The prime idea in shooting from the bench is NOT to make a "springer" type rifle unable to reciol.
I use my open palm on the forearm, hold the rifle loose, but completelly with the trigger hand, and get square bearing of the buttpad on the sholder.
A springer needs this "float" to accomplish the recoil cycle, otherwisethe reaction of it's powerplants discharge forces get translated into inconsistant movements of the gun.
Noone could (or should) hope to try to contain a springers movement during firing it!
CO2 and Pneumatics may be rested firmlly upon sandbags, as their discharge is not dependent on such a severe a mechanical reaction.
No matter what type of rifle is fired, NEVER rest the barrel, rest the forearm!
Even shooters of recoiless actions, should use the open palm. (Note the Olympians...).
HTH,
ZVP