The short answer is no.  The holster sizes are designed around specific firearms ensuring a proper fit and smooth draw.  We do say the holsters are more size specific then firearm specific though.  The reason we say that is often one size holster will fit many firearms.  For example, our Lieutenant holster fits the Shield (9mm and .40), XDs 3.3, Sig 938, Glock 26/27 and 43, a Ruger LC9 and even a 2” revolver. In order to determine the correct size for your specific firearm we recommend visiting our website (and choose a Manufacturer and your specific model firearm from our “Choose Gun” page).   If your firearm is not listed please contact us by phone 888-661-5579, eMail, or through the website (and select “Holster Size Question” on the dropdown Subject Line to help expedite the request) so we can ensure you a proper fit.  When properly fitted the firearm should sit just below the waistline keeping it comfortable in the relaxed position while still leaving enough of the handle accessible during retrieval for a quick draw.