I'm not sure that this would work in the 43...but these are flawless in my glock 42...I've run hundreds of rounds through them with no hangups/issues. Have them in 3 glock 42 magazines.
Replacement magazine springs/followers (metal followers)
Glock 42 | MagGuts
Replacement magazine springs/followers (metal followers)
Glock 42 | MagGuts