I've seen a lot of debate on which BCG to purchase, but I haven't seen any arguments for weight.  Can anybody tell me why I would want a heaveir BCG?  I like the quality that Les Bear is known for, but they sell BCG that are heavier than normal.  Why?  And do I want one heavier for my build?

The whole AR concept was designed with the heavier, M16 BC.  All, or nearly all, the bastardized, lightened BCs you see out there are PC design and are needless.  The system runs better and more reliably with the heavier BC.

Like Mongo already said, when you figure the gas system was built around certain weights, it is hard to imagine why you would want a light BC unless you were doing something special.

A heavy BC is good if you are shooting  heavy bullets( 68,75 80 gr.) at long range. It keeps the bolt locked longer , reduces B.C.G. velocity and gives your brass longer life by letting the pressure in the barrel  bleed off before the bolt tries to unlock. Many of the service rifles i build have as much as 3.0 oz. of tungsten added to the BC for shooting 80 gr, bullets out to 600 yds. It does make a difference.                    PATRIOT ARMORY.