Western weapons are made to higher tolerances (the parts fit more exactly due to higher quality machining and maufacturing) but any dirt or sand between these parts could cause problems. However; the western weapons tend to be a little more accurate. If your character is doing any long range or sniper type shooting.....an AK would not necessarily be the best weapon.
While I was in the army, (cavalry), I shot many M16A1's and A2's. The A1's were absolute crap and jammed frequently. The A2's were much, much better, but the design of the M16 is inherently less reliable than the AK. It vents gasses directly into the action of the rifle which causes it to get real dirty real fast. The bolt is much lighter than on the AK. The heavy bolt on the AK develops a lot of momentum and basically forces it's way through dirt and debris that would cause other rifles to jam. The ammunition AK's were designed to shoot has very deep grooves around the rim. This means it's easier for the extractors to operate. AK's have very loose tolerances. Dirt gets pushed out of the way and doesn't interfere with the action. AK's also have about half the parts of an M16. Less parts means less things can go wrong.
The reliability of the QBZ-95 approximates to the AK-47. It's better than the M16. The accurate of the QBZ-95 is better than the AK-47 and lower than the M16. Therefore the PLA equips the QBZ-95 5.8 mm rifle and the QBU-88 5.8 mm sniper rifle simultaneously.
QBU-88 5.8 mm Sniper Rifle
Now are you aware of the QBZ-95?