Time to do some testing bro.Work up some loads and go punch some paper.If you can drive the 155's at around 3000fps you might have a winner.If its factory ammo then i'll take 175's anyday.
Definately some good advise in this thread.
The 168's DO NOT transition well through to the sub-sonic velocity, probably the main reason people crap on them.
well I know 757Fixer loves how the 155s shoot out of his TRG. Length shouldn't be a problem as the mag on the TRG is very long.