Is there any reason you want a mechanical lock on your holster? The Bladetech DAA and Comptac type holsters work fine, I'm in nearly 20 years of IPSC never seen a holster come out of a properly adjusted friction bucket holster, not saying it doesn't happen ( lots of folks on here say it does) but I've never seen it at an IPSC match. And I've been an NROI and IROA RO for the majority of those 20 years.