I thought the max was 8 pumps on the 392s. Unless yours is built.
Those last couple of pumps is stressful on the rifle. " Eight Is Enough ." Read this ;https://www.gatewaytoairguns.org/GTA/index.php?topic=192591.0
The new synthetic stock 392/397's are indeed rated for 10 pumps. Advisable? Who knows. Maybe this came from the same geniuses in R and D that agreed upon that lovely stock comb height.
I don't have the synthetic version, but I will offer a bit of advice for any 392, especially the new one: anything over 5 pumps, make sure you are using proper pumping technique to prevent twisting and minimize stress on the rifle.