Nial,
I was intrigued with what you posted, and went to try it out. It is not possible on an R model, the triggers trip the sears as the breech gets close to the end of the barrels. When I tried what you described on my V model, the same exact thing happened, the triggers tripped the sears as the breech got close.
Are you sure your gun is a V?
My take on the procedure it is this-I don't want my non-operating hand near the closing breech on a Darne, that my operating hand is busy closing. If something gets pinched between fixed barrels and breech, as the breech is closing, it will most definitely NOT be a day brightener for me.
Don't ask me how I know this.
I won't argue with anyone else's success, but, it isn't the way I go about it.

Plastic snap caps suck, Mr. Brown. The Darne was just making sure you knew that.


Best,
Ted