Complex sentence: The Mauser rifle was accepted by the Prussian government on December 2,1871, and was accepted for service until February 14,1872, after a requested design change to the safety lock.
Split into simpler sentences: The Mauser rifle was accepted by the Prussian government on December 2,1871, but was not accepted for service until February 14,1872. The delay was caused by the Prussian government requesting a design change to the safety lock.