Thread: CRC or WD40 for maintenance?

Yep. Nothing wrong with it for general cleaning and rust prevention.

Not that flash on copper or lead fouling though.

Both WD40 and CRC are good for cleaning. And they do leave some film behind after evaporating so better than nothing. To leave a more reliable protective oil film I wipe over with a rag lightly soaked in 4-in-1 oil.

Gun bluing does not protect much against rust unless it is oiled (bluing retains the oil in its "pores" and together they protect).

Carbon and/or copper fouling - I clean first with washing up detergent mix on pull-through rags. Then I wipe the muzzle and seal it up with electricians tape and point the rifle down. I pour a freshly mixed amount of citric acid + hydrogen peroxide into the barrel, leave 15mins (or until bubbling stops!), rinse well with water and then pull through wads/brush until they come out clean. Finally a rag with some 4-in-1. Not saying it's only or the best method but it does work. Be careful getting this solution onto unprotected (non-oiled) bluing.