In this case, it was because the bolt handle on the m1889 worked just as good on the K-31. While the Sig 510 doesn’t require you to pull the bolt each time you

In this case, it was because the bolt handle on the m1889 worked just as good on the K-31. While the Sig 510 doesn’t require you to pull the bolt each time you fire, it did need a handle to grab to load the rifle - why create a new part with a new supply chain? After all, the older rifles were still in service for years after the new one was adopted, so re-using the same handle meant they only had to stock one part in their armories instead of two. Here’s the bold assembly for the Schmidt-Rubin 1889 or 1896/11: https://i.ebayimg.com/images/g/hqEAAOSwT~9WhutS/s-l300.jpg https://i.ebayimg.com/images/g/hqEAAOSwT~9WhutS/s-l300.jpg Here’s the bolt handle on the Schmidt-Rubin K-31: https://www.gunpartscorp.com/pub/products/997460.jpg https://www.gunpartscorp.com/pub/products/997460.jpg Here’s the charging handle on the Sig 510: http://i870.photobucket.com/albums/ab269/Combloc/SIG%20510-7/P1110558_zpsb5dd0b3e.jpg http://i870.photobucket.com/albums/ab269/Combloc/SIG%20510-7... The part you grip is interchangeable :)