My cousin had his kid leavee a part of box 22lr in the truck, cuosin got popped for speeding, being a non violant DV he got hit with felon with ammo, cant think of it but may have been tulsa county. he did 90 days then got the rest suspended.There's no OK law against felons possessing ammo.
Federal law on the other hand, says it's illegal. But to be honest, you'd probably have to work pretty hard to get them worked up about it.