The solution I found to this problem was to just go and start trying my gun in hoslters. I ended up with a Blackhawk IWB leather holster for a full size XD that fit my compact S&W M&P 9C. It ended up being one of the more comfortable holsters I own. The other thing you can try is just to go to a manufacturers website and contact them with your gun info and they will give you a list of " Will Fits" . Hope this helps!
"We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm." ---George Orwell on a BBC broadcast, April 4, 1942.