Buy a good set of gloves and protective eye wear. And while your in Home Hardware pick up small corks, two plastic flower planters, (long shallow kind), and a jug of muriatic acid.
Take the gun apart, and remove all grease. Put one cork in the end of the barrel and fill it with water. Squeeze the other cork in the other end, (I've only done 30 cal riles so I don't know if there are 22 cal ones - if not use modelling clay to seal barrel) Once the barrel seals are water tight, put on the gloves and glasses and gently place the gun parts in the acid in one of the flower planters. It should remove the bluing in seconds, maybe a minute or two tops.
Take the part out with a PAIR of LONG PLIERS and gently place in the other planter filled with water.
I've seen bluing come off in seconds and the longest has been 5 minutes or so.