There have been documented failures with the ALS holster (not the SLS) locking up as well. The difference is Safariland actually put out a press release about it rather than denying like the BLACKHAWK! propaganda machine.
Service Bulletin for ALS™ Holster Users
February 26, 2009
Safariland has been made aware of a situation where the Provo, UT Police Department experienced malfunctions while training with the 6360 ALS holster on the range.
The range in question is covered with approximately 4-6” deep, loose pea gravel. The drills used called for the officers to draw, go to a prone position and fire, roll from one side to another and fire, and finally spin into a supine position and fire.
While doing such drills on a surface as described above, substantial amounts of gravel entered the body of the holster.
Officers then holstered their weapons, and in some cases debris had lodged between the body of the holster, and the ALS mechanism causing sticky operation, and in some cases jamming when the recommended clearing drill described below was not performed.
The recommended course of action if you suspect large amounts of debris may have entered your empty holster is as follows; 1) make sure the holster is in a vertical position (stand or kneel). 2) Operate the ALS relates lever several times, satisfying yourself that the mechanism is free of debris and working properly. 3) Holster your weapon normally.
It should be noted that neither Provo PD nor Safariland has been able to duplicate this situation with a weapon in the holster.
Currently there are several hundred thousand of these holsters in service worldwide, and Safariland feels all users should be reminded to take care with regard to their weapon and holster in the event they find themselves in an environment where debris could enter the muzzle or other parts of their weapon as well as their holster.
2 different topics here, weapon in or weapon out. Obviously, if you fill an empty holster full of debris, you're going to have a hard time re-holstering. I meant packing stuff in there with a pistol inserted.