No.SA375: 3/8" TRUMARK® Steel-Ball Ammo has been chosen for it’s larger size when compared to the 5/16". Although larger, it's not too large. Trumark does not recommend ammo that is larger than 3/8" since it becomes too heavy, and is unsafe if used improperly. About twice the weight of the 5/16" size, Trumark’s 3/8"ammo is still heavy enough for controlling rodents or hunting small game with wrist-braced slingshots in areas where firearms are not appropriate. Perfectly ROUND, it feels good in the pouch, and lets you concentrate on your target as you get ready to shoot. (Grade B ammo has a "flat spot" that is found on cheaper metal balls designed to shake-mix-twirl paint in spray cans). If accuracy is your goal, avoid "paint can balls" and always shoot Grade A Trumark ammo for the best results! 225 Yd. Range with Trumark sling shots: 70 shots per bag. SEE >1/2" Marbles | 5/16" Steel-Balls.