The weak side hand placement operates and not using a Specific thumb rest. Thumb rest from Ronni is effective on MCK if you want. Shoulder strap attaches on both. No pistol brace extension necessary. MCK employs pistol's slide release so no mal-functions like Ronni. The one thing the Ronni has https://glockrecoverkit75174.timeblog.net/61707744/examine-this-report-on-recover-tactical-20-20