I used nothing but Winchester 540 for years shooting 28 gauge skeet . This stuff was great , then at some point they saw fit to quit selling it anylonger . It’s my understanding HS-6 is the same thing , but don’t take my word for it check into it before using . Well read this it says it is the same thing !
https://www.hodgdonreloading.com/hodgdon/hodgdon-hs-6 Quoted from the above link , HS-6 is truly an outstanding spherical propellant and identical to Winchester's discontinued 540