Good job. Though as a DM for many games, is the rifle magic or is the shell/round magic?

The rifle itself is nothing but mundane components; all steel, brass, and wood. It utilizes a crank system built into its side- hence the lack of visible trigger -to spool up a coil, and, when tension is released, a series of small blades in its barrel rapidly rotate, tearing open the 'fabric'- a sort of mostly-intangible dimensional barrier -and releasing a burst of heat and energy, directed out of the front of the gun and focused by a glass lens. Functionally, it's sort of a laser gun.