I used Bullseye for most all of my target loads from the mid-60's til I ran out one time and tried a single pound of Win 231 on a trial basis...mid-90's as I recall and have used it ever since. I load for all the major hand gun cartridges ( .380, .38 Super, 9mm, .40 S&W, .41 Magnum, .44 Spl. & Magnum, and .45 ACP & AR) as well as some of the more obscure: .455 Webley, .32 Short, and .38-40 to name a few.
231 is Winchester's answer to Bullseye and is better suited for all of my mild to medium loads. It runs much easier through my Dillon and RCBS Uniflow measures as an added benefit. If I were forced to choose a single handgun powder and didn't need to push the upper velocity limits, Win231 would be the choice.
Even in the bigger cases: .45 Colt, .44 Special and Magnum, .44 & .38-40, it's produced accurate loads, ie. 2" or less at 25 yds from a rested position. It's every bit as tolerant of large volume cases and positioning as Bullseye ever was, and my Extreme Spreads prove it.
Best Regards, Rod