The trick to getting this to work right is to have the screw as countersunk in as possible so that the locking nub engages and doesn't disengage/push out. You might be able to find this clip in other styles, this clip doesn't seem to be a original design. There's one with a "release button" that is low profile so it's not oversized enough to potentially pop open when say leaning.
Just an FYI, You need to put the radio into the clip upside down and push until it clicks then swivel it into the upright position,
this should keep the unit secure. I'm not sure if this is how you are using it or not so I'm just putting it out there.
Mc48 was right. I did have the belt clip installed wrong. It works much better now. I haven't ruled out using a different method for a belt clip. Everyone gave me good advice and I appreciate it. Special thanks to mc48.
I bought a used 436HP and it didn't come with the belt clip... I saw this post & just ordered the Arkon Universal Swivel Belt Clip Holder on Amazon and should get it in a few days.
Not too sure about using the double sided tape and would love to use a screw to be more secure. Does anyone know the size of the screw to be used? Would hate to strip the hole or use a screw too long... Thanks