If someone breaks in when your not home, That is one place they will look. And if need be they will take the safe with them. If it's not secured to the floor. What i did with my home defence shot gun was mount it behind the dresser on rubber coated hooks. Easy access. And out of sight and a out of mind to a would be robber.
Would a cable with loop boted to the wall or a chain and then a cable lock through the loop/chain and the shotgun action not do what you wanted for far less dollars?
Yes, an intruder with plenty of time could unbolt the cable/cut the chain and take the lot with him but the risk and consequences are relatively low. Meanwhile it remains extremely accessible to you, can remain loaded, and is completely secure when locked. Just a thought.