Doing a project on a cold weather Colt right now.
M4 Magpul version, FDE.
Magpull oversized triggerguard for gloves.
No optic, rear plastic sight replaced with much more durable detach carry handle & A2 sights.
Nothing electric on it at all.
Batteries can die quick in extreme cold temps.
No optic, even the best glass can fog or blur if it gets cold, wet & snowy enough.
Very basic Vickers sling, instantly adjustable via a short pull-strap, reduce fumbling with gloves or shooting mittens.
Quick detach push-button rear swivel to get out of it in a hurry in any position.
Extended BCM charging latch for gloves.
Also replaced Colt carrier group with the BCM group, extra power on the extractor spring, at a minimum.
Otherwise, nothing added to increase weight or bulk.
I want light & simple.
Denis