I just now linked a report in another comment, the silencer is part of the 1966 experimental kit, and it was found to be largely ineffective.
If there is any reason for bias towards a revolver over a 1911, I suspect a more plausible explanation either in absolute fact or in perception is that a Brown style action like in a 1911 can be pushed out of battery and made inoperable if the barrel is pushed on. It isn’t normally a concern, but you can imagine why a tunnel rat might worry about it. That is just speculation.
I just now linked a report in another comment, the silencer is part of the 1966 experimental kit, and it was found to be largely ineffective.
If there is any reason for bias towards a revolver over a 1911, I suspect a more plausible explanation either in absolute fact or in perception is that a Brown style action like in a 1911 can be pushed out of battery and made inoperable if the barrel is pushed on. It isn’t normally a concern, but you can imagine why a tunnel rat might worry about it. That is just speculation.