the stuff in that caliber.
Let me suggest some different powders for this caliber to obtain the higher velocities possible in it.
If I was dead set on using the same powder in 38spl and 40S&W my first choice would be HP-38/W231. It meters very well and it can be used with moderate loads in both calibers.
If I wasn't of that mindset I would get a can of SR4756 or Longshot for heavy bullets in the 40S&W and leave the Bullseye for my target loads in the 38spl, which is something I have used for years and years.
Longshot will give exceptional velocities with lower pressure than most, SR4756 will give you almost the same velocity with 4000psi less. That makes it a win/win to my way of thinking for my shooting combination.
Oh, there are other powders that will work. Many have suggested things I would never use but they have had some success with.
Just put my suggestion beside theirs and make a decision. If you do things safely, with good information, you should be good to go with most of the suggestions given so far!
Have fun, be safe!