The so-called Turkish Model 1954 ATF-marked Rifle, apparently rebuilt (circa 1954) from surplus WWI German Gewehr 98 rifles. Shortened receiver ring to make a hand guard holder. Stamped on receiver is an encircled ATF logo over 1954; left side of receiver is marked, "98.Th." on this example.
It is believed less than 10,000 of these were produced in this fashion.
Imported by Century Arms International and so marked on the barrel near muzzle. Century Arms has stamped on these "M38" indicating these were Model 1938 Mausers; my research indicates some people believe otherwise. Internal staggered box magazine, 5 rounds, 7.92 x 57 mm (8mm) Mauser caliber.
See also the Turkish Models of 1893, 1903, and the 1903/38.