What do you mean?
What I mean is so many K98k experts get their info from 20 to 40 year old books that have bad info . So much more info has come to light with all the Russian captures and records from behind the Com-bloc .
I've no idea.
However, as for books, he's probably talking about the Richard D Law books on the K98k which date to the early 90's and are often cited as the font of all knowledge on the K98k (especially here in UK as they were available here) but many things in these books have know been proved to be incorrect in light of new reference material and research, especially from information gathered from eastern Europe after the break up of the USSR.
A lot of this new and updated info has been published in the large 3 x volume books about Collecting the K98k written by Bruce Karem & Michael Steves. These were very expensive to order from outside the UK, because of the shipping costs from USA due to the weight, (I bought Vol's I & II a few years ago) so many in the UK still cite the Law books for info...including a few well known RFD's that don't like being told the info they post in their adverts for rifles is not correct!!!!
Volumes 1 and III sold out some time ago, I think only the two parts of Vol II are still available, but they may now be sold out.
The info I posted was taken from Vol IIb of the Karem&Steves book, so I too am interested to know what is not correct.
I don't automatically assume that everything that I read in a book or posted on the internet is is always going to be 100% correct 100% of the time. One can write 100% pure B.S. which some assume must be 100% accurate information if it is seen posted online.
When in doubt, check the references in the article or book. Such references often provide astonishing new information, good or bad, not first apparent in the original text.
I like books, old or new, with plenty of photos and, as they say, a picture speaks a thousand words.