Multi-pumps have stood the test of time because they are perfect for all shooters. Everyone can shoot a multi-pump. If you are young or small or don't have any muscle power, put just 3 pumps in the gun and shoot it. If you like power and can pump a lot, then go all the way up to full power with 10 pumps.
The Crosman Bushmaster ACR shoots either BBs or pellets, allowing you to shoot whatever ammo you have got on hand. Combine that with the variable number of pumps, and you have got the perfect airgun.
Get extra clips if you want to shoot pellets (same ones used by the Crosman 760 Pumpmaster) and load up so you don't have to interrupt your range time with a lot of reloading.
When you shoot steel BBs, do not shoot at hard objects or water. The BBs will ricochet! No matter what ammo you are using, remember to wear safety glasses. In fact, everyone in the vicinity of the range should wear safety glasses, even if they are not shooting. Remember to remove all pets from the range before you start shooting.