Originally Posted by Styrak
Ah yes, because your new grenades actually use the barrel!
I got to talk to a guy from Milkor at this years ShotShow. I hefted some of their latest and greatest in 6 shooter grenade launchers and asked them if they had issues with carousel to barrel leak issues. The rep said that there is piles of leakage at that junction, and that almost all of the impulse delivered to the round was done in the carousel and that all the barrel really did was apply spin and guidance to the round. Some crazy spec ops unit requested a cut down version of their 6 shooter (basically a sawed off version) and it achieved an even higher muzzle velocity because there was a shorter barrel drag. Longer range, but bigger groupings down range with the stubby version.
I don't get to use such high breech pressures for safety reasons so I have to work on fixing the carousel to breech losses, but it's neat to see the same issue crop up in the real thing.