was checking to see if there was any other fifty cal rounds to use for a mission and I came across B_127x99_SLAP and its tracer versions, I wondered why nobody had ever used this anywhere else since this is in unmodded Arma and after a bit more searching through the config list I think the Arma 3 devs just never added any mags that use it but left the actual ammo classname in. It seems to be properly defined and has different values to the normal fifty cal, i'm not super fluent in what the config values mean so idk for sure. although one value for velocity was higher than the normal fifty ammo, which would make sense for SLAP
now idk how easy of a job it would be to add mags for this ammo, but i know it would sure be cool to use in any of the .50 cal weapons across CUP or vanilla. plus I'd assume once you guys shine a light on this little hidden ammo type, others might begin to add their own support for it as well.