Nice shootin. I don't think you can do better with a scope. And if you could, how would you know? It'd be just one hole!
Hi-Lux/Leatherwood offers a Chinese made Malcolm type scope but from the reviews I've read they're of poor/inconsistent quality. Montana Vintage Arms makes a higher quality reproduction, however double the price but I would rather spend more money on something that works than a cheaper headache.
MVA scopes 
