SATX:
Have used it for over a year. Such cleaning with Windex followed by drying, once home, has left both bores of my MN 44s still as shiny as when they were bought. This includes having been exposed to fairly high Memphis spring/summer humidity for over an hour at numerous times during shooting/driving back.
The cheap new Remington .22 LR has caused gas blowbacks sometimes once in every five rounds in the old Savage.
With this old Bulgarian ammo, only once in over 700 rds, and it was mild. Just wear shooting glasses, but these guns are rugged.