think I have two milestones again when dating Dreyse guns
remember that Franz v. Dreyse died in 1894 and the family sold the firm to Rheinmetall in 1901. I presume that the new Rheinmetall Sömmerda dont make sporting rifles anymore because the firm was bought for making artillery stuff for Rheinmetall. of course there were eceptions like the Dreyse selfloading carbine

what was more or less a by-product of the selflopading pistol 07

so the highest number of a Franz v. Dreyse marked gun is this
"A RARE SIDE-OPENING PATENT 12-BORE HAMMERLESS GUN BY F. von DREYSE (SMMERDA), NO. 33290

I assume that between 1894 and 1899 guns were marked only with " v. Dreyse Sömmerda"
in 1899 the Munitions&Waffenfabrik Sömmerda AG was founded where Heinrich Ehrhardt had more or less the control. here is a headstamp of a 5,6x33 with the M&W Soemmerda headstamp:

http://www.cartridgecollector.net/t55-57-x-33-dreyse

and whats with the serial numbers then?

MUN. & WAFFENFABR SOMMERDA
A 7.9mm BOLT-MAGAZINE SPORTING RIFLE, serial no. 37531 http://auctions.holtsauctioneers.com/asp...no=&image=0

number 37531 is made in the time of Munitions&Waffenfabrik Sömmerda AG between 1899 and 1901