Originally Posted by KKoTerski
That's smaller than the orings on the bolt guide, which slide along the inside of the bolt so I highly doubt that. My guess is 015 or 016.
Its definitely small. First couple batches you had to take off the oring to get the bolt out. The new batches now have a very small oring so you can take the bolt out of the can without taking off that oring. I'm going to have to agree its something small like an 012. I'll have to check my oring when I get home though.