If you think about it, The Krag system is only 10 years older than the 98 Mauser system. or by WWII it was only 50 years out of date. If you apply that logic to today, our soldiers would be carrying M-16's! Oh wait they are.
It isn't how old a system is, it is weather the system was any good in the first place! The 303 Brit, 30-40-US and 8x58R Krag are all good rimmed rounds of about equal power and performance! It was the American, James Paris Lee that came up with the better rimmed cartridge rifle. SMLE means Short Magazine LEE Enfield (Enfield denotes the type of riffling, early models had Medford style riffling for jacketed bullets with Black Powder)
The British war masters recognized the better action, but also had the brains to understand that if you want a single shot rifle, DON"T USE A MAGAZINE ACTION. For single shot rifles stick with a Martini! Here, the Krag and early 03 had cut off devises to limit them to single shot status. This was a very bad choice for an Infantry rifle in the dawning machine gun era! (The Navy and USMC adopted a Lee designed rifle [made by Colt] but Congress strangled the funding...if only, if only!)
By the way, families with a memory of hunts long ago, remember that 30-40 US was and is a great deer cartridge and a pretty good war cartridge too, the US, Danish, and Norwegian rifles fell into the deer category very well, but were so-so when it came to people hunting, at least if they were shooting back! The 30-40 Gatling guns were fantastic! (but Hotchkiss took the world to undreamed of perfection in mass killing!)
Ivan