I have a 2008 dated GP100 4" barrel. Reading various sites it says 4.2 inch barrel is standard. If I measure from the barrel throat to end of barrel my Stainless Steel pistol measures exactly 4" long. Not a critical question, just curious. Just installed a set of Wooden grip from Thailand (very nice for the price) and really dress up the pistol. Tring to make it a little more Concealed carry capable. The Hogue rubber grip felt nice while shooting, but was a bit too sticky for carry. Will see how the new ones do.