I haven't posted here much but I need a little input from ya'll. I am thinking about selling my Remington .223 LTR and getting a 16-20" flattop upper for my LEO Bushmaster M4 (yes, I'm a cop). I want to get at least MOA or better, with proper loads of course. Who makes the best and most affordable upper to fit my needs? I will keep the M4 upper for playing with but I may swap the 4POS stock for a fixed stock with a little longer pull that will fit me better....I'm 6'2".I would like to buy a complete unit that includes the bolt/carrier also.

Anyway....can ya'll point me in the right direction???

Instead of replacing the 4POS you may just get a Delta Stock addon... Which will give you a better fit... without having to take off the telescoping stock..  If you want sub MOA then get a 20" Barrel with Floating Handguards... YOu can do this two ways.. Go to Bushmaster and look at their complete uppers or you can by a barrel and get a floating handguard such as knights or something... HOwever, if it was me I would just call Bushmaster and get a VMATCH or Varmiter Upper. In a flattop or A3 configuration.  The A3 config will give you a detachable Carry handle with 1/2 MOA peeps, and 600 yards.... If you go with a detachable carry handle there is an article on 50/200 BEZO that is very good and is alot better then the BEZO that most go with, it was written by a Marine and tells how to set up A2 sights to get this...
If you want it for plinking then I would get the 20" barrel...

Ben

I would discuss your requirements with the people at Quality Parts Co./Bushmaster. I have dealt with them in the past, and they take the necessary time do determine the best way to do it, and they can build/assemble your upper to your specs at no additional cost to you. It may take them awhile though. Ask 'em what their delivery time window is before you order.