Stupid rail question-full vs half

[Slimjim9]

What can you do with a full rail like this:
http://www.browning.com/products/fi...rrent-production/buck-mark-contour-urx-5.html

that you can't do with a half rail like this:
http://www.browning.com/products/fi...-production/buck-mark-plus-practical-urx.html

 

[carguychris]

Vary the optic location so it effectively acts as an adjustable counterweight.

Mount a physically long optic without excess overhang at the rear.

Mount multiple co-witnessed optics.

 

[NoSecondBest]

What he said +1