Overall in large sample sizes, LWRC has more variation in QC/small issues, though nothing that makes them not a viable choice.
What LMT mono uppers do is:
- Durability. Breaking or bending a rail with an MRP/MLC would be quite the show.
- Rail deflection under any load is the least on the market. Mainly matters with IR lasers and iron sight use; however, does effect bipod loading and torque applied back to barrel nut.
- Tying in with rail deflection, bolt life/bolt wear especially in the lugs, is much longer in hard use than any conventional upper. One can expect bolt lug breakage between 6,000-15,000 rounds on average with true Milspec bolts and any conventional carbine length gas upper; with LMT’s I haven’t seen a single bolt lug failure with dozens of uppers with more than 30k rounds each on them- mostly suppressed.
- Quick change barrels
- In general they tend to show much less POI shift between different ammo types and/or different lot numbers.
As I said in the first post- depending on use, LMT’s may be the “best” AR upper platform on the market. May be. Other uppers and designs can be, and are good or very good. However, there is no “better” 16” upper than an LMT MLR with appropriate barrel.