The only trust worthy safety is an open action. Control where the muzzle is pointed and double or triple all safety procedures and everything should be fine. I store with no ammunition in the firearm, the rest is academic.
That is EXACTLY how a weapon is turned in to the arms room, open chamber, bolt locked to the rear, handed to the armorer butt first.
The armorer then drops the BCG and hammer after verifying a clear chamber, closing the ejection port cover, NO MAGAZINE, leaving selector in SEMI and then placing the rifle in the M12 rack.
Safe and proper storage.
Hammer won't be dropped without the muzzle being stuffed in a clearing barrel.
I don't have a clearing barrel.
What now?
Build one. Whatever floats your boat. It's up to you.
There were no clearing barrels inside the arms rooms I managed. None.
Hammers got dropped all the time on parade fields, parking lots, in unit formations, in closed ranks and in the damn hallway while performing inspection arms, clearance drills and function checks. Clearing barrels were only required in specific locations and conditions. Muzzle discipline is part of performing by the numbers.
Dropping the hammer with the upper and lower separated is to be frowned upon. Some of us know why.
