MR1 will shoot more than one round at once

[MR1 Maniac 11]

I just got my MR1 out from a box in my basement, and the first time i fired it, five balls came out at once. after that it would either shoot one or two at a time, need some help. was wondering if the barrel had anything to do with it?

[shunut]

Probably need to change out the detents.