Why would they not have water? Europe has a major river every 50 miles or so and small streams and such all over the place.
Infact the British issued a small funnel at unit level to clean rifles with boiled water.
OK here it is AGAIN.
Every bore has microscopic pits in it though they might not be visible. Firing corrosive primed ammo drives the primer salts into those pits. A funnel and boiling hot water down the bore expands the pits and washes out the salts.
That is why the brits had armourers funnels that you stuck in the arse end of the barrel. They started using those funnels before 1900 and up untill the time they switched to Non corrosive primers.
Dating myself, but I was issued an M1. After a day at the range, we field stripped the rifle, took it into the latrine, and poured HOT water down the bore for the SAME reason, then cleaned it with patches and the usual gunk
They speak the truth. I bought this one through an ad in Can. Access to Firearms many years ago, as a collector piece to go with my LE.
But its so useful for actually cleaning corrosive, that I keep it with my cleaning kit.
I believe it is Canadian issued, so not just limited to British armourers.
I got the kettle from a garage sale for $3. The OD can on the right is US made bore cleaner specifically for corrosive ammo.
My cleaning program now takes less than 10 minutes.
Boil water, while water is heating I get the funnel and bore cleaner and a cleaning rod ready. Strip gun down, depending on gas system.
Pour BOILING water down funnel into bore and out into a bucket. Small parts like gas piston are in the bucket already.
Let gun bore dry out (hold muzzle down so no water trickles into the action) (Barrel is HOT to the touch, so it will dry fast)
Pour out water bucket, dry small parts.
Dip bore mop in bore cleaner (this stuff stinks like hell! Dont do this at the kitchen table!) and wipe through barrel.
Reassemble gun. Done