What happens if a soldier surrenders their weapon, and it has undergone significant modifications?

 In peacetime, modifications may earn you punishments. In wartime, modifications that improve function earn you curiosity and compliments, and if they’re good enough, they get adopted.

At the conclusion of the war in Ukraine, it is expected that few Ukrainian rifles will be returned in their original issued condition. Many will likely feature non-standard modifications, such as aftermarket optics, custom stocks or handguards, unique paint schemes, taped or milled adjustments, and improvised cheek risers—often crafted from tape and foam to accommodate non-issued optics. These changes, while notable, are unlikely to draw significant attention when the weapons are officially turned in.

Similar trends were observed during the conflicts in Afghanistan and Iraq, where weapon customization was common. The factory-installed top rail on M4 Carbines facilitated extensive personalization. The Mk12 SPR and its variants, in particular, exhibited significant variation, frequently reflecting the preferences of individual operators rather than adherence to unit-wide standards.

This is a repeating pattern that goes back as far back in history as weapons being issued in an organized manner.