The M79 and XM148 grenade launchers were single-shot, and the repeating T148E1 grenade launcher was unreliable, so a request was made to China Lake engineers. SEAL Teams were pleased with the resultant pump-action grenade launcher, since the tubular magazine held three 40x46mm grenades, and so with one grenade in the chamber, four grenades could be fired rapidly before reloading. In fact, a skilled operator could fire four aimed shots before the first one landed.