Gun safe 42w x 60h x 25 d, advertised as a 42 long gun safe. Of course, we all know the manufacturer claims are phooey and I knew that going in. Loaded the safe in it's original config (typical triple U rack) and managed to get 23 long guns in, albeit tight and clumsy, and difficult to retrieve those to the rear without moving 5 or 6 in front and risking damage.
Thus invested in a 40 pack of your rifle rods, reconfigured the safe, eliminated the triple U, retained the two verticals, added a shelf to raise the shorter long guns and capped the vertical dividers.
Result = 26 long guns in two rows deep with room enough for another 15, thus revised safe capacity = 41 long guns, and only having to remove two to retrieve one in the rear.