This is my impression of the APC223.
First of all, it is very well made, but it is also a very SIMPLE and sturdy design in a sense that it is made of massive metal blocks floating inside an aluminium box. It is an extrusion tube with a trunnion block nailed down by 8 torx bolts. The bolt group is very simple.
However, this simplicity doesn't address some of the issues a "military weapon" will have to resolve, but the "P" in APC means "police" or "practical", so this is never intended to be a military grade rifle.
The receiver is "porous". The charging handle slit is wide compared to Bren2 - because it opens on both sides and it is not sealed during cycling, and the opening is directly above ejection port, any sand and dirt will drop right into the magazine and get pushed into the chamber. In SCAR, the bolt carrier extends all the way to the front to seal the charging handle openings during cycling. in CZ 806 Bren 2, CZ made the charging handle non-reciprocating to seal these openings. In G36, the opening is moved to the front so dirt won't drop right into the magazine. This is the biggest weak point of the APC223. While it looks like SCAR and Bren2, it probably will not perform the same in NATO environmental tests.