Securing Safe To Wood Framing
Roy;
Your new safe; by all means, use FOUR bolts to hold it down, not two; You mentioned it only had two bolt holes; drill two more! (Actually, you'll probably need to drill all four, as the hold down bolts need to be fairly near the four corners of the safe. ) It's not that big of a job. A safe with only two hold down bolts is very easy to break loose using a pry bar.
Securing a safe to a floor depends entirely on how the floor is made, and there are too many different types of construction to give a detailed explanation of how to do it. Just as an example, my safe has four hold down bolts, each 5/8"; the safe sits on 3/4" hard wood flooring which is on 3/4" plywood sub-floor; underneath the sub floor, I took two 48" lengths of 4" channel iron, drilled 4 screw holes in each channel iron, screwed the channels to the sub floor with the flanges down, then the four hold down bolts each have 3 flat washers, 2", 21/2" and 3" dia, under the bolt heads, the bolts then go through the safe bottom, 1 1/2" of wood flooring, and through the channel iron which is maybe 3/16"; using the two 4" wide X 48" long channel irons spreads the load out over a great distance, giving it a LOT of physical strength; also....each bolt has a 1/8" X 2" flat washer under the channel iron, all held in place by TWO lock nuts on each bolt, the 4 bottom nuts being castellated, and the bolts are drilled a 1/8" cotter pin secures each bolt.
Even if thieves were to get in the basement they still won't see my elaborate hold-down "scheme", as the two channel irons are on either side of a 2 X 12 floor joist, and I have a 4ft X 5ft piece of 1/2" plywood screwed in place to two floor joists with about twelve 2" drywall screws on either side; I then have a four foot 4X4 "strong-back" in the middle of the plywood with a 4" steel post between it and the concrete floor; (the post is partly for concealment and partly to prevent any floor "sag" from the weight of the safe. If anyone ever decides to burgle the safe, they best have some effective "hearing protection" as I "invented" the loudest home made alarm you'll ever hear! (The bell for the alarm is outside and on the roof. )
Probably the best protection for a gun collection is.........be extremely cautious about "WHO" knows you have guns. IMO, about 75% burglaries involving guns are the result of the wrong people knowing where the guns were.
Good Luck!
Charley C