Good gear...
I agree with part of the last post.
It may be smart to use a high quality LE trade-in or a sidearm a lot like what local LE agencies issue or carry.
Author, sworn LE officer & tactics instructor Massad Ayoob puts that advice out often to armed citizens/students.
As posted, a used pistol may get knocked around & banged up a lot on duty.
Years ago, I work on a mobile patrol position that by contract had sites that were armed & unarmed for uniformed security officers.
It was a #+=% to holster & re-holster constantly on duty.
I also worked briefly as an armed prisoner transportation officer(extraditions).
The armed, uniformed security officers had to sign their sidearms in/out constantly in state/local jails, prisons, detention cells, etc.
We once had to place all our firearms & weapons in a plastic bucket!
I'll close by saying the smart thing to carry in armed or unarmed security jobs is a good fixed or folding blade. A top brand like CRKT, Ernest Emerson, Benchmade, Gerber, Cold Steel, etc. Don't use cheap, mall ninja crap either.
Professional grade designs with glass breakers & seat belt cutters work best.
I kept a razor sharp Benchmade knife with me for approx 3yrs on security details. It will be useful & give you a "quiet professional" look.
ClydeFrog
PS: Please check any local-state laws re; knives, chemical agents, taser or energy weapons, ASPs, etc. Get formal documented skill training too before you carry any weapons or restraints(handcuffs) on any protective service site/job.