If you have an old dead hard drive tear it apart and pull the two curved magnets out of it. They are STUPID strong. Somewhere I have a pic of a loaded 1911 being held onto one of these by the last inch of barrel hanging off the side of my safe, can’t find it so I took another.
I suggest you wrap said magnet in some kind of cloth, 1) to protect the gun finish an 2) to aid in removing the thing. These are HELLA strong. I also use them on my oil pan and transmission pans to catch any errant metal shavings. I’d say they will hold about 10 lbs.
Cheers,
Craig6