According to "Mauser Bolt Rifles" by Ludwig Olsen, the M94 has a 17.71" barrel length with a 1 in 7.87" right hand twist. The M96 has a 29.10" barrel and 1 in 7.87" right hand twist. the M38 is a 23.6" barrel with a 1 in 7.87" right hand. I am not certain how accurate these rates are. I only referenced one book. Hope this helps out!
sixfive;
Good evening to you sir, I hope the day treated you acceptably and this finds you well.
Thanks for giving the OP the answer out of the Olsen book, it's a wonderful reference manual for sure on most all things Mauser.
If you're into Swedes in particular the book, "The Swedish Mauser Rifles" by Steve Kehaya and Joe Poyer is quite good too as well. Here's a link, though it is Amazon for which I apologize.
https://www.amazon.com/Swedish-Mauser-Rifles-Collectors-Only/dp/1882391268Here's an Abebooks link!
https://www.abebooks.com/book-search/title/swedish-mauser-rifles/author/steve-kehaya-joe-poyer/Lastly, our eldest daughter shoots a 1903 vintage Carl Gustav Swede and my walking around rifle is a between the wars commercial roll marked 98 Mauser that I had a smith fit a near new 96/38 barrel onto and both of them measure at 1:7.75" as close as I'm able to tell.
They are a deep groove barrel too and as such seem to really like monometal bullets if one wants that sort of thing for hunting.
Hopefully that helped as well. All the best to you all this fall.
Dwayne