At one stage in my life, I owned two SMLE rifles, both in .303 British of course. One, a Lithgow, I had scoped for hunting or open F class competition. The other I kept in original condition save for (reversible) fitting of target rear peepsights. It was all about the application. I'd already had to re-stock the scoped one (first stock broke), so I didn't feel bad about altering it from the original, but the other was British, already pushing 100 years old, halfway round the world from home, and had almost certainly seen service in at least one world war and possibly both. No way I was getting that one drilled and tapped.