Other factors that determine how strong a gun safe or vault door is against a prying attacks include the length of the bolts, and whether pressure is deflected or distributed to parts besides the bolt bar.
Imagine a safe in which, when it is locked, the bolt bar goes right up to that part of the door which frames in the boltworks, lock, re-lockers etc. — that piece about 3” wide through which the bolts stick out. If the bolt bar fits up tight to that frame, and someone is prying on the door, then all the pressure is put right on the point where the bolt is attached to the bolt bar. That point of attachment and the bolt bar would take all the stress.
Now assume that when the gun safe is locked the bolt bar does not go right up to the frame, but stays, for example, 1” away. If someone pries on that door the frame will absorb most of the stress, at the point where the bolts come through the holes. Having a second point of contact makes a huge difference in strength. But some manufacturers use only 12 gauge steel there. Also, the size of the whole that the bolts go through can make a difference. If that hole is much bigger than the bolt itself, then the bolt has more room to move and more of the stress will be passed on to the bolt bar. It is best when the hole is just big enough for the bolt to go through, so any pressure immediately puts the bolt in contact with the frame. Naturally, thicker steel in the frame makes the whole unit stronger
The pictures show several methods of adding strength against pry attacks. On the left, for each bolt there is a welded guide piece to keep the bolts aligned. It also acts like a spacer that keeps the bolts back from the frame about ½”, and it makes a third point of contact that absorbs pressure from prying. The bolt bar itself needs help in this safe because it is weak. Note how much of the bolt bar is cut away to reduce material cost, and the steel is only 12 gauge to begin with.
On the right is a brand of safe we sell. Notice that the frame is ½” thick! Bolts are welded to the bar, not attached with a fastener. The bar is 2” X 1/4” and is arranged in a way that yields maximum strength. Incidentally, these safe bolts are stainless steel, not plain steel.
People come to our store from all over the state because they know they will really learn about safes here. A store or safe dealer should be willing to remove the inner door panel before you buy a gun safe, because you can learn a lot by looking inside. Don’t buy until you see what’s inside.