the handgun a mechanical blocking element is also provided adjacent the rear of the trigger guard that is biased into a first position to prevent rearward movement of the gun and a second position that allows for rearward movement of a gun when the blocking element is moved by pressure on a thumb or finger ledge application_number US 77071001 A description the present invention incorporates features of previous patents and co pending applications of one or both of the present inventions 1 the present holster employs the biasing apparatus of rogers et al 39 239 to force a handgun forwardly to position the ejection port of a semi automatic handgun against a stop in the holster once seated in this manner the gun cannot be withdrawn in a simple vertical manner rather the gun must be forced rearwardly against the biasing means to remove it from the stop means in the present invention the stop means has been improved to make it removable in the event it becomes worn down so that a new stop means may be inserted in addition the stop means is replaceable by another stop means more appropriate to the handgun being used in the present invention the stop means is specifically designed to work with a glock handgun if the holster is to be used with another type of handgun the stop means can be easily replaced with one that provides a better match for the.