Lewis Machine & Tool (LMT)
Lewis Machine and Tool also known as LMT is one of my favorite products. I own a LMT MRP and it works very well both suppressed (no gas in the face even with a 10.5" barrel DI!) and unsupressed with short or long barrels in any caliber just by changing the barrel and nothing else. What ever Karl Lewis does to these rifles is nothing short of engineering miracles. The monolithic rail system also makes it the strongest upper built while being minutes away from a caliber or barrel length change to tailor your mission.