I agree with themauserkid as to the dating of the rifle to the early 1920s. It is certainly built on a reworked Gewehr 98 large ring Mauser action left over from the 1915 – 17 “decentralised” Gew 98 infantry rifle production in Suhl. It was retailed by BRAUN & MÜNZEL, Bahnhofstr., Coblenz. As the spelling of Coblenz was changed to Koblenz in 1926, the rifle was most likely sold before. A forgotten quirk of history: Post-WW1 Coblenz was occupied by the US Army until 1922. So the rifle may have been bought by a GI for a few -precious in Germany then- US$$. I know about a drilling sold by B&M too at the same time. The now American owner did not believe the family tale that his grandfather, a WW1 veteran, brought it as a souvenir from Germany, as the Americans did not “liberate” guns then. So this rifle too may have been bought new in Germany and brought to he USA in the 1920s. A further hint: The rifle retains it's original 1920s scope, usually lost on guns liberated post-WW2.
I see no hint to Simson or any other “name” Suhl gunmaker in the photos. Instead, I take the AH behind the serial number as the mark of Albert Heym, Rifle Factory, Hohe Roeder 7, Suhl, one of the many Heyms in the guntrade and a gunmaker to the trade. (Not to be confused with F.W. Heym, the namesake still in business)
The rifle was proofed in Suhl for use of the old pre-WW1 9x57 brush load, a 280 gr steel jacket bullet at 1916 fps.