Just a few more words about personal experience and opinions.
One of my hunting buddies has in his collection a early 1900s Purdey, and a Beretta SO5, both 12 ga. They fit him, as does his 12 ga. M-21 field grade. He's carried them all for pheasant hunting over the years, but several years ago settled on the 21 as the best of them for his pheasant hunting -- which is like mine, walking lots of miles with one or two buddies behind flushing dogs. He's 64 years old, but with no fetish about gun weight as a necessarily primary criterion for good handling.
I'm 60. My own 16 ga. is a mite under 6-3/4 lbs. It's not light for a 16, but so what? The stock fits me, and it's one of the two best handling of my 7 side x sides, of various gauges and weight.
I agree that prices are very high -- maybe something to do with only 30 some thousand made?
Jay
