Guys,
If you get a chance check out a holster maker called Patriot concealment systems.com... They are also on Facebook under Patriot holsters. I use their Glock 21 inside the pants holster everyday and come to find out, lucky me they fit my brand new Glock 40 10mm long slide. It's kind of a big gun to put inside the pants but it does fit the holster perfectly. the barrel sticks out about 2 inches below it. It's good to have holsters at work for several guns. Nice secure fit,cool carbon fiber look. Great guys to deal with...as far as inside the pants/concealed carry, they are hard to beat. You can draw and reholster one handed,something you can't do with leather. These guys rock.
Link for the lazy:
http://www.patriotconcealmentsystems.com/category-s/1824.htm