Swords no longer receive bonus ammo from reserve mods. I believe this is because sword ammo pool is counted as magazine size (thus why they benefit from backup mag perks), and don't have a reserve stat to be affected by the mods. Swords are already fairly niche weapons for most content, so it's not like they'd be broken by fixing this issue. It'd just be very nice to actually let swords be used with these mods.