Not shotgunners particularly, but I liked Ken Waters and do like John Barsness a lot for their American plain style and writing pretty much at my (not very elevated) level of technical understanding.
In the shotgun world I miss Wallace Zabrisky.
I like Steven Bodio for his ability to communicate his love for gun sports and the outdoors, and even the mania of falconers. Gives me a whole new outlook on the "natural hunters" that hunt along with us when we're out in the field. (Although I'm still sore about a sharpshinned hawk that stole a quail from me in the Snake River Breaks once....and a horned owl that stole my watch cap when I was working a rabbit squeaker for 'yotes!).
