Most 'safes' arent. They are classed only as '"securable cabinets ''usually having only a 1/4"or less steel in walls and/or door. They are quick work for a disc cutter and many also susceptible to door flipping( pry attacks). Some brands can be pried open with screw driver, others can be virtually pry proof, but generally the fact is the metal thickness is what it is and for a determined burglar with portable powertools they are always going to be quick work. Id choose something economical with some sort of reputation for anti-prying at least.
Real secure options if you want them are ''real safes" as used by commercial companies, banks, supermarkets etc for cash holdings. They range from 1/2" steel walls to dual skin walls and concrete mix, up to bank level safes with walls several inches thick.Weight varies from a few hundred pounds to a couple of tons. Very expensive new, they can be found real cheap on the used market, particularly if a bank branch or store is closing down. Some will even give the safe away free if you pay to remove it. Large locksmith or safe selling companies will often have used refurbed units on the floor for sale at a fraction the price of new ones. Obviously check the weight before you buy to ensure what you can move and place in the home. Manouvering large safes on a solid floor can be done rolling them into position on broomsticks or metal pipe sections pretty easily.
For any safe, particularly lightweight fake gunsafes a few suggestions are
1. back them up with alarms or home security system
2. Hide or disguise them once in place. especially gunsafes with the gimmick spoke handles. Vauilt spoke handles are only needed for vault doors where the bolt work weighs hundreds of piounds. On a security cabinet they are nothing more than a sales gimmick and advertisement for theives. Cut them off or in some cases they can be unscrewed leaving a basic hub or knob .
3. Place safes in a corner of the room so walls protect two sides of the safe, with the door opening away from the nearest wall. This is as flipping the door( prying it open) requires levering it the other way and it cant be done as easily with a wall right next to it
4. bolt it down, even heavy safes get stolen. Also flip attacks are easier if the burglar can topple the safe and pry it standing over it
5. Use other furniture in the room to further limit access to the safe. Bolt any other cabinets, beer fridge, applicable sofa next to it
6. Add internal racks and chains to firearms inside if you want. A burglar who cuts a handhole in a door or wall of the safe to withdraw contents may have to enlarge the hole to get tools inside to deal with the second layer of defence.
7. Dont store power tools near the safe or lock them out of sight too, opportunistic theives may use what is easily at hand
8. Dont brag about your safe or show it to your buddies. Word spreads easily. The wrong person at a diner or work overhears you have a fancy glossy safe , you may get a visit one night. Three of the highest security grade safes ever made, the Wormald 8000, Chubb Isolator and TRTL 60x6's which need expert teams and heavy machinery to crack can still be opened quickly if the owner has a gun pointed at his head