Complex sentence: It uses what is basically a.308 cartridge case necked-down to accept a.244 in/6 mm bullet, and the.243 is well known for its accuracy, very flat trajectory and relatively mild recoil compared to other deer cartridges.
Split into simpler sentences: It uses what is basically a.308 cartridge case necked-down to accept a.244 in/6 mm bullet. The.243 is well known for its accuracy, very flat trajectory and relatively mild recoil compared to other deer cartridges.