Hello there Ray and welcome to this side of the forum
If I were you, I'd approach the landowners who let you go lamping with the dogs, I'm pretty sure they would allow you to shoot on their land as you would be continuing to do them the favour of pest control Worth a try? Deffinately
HOWEVER:
First thing is first:
Go find a club or range (as been said, everyone (well almost everyone) will be delighted to talk, show and let you shoot their pride and joy.
Secondly handling a few different guns will allow you to decide which powerplant you like best, Springer, PCP or Co2.