What a great forum..Thanks for the welcome and I am impressed with the responses and quickness of reply...
I think Colin1 is right about the guns just ripping through the zippers, but if this were a common problem, wouldn't there be a solution?
I have asked a number of G model pilots and mechanics but none have been able to answer this..
Did the zippers on the chin turret ever get stuck because they were coated with ice? Those high altitudes and temperature differences must have created some moisture and it would be hard to believe...