What is required to launch the special grenades with the M-1? I don't want the real grenades, but think I would like to play around with the practice grenades. All I have seen are pictures, but don't know anything about what all is required. Do the grenades fit over the muzzle or is there an attachment that fits over the muzzle that the grenade fits on or what? I understand there is a special grenade sight for it--am I correct? And is it a blank cartridge that launches the grenade? Is all the equipment including cartridges and practice grenades available for purchase? If so, where at at what price? Does anyone make a crimper so you can reload the cartridges to launch the practice grenades?