Not a good idea. The Threepersons is essentially the old Lawrence #120 Keith holster. It could be used either with or without retaining strap; however, the snapped strap is slow and uncertain. If the strap is not used, the gun is too loose in the holster. I used one with a M28 S&W in plainclothes for a while and it just didn't make sense. Also used some other combinations, some of which I would prefer to forget. What you want in plainclothes is a holster that combines concealment, a fair degree of security, speed, and all day comfort. For my last 15 years (all of it as a plainclothes officer--and a firearms instructor) I used a K frame 4" in a Milt Sparks #200AW holster (Hank Sloan Special) with great satisfaction. I still use it. It met all the above requirements very well, and I would still recommend it.
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