If you wish to scrub the bore, you really should pull the barrel from the pistol and yes, this requires removal of the bushing.

I can tell you that I shoot one of my 52's regularly and my process it to NOT scrub the bore (and this not remove the barrel/bushing) until I have something between 750-1000 rounds through it.

Instead, my usual process is an exterior wipe-down after a range trip and just before next range trip I will remove the slide (keep barrel in slide) and wipe clear the entire frame, frame rails and underside of slide and inside of slide rails and then generosly lube before putting the halves back together.

With pistol reassembled, I lock the slide open and wipe any visible filth from the inside accessible from the ejection port.

I'm no expert but my rationale is to find a balance amongst:
--getting filth out
--getting clean lube in
--not taking the bushing out more than necessary

This has been working quite well for me.