Kyrie,
A Darne, is an acquired taste. I like to think that is true of most double shotguns at this juncture in history. There are several idiosyncratic aspects with a Darne that make it more so. To begin with, a Darne must fit you. The stock is held on with a long wood screw, which will not allow for any bend adjustments. LOP is the only thing you can alter, economically, anyway. The action is novel, and takes most of a season of use to become familiar with. The design is light, and, unless the gun was specified to be heavier, they are often too light for most people. My 12 weighs but 6lbs, 1oz, with it's sling attached.
I know folks that have sold everything they owned and converted completely over to sliding breech guns, but, I'm not one of them-but, you have been warned.
If you choose to go down that road, do contact me if you have a question about a gun you are considering. Maybe I could be of help.
This is a photo of both of my Darnes, and the case colored R10 has had a long term role in my hunting. It is restocked to fit me, and a wonderful hunting gun.




The Darne machine gun was primarily intended for pre-WWII aircraft. If there is a lighter fully automatic weapon intended for that use, I'd be truly surprised.
I can't say I anticipate a use for one in my collection, however.


Best,
Ted