I see Exotic Ammo has listed the M-79 as being in stock again. Any chance you guys can bring in some more?
You only need to take 1mm off the barrel wall to bring it to M203 40mm specs (a stock Tac-79 barrel is 39.4mm internal diameter). The Tac-79 is designed for WAY higher pressure rounds than an M203 so will have plenty of strength left after shaving the barrel down a bit for shooting M203 spec rounds, but I wouldn't fire any tear gas canister rounds out of it after