The evidence shown empirically says no – for these particular guns. :^)
But, considering all the trouble they went through with the periscope and stuff, it would seem prudent and not a lot of extra work to remotely fire any gun you are abusing with an off-label use, in case it’s not as stable and indestructible as you thought it was. The Mythbusters usually don’t fire off gun experiments by hand unless they’re sure they have complete control of the situation.
