This is a 50 yard OFFHAND(!) target I fired with my dumb little .50 cal 1:48", 26" barrel T/C New Englander I assembled from a kit (my favorite percussion rifle). Honestly, if I could duplicate this with my 1:66" custom flinter I'd be a happy, happy man. It will shoot this way from a kneeling or sitting position any time I ask. I haven't used a proper table "rest" in better than 15 years.
You'll never hear me badmouth the 1:48" twist, provided you take the time to find the load that works in your rifle. This is 84 gr FFg and works perfectly well on deer. Anything much heavier is all over the target. My .54 cal 1:48 Renegade seems to shoot well with anything on out to 100 yards, and for many years was my primary squirrel rifle with 42 gr FFg.