Thread: HXP 303 ammo corrosive? found rust in my barrel

The corrosive salts dissolve into the pores of the steel in the barrel. Hot water removes most of it, but not every last bit. You reactivate what is there on shooting even using modern ammo in old firearms, also primers even non corrosive still contain reactive products so in the right conditions any barrel will rust after shooting including stainless.

Boiling water out of a jug is the easiest way to strip salt from a barrel, then push through a patch to dewater and then clean as normal. Always chamber to muzzle if possible, push the crap out of the chamber not into it (not always possible). Use a guide for rods if you can, bronze brushes are good for stubborn fouling but use with powder solvent only as copper solvent will eat the brush and show as green on a patch. One piece rods, if coated wipe the rod every few passes to make sure it's decrapped.