Have you ever read this:
http://www.ft-designs.com/takingstock.htmlSome interesting stuff in there.
I spend alot of time figuring out what is comfortable in an airgun. Really depends on a few things, like what sort of gun? You shooting off a bench, or carrying it through the woods for offhand shots? The above article also talks about the law of averages, are you building for a specific person, or just coming up with a good all around design?
When I did the Talon pistol stocks I tried to address certain issues specific to that gun, like high comb(bottle) means that the shooters arms come at the grip from a much different angle than a standard rifle, not to mention a standard pistol grip. I tried to make the grip on those with the same angles to accomodate where the arms/hands naturaly rest. I like to shoot with my fore hand close to the trigger gaurd where the gun balances, so I cupped that area of many of my fore ends. Unfortunately I couldn't do anything about the bottle/high comb, but I did try to move the bottle up on the shoulder and less in the armpit so the shooters head would be more up and down rather than leaned over the top of the bottle.
Like I said, I think alot of it depends on the gun, and alot depends on the type of shooting you are making it for. If you are laying across a bench while shooting you want a more upright grip angle, flat bottom fore end and the buttplate right in the crook of your armpit and in a more linear direction to the rest of the gun. Off hand you might want the buttpad down lower to push the gun up more to help make it sit naturally rather than having to be held up all of the time. Think about how you shoot, think about what type of stock you are trying to make(bench, sporter, 3 pos, FT, 10M) and then look all over the web at pictures of other peoples stocks for the same purpose. Not all of the designs you'll find are going to be good, but you'll definately see a trend between models of what works and keeps getting incorporated into everybodies designs. Not to say there isn't things left out there to be an inovator of, just saying that alot of the key ergonomic features have already been figured out..like round wheels.
Good luck!
