Grendelize the M4 Carbine

[stanc]

Suppose the decision was made to replace 5.56 NATO with 6.5 Grendel, and you were tasked with converting and upgrading the military's M4 carbine inventory.

You are free to make whatever modifications you wish (to include changing the barrel length), except your redesign must incorporate:

- The standard upper and lower receivers
- A telescoping stock adjustable for LOP
- The standard bayonet lug, correctly positioned on the barrel

What changes would you make? What new components and accessories would you use? Would you keep the 4X ACOG, or use a different optic?

[BluntForceTrauma]

16" mid-length barrel, for starters.

Magpul ACS stock for battery storage.

New optic. Somebody has a 1&4 that switches between magnifications by throwing a lever. I'd make a lightweight 1&6 version.

[cory]

First off I'd push for a new policy in which every Marine would be issued a rifle at MOS School that would be theirs for life. The same would go for combat MOSs of other branches. (It would be stamped with a serial number making it illegal for anyone else to own for the next 40 years that wasn't the veteran's heir.)

Anyways, I'd stick with the standard 14.5" barrel and standard components for the issued rifle with irons. I'd then put in place a program that would qualify optics and accessories approved for use. An acog with a reticle specifically designed for a 123gr smk load would be a priority. Other top priorities would be a SS/nitrided 18" & 12" barrel.

As always there would be commander's discretion where they'd be encouraged to allow E-5s and up the freedom to choice modify their rifles as they see fit and E1-E4 would require squad leader/superior's authorization. A yearly allotment would be issued in which they could use through the company/battalion armorer to modify their rifle to their needs. An optic allotment would be issued per enlistment that would be used through the company/battalion armorer as well.

Battalions/Units would still get funding for specialty weapons/optics. (MMGs, LMGs, Mortars, DMRs, NVGs, Infrared, DMR optics,......)

[sneaky one]

Add the smallest suppressor made.