Quote:
Best Because 2. Because it allows the two barrels to be mounted closest to each other at the breech end, reducing problems regulating the points of aim of the two separate barrels.

I count at least three methods which allow the bbls to be set as close as the chopper lump.
1-conventional; 2-dovetail lump; & 3-shoe lump.
Closness on any of these is limited only by the amount necessary for regulation or the strength of the matl, whichever comes first, same with the chopper-lump.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra