From personal experience, I know that you can hold your bare hand over the breech end and the Nerf goes screaming out the barrel just as fast as when the breech is sealed. The Nerf is so light, it builds up very little pressure in the breech. Leakage affects are efficiency but otherwise is not a problem as long as it leaks the same amount each shot. My autoloader magazine has two PVC to PVC joints at each end with no seal. Leaks quite a bit but shot to shot velocity is consistent.
By holding the cap against your shoulder like a shoulder stock it would easily work with any kind of decent seal. It would not take much fabrication to Make an L shaped flip lever / locking mechanism that would swing down from the clamping bolt and hold the cap in place.
Carefully planned irresponsibility is the KEY to mental health.
If you haven't grown up by age 50........
You don't have to......
Last edited by Boom Master : 12-12-2012 at 11:07 AM.