Or the simple way to think if it is 1 inch group per 100 yards being... Meh, acceptable (never settle for less). That turns into really good if you are keeping a 8" group at 800 yards (sub MOA by the math lesson above).
The farther out you go, the more variables you have to deal with, and the more impact to the POI from little influences you have, like simply having to squeeze the rear bag a little harder than usual.
When I get out to practice, I keep my plates at 1.50 MOA or less. My 735 plate is an 8" circle.
If your groups are flat and wide (400 yard group is 1" tall x 4" long), especially at longer distances, then you are doing really good, just need to deal with either wind, or your shooting position.