These things happen sometimes Georg when one is in a hurry!
Looks like Mr. Moore of "Moore Silencer Co.", New York was having tests done with the US Army by 1911, where his "improved model" was rated as almost as good as the Maxim. The patent drawings I posted above are his improved model of which 100 were ordered by the US War Department in 1913.
The source for that is here and notice gentlemen that you can download your own copy as well as read online. Archive.org is well worth supporting by the way, if you don't want G--gle controlling everything.
Wouldn't surprise me if Moore silencers were purchased, if Maxims were not available in sufficient number.