Hey everyone... I'm new to handguns.. about to get my first one.. "when I can settle on a dealer and price" I'm interested in the XDM 9mm in OD and I have a dealer selling one for $639.00 but it takes about an hour and 20 to get there. Then I have a dealer who is selling one 14 mins away but selling for $660.00.. Now I wont quibble over $21.00 but the dealer selling the one for $660.00 keeps saying something about making sure the other dealer is offering an "internal lock". Now I understand that on the XDM's you have to have both components compressed.. trigger and hand gripped.. but what is this internal lock she keeps speaking of? I did see a forum where someone was complaining about a S&W with an internal lock that kept prohibiting the gun from firing unintentionally... Thanks in advance for anyone who can help..