Maybe it didn't matter to Savage whether the 99's were called 1899's or 99's, for example, the receiver rings stamped 1899 until 1926.
That's my opinion. Since there had never been a model 1899F catalogued by Savage up to 1921, nobody at Savage was going to be confused if you called it an 1899F or a 99F.
Maybe Murray extrapolated this designation back to cover all rifles made from 1899 on.
I think this mishmash of 1899 versus 99 and 1899 stamps is why Murray has the 99 models starting at different serial numbers. Remember he researched and wrote his book before the internet, MUCH harder to find information out there back then. He did an outstanding job and made our job so much easier than it would be otherwise, it's just that in 30 years more data has come to light.
Heck, we're still trying to figure out the MP stamps.
Take it with a grain of salt I guess, for rifles of this time period.
I offered up #221xxx as a newbie, crescent butt, 26" rnd, T/D. Some forum banter occured, 1899 vs. 99, etc.
I got schooled by a member that what mattered is what the ledgers say.
So I requested a factory letter and it came back as 1899B and I reported it here.
Next I am informed by another forum member that the factory letter was wrong.
Pass the salt please,.....
Ledger may say 1899B... since Savage used 1899 AND 99 in their literature for the first couple years in the 20's. But the rifle would be what "we" and all the books on 99's call a 99B, and in all aspects would be exactly the same as a rifle in the ledger a year or two later that said 99B. But try to sell it to another collector as an 1899B and it probably wouldn't go well.
I'd describe it as "factory letter called it a model 1899B, but it's what all the books call a 99B".
This talk on "transition" rifles dates back a loooooong time. And will continue. I'm probably the only one who's totally made up their mind.
