This rifle is a Haenel Model 1909, grade St.P.Nr.6. A page from the contemporary Haenel catalog and a translation of the description:

Action and magazine of the cliploader system Haenel Model 1909 for carbines and hunting rifles
The lockwork cocks on opening. The firing pin is parted; it´s point is in the bolt head. Injury to the shooter, if in eventual de- and reassembly of the bolt putting back the bolt head is forgotten, is completely impossible. To cover the shooter from gas eventually blown back in shooting, a gas shield is mounted between cocking piece and firing pin nut.
The magazine holds 5 cartridges and may be loaded from top with an open bolt by stripper clip or without one; and just as easily it may be filled or replenished with single cartridges from the bottom, magazine cover open. The magazine cover is opened by pressure on a side-mounted pushbutton; the magazine may then be emptied by a single movement from below.
St.P.Nr.6 : Stripperclip loading hunting rifle Haenel system, Model 1909. Bolt with gas shield, bent bolt handle with pear shaped knob; Barrel Krupp´s cast steel, round; with bead foresight on short, matted base, standing rear sight with one small folding leaf, and double set trigger, better stock wood and better finish; halfstock with cheekpiece and checkered pistolgrip.