There has been a great deal of improvement in steels, whether they be ordinary soft steels or various forms of nickel steel. No attempt with be made here to describe steels, as the subject would require and entire book. Thirty years ago, very little was known about heat treatment..
If you had a Winchester Model 1892 manufactured in 1905 and an identical model manufactured in 1935, assuming the original gun to be in perfect condition inside and out, you might place them side by side and notice absolutely no difference at first glance. Careful study, however, will reveal that the later gun is manufactured better, with a minimum of tolerance, slap, looseness or whatever you may choose to call it. That, however, is the minor part of the of the whole thing. There will be little laboratory resemblance between the material of which the two gun are manufactured. Changes and improvements are being made constantly, and where changes in the quality of steel or the strengthening of certain parts through heat treatment are made, the factory rarely, if ever, makes any announcement. If these same Model 92 rifles were fired with a Magnum .38/40 load, it is quite possible that the earlier gun might go to pieces, while the later one would be perfectly safe. These facts must always be considered in handloading.
Complete Guide to Handloading by Philip B Sharpe. First Edition 1937, Chapter XXX, Magnum Handgun and Rifle Possibilities. Mr Sharpe was born in 1903, died 1961.
If I'm not shooting, I'm reloading.