It wasn't a manufacturing facility challenge for that model. Potentially creative crafting of a standard inventory. Photos would support to find out the appx yr your rifle was produced. 44 It was offered from about 1959-1963. One more defining attribute of the JTSS is it came using a Winchester 93B https://highimpactrounds.com/product/winchester-defender-12-ga-2-75in-1-oz-rifled-slug-00-buck-1150-fps-10-rd-box/