Judging by the OP pics from google drive, the 16" Makasi barrel is a government profile M4 barrel with a M203 cut, but instead of being 14.5" it's extended to 16" due to NFA.Im okay with a heavier barrel...but that's just me.
The government profile was designed with the intent of having extra stiffness near the muzzle for bayonet use, and the incorrect perception that soldiers were bending M16A1 barrels by using them to pry open crates. Both are highly dubious justifications on a modern rifle.
The problem is multi fold:
1. The government profile is thinnest between the chamber and gas block, it has the least material in the segment with the highest thermal load, while simultaneously putting useless mass towards the muzzle. This makes the barrel more suspectable to thermal drift while at the same time hurts ergonomics by introducing a front heavy bias.
2. The M203 cut is purely extraneous. It sits under the handguard and serves zero practical purpose. But it does create a spot of local thermal unevenness, introduces harmonic discontinuity, and the cutout creates a stress concentration point. All of that affects accuracy and consistency of the barrel.
3. Weight distribution is completely backwards. Barrel profile plays a big role not only in the total weight of the rifle, but also in how it feels and handle. It appears they extended the thick section all the way out to the muzzle for the 18.6" barrel version. This results in an even more front heavy feel, common to many NR modern sporting rifles in Canada.


















































