A hybrid gun as of now into a game save will not be possible unless you change the attachment section into a weapon one and try it that way. Masked Hybrid Guns can be made such as the Tar-2k since your just taking the F-2k low scope and adding it on as an attachment. Since it is an attachment it will work in that slot but a weapon wouldn't. A Sniper/Pistol cannot exist unless you change the slot id to be a weapon id and ad a weapon but then the game still may not reconize it and may freeze when trying to save.