I had one of the replica Broomhandles. They were quite popular back in the 1960s/70s when real Broomhandles were very scarce and expensive. (they still are, but the flood of chinese guns in the 80s/90s reduced the market for the replicas.
They are made to field strip like the real thing. The spring(s) are weak, the chambers were not cut full depth, the firing pins were a tad too short to fire live ammo, and the barrels were plugged with a steel rod. They were made from a zinc alloy.
In good shape, they are very difficult to tell from a real gun, at a glance. IN bad shape, its pretty obvious, as steel rusts, while zinc corrodes with a different color.
Real broomhandles have serial numbers. Replicas do not.
All else being equal (and it almost never is) bigger bullets tend to work better.