Last evening, I compared my 422's. The six inch barrel was much, much smoother and quieter when racking the slide. So, I took the four inch barrel one apart, including the grips.
It IS possible to remove the guide rod retaining clip without moving the slide far enough to engage the slide lock. The guide rod block is approx. an inch long. About the length of a .22lr round, but do NOT use a live round as a block; the guide rod may ignite the primer if it slips. The block can be inserted when the slide is LESS than an inch to the rear because the fr. Then, the retaining clip can be removed; and the gun disassembled.
After running my mechanism thru a couple of cycles, cocking and recocking, everything now works OK. However, I can see I need to do a really through cleaning and lube job on the internals. I bought the gun used, did a quick cleaning and lube job. It needs more. At the same time, I'll file and polish everything that needs it. I had already done that for the six inch barrel 422.