Ammo, Corrosive or Not

[Bruce_in_Oz]

The "DA" headstamped stuff is WW2 Canadian, and is both Mercuric-primed and "corrosive". Quick guide; if the primer cups are copper-coloured, the primers will be Mercuric-based. The corrosive thing? Treat ALL ammo as corrosive until proven otherwise; then clean properly anyway.

The S&B uses Lead-based primers and MAY be corrosive.

As an Australian growing up expending a LOT of .303 ammo, ALL of which was corrosive AND mercuric, I was made well aware of proper cleaning at an early age.

Don't worry too much about the "mercuric" thing because that is only relevant to the reloading life of the brass. The chloride salts deposited by "corrosive" primers are what kills barrels.

Thorough cleaning, as soon as possible after firing, will keep your barrel in good shape. Leaving it for a couple of days may do some nasty things to the rifling. A basic "wipe through' at the range and a thorough job when you get home will keep the rust bugs at bay. Re-cleaning and oiling a few days later is also a good idea.

Just oiling it is not enough, as the salts are only water-soluble and will start to attack the barrel steel under the oil film.

If you have a LOT of the DA stuff and intend to do a fair bit of "rapid' shooting, your barrel may just get some accelerated throat erosion. That is because the original "Cordite' propellant burns VERY hot. It is not "bad" ammo, just "full of surprises" for the unwary.

In actual military systems, appropriate cleaning facilities and materials are provided and proper cleaning procedures are / were taught and enforced.. In "civilian" life? Not so much.

Timely and appropriate cleaning is a LOT cheaper than a replacement barrel.