I know, the M4 is not as good as the M2, but I have two of them and frankly I like them.
Some issues that I have ID'd:
Magazine Capcity: 5 in the tube from the factory. I have made mine 922r compliant.
I have the +2 factory extension and the Nordic +2 Nova/Super nova extensions so I now have nine in the tube.
I am about to buy two of the FFG one peice Titanium tubes.
Magazine Spring: What is the roper length spring for a 9rd tube and who makes the best prings? i am using Nordic Components trimmed to about 16" outside the extended tube as a starting point.
Follower:I am using the Noridi Components lightweight follower
Stock: The collapsible/Non collapsible spistol grip stock just doesn't seem as fast as the field stock. so I have ordered field stocks.
Bolt Handle: The stock one seems undersized. I have an over sized on one of my shotguns, was thinking baout an FFG titanium 3/4" charging handle.
Bolt Release: Anyone know where I can get a bolt release button that is brightly colored? I have a purple one on one of my M4s and want something simelar since it makes it real easy to find my shotgun when its in the rack with all the tacticool shotguns.
Trigger: Who makes the best trigger/Hammer assembly?