It impossible for sinkieland to achieve self sufficiency far as weaponry is concern.
U still need to get the raw materials and spare parts from overseas suppliers. Take bionix for example, the engine was imported from USA, bushmaster main gun also from USA. Suspension likely from another overseas supplier. I reckon most components within are imported overseas. We merely serve as a assembly point.
If you maintain self sufficiency in small arms, weapons, and some crew served weapons and anti tank weapons, you are fine. You can make a long and painful resistance for the enemy.