Books are excellent things to read often have interesting data. This is a book I recommend: Rifle & Carbine 98: M98 Firearms of the German Army from 1898 to 1918 Dieter Storz
Inside Dieter’s book are the material specifications for the M98 Mauser.
The material looks to be a manganese steel alloy, with copper added for easy machining.
I assume the material is in the normalized state, but the property requirements were Ultimate 78.2 Ksi, Yield 36.9 KSI, elongation 15%.
Carbon LT 0.40%
Manganese LT 0.90%
Copper LT 0.18%
Silicon LT 0.30%
Phosphorous LT 0.04%
Sulphur LT 0.06%
What he mentions in terms of manufacturing shows primitive process controls and that parts broke: Amberg Arsenal, retort ovens used till 1905, temperature judged by eye. Amberg M98 bolt lugs broke at the rate of 1:1000 rifles. The third lug was needed or bolt blowout would have caused injuries.
The 1888 series or rifles was about two generations earlier than the M98 and the metal in them would be even more suspect.
Those who are ignorant of the rapid progress in metallurgy, process controls, just assume, out of ignorance, that the steel in early rifles is as good as today. This is not so, but given that the natural state of humanity is ignorance, what can you do?
If I'm not shooting, I'm reloading.