The M193 load is the only one I’ll use in our AR’s and M16.I prefer the original twist rate of the M16 too.If the situation deteriorates to point that you actually have to shoot people,then the inhumanity of the wounds inflicted is NOT a consideration.
I build my own ARs. It is very difficult to get barrels with the original twist rate of an M16. By original, I mean an M16A1. (it is also very difficult to get ahold of barrels of any twist rate today.) I have barrels of various twist rates. A faster twist rate will stabilize a heavier projectile, so it is needed for loads like a M885 or heavier. I also have loads that use 40 gr. projectiles, much lighter than a M193. What I am going for in a lighter projectile is a very high velocity for the purpose of penetration of body armor, not fragmentation. It is a different approach than green tip penetrators (M885). I picked that up from a guy I know who works for the Secret Service and buys his reloading supplies from the same gun shop that I do.