Re: Do you have an Enfield etc, to avoid excess. wear?
Pretty hard to imagine "excessive wear" on an Enfield. If you had a minty Enfield, or any other historicaly signfificant weapon, I'd put it aside and let the collector value grow. But a run-of-the-mill military rifle is built to be fired LOTS. Just keep them CLEAN and take care of those corrosive salts and you'll be just fine.
I have a 1916 mfg Enfield .303. It has been fired plenty. The bore was more than just a 'tad' rough when I bought it, so I fire-lapped it with bullets from Brownell's. Much better now. It was pretty dang dark. Still a little pitted, but a fine shooter for a .303. Good quality surplus .303 is almost dried up.
Gotta agree with Oscarmeyer - the No.5 is lighter than the standard rifle, and they recoil harder. You do risk a cracked stock with full-patch loads with that old wood. You run the same risk shooting any old firearm.