How calculate Time in Barrell

[chop house]

I might have to try and figure out grt. I plan on going to range to break in new barrel and would be nice not to burn through 8208 trying to find load.
Shooting a 204R with 11 twist 24” barrel. Going to be shooting 40gvmax and Winchester brass with 205m primers
Don’t suppose any savvy grt want to help me out

grt is user friendly with a good hmint (human machine interface). the starting node of interest may well be at:

24.8 grains, load ratio 91%, 3420 fps, pressure 46k psi (20% under abs max)

this literally took 3 minutes, including firing up the program, to get this data. RUN YOUR OWN NUMBERS and still USE A BOOK TO DO A SANITY CHECK. i have not finished my first cup of coffee, and am prone to making errors this early in morning.

i would suggest becoming a user. there also is a support super group on, i believe, discord, but it requires a sign-up.