458 SOCOM Complete Upper Assembly. The 458 SOCOM Upper Assembly brought to you by Bishop Ammunition
Manufacturing is a complete ready to install upper assembly. There are no changes or
modifications required of any standard AR-15 Lower Assembly to install our upper assembly.
The 458 SOCOM uses standard GI magazines for 5.56 NATO/.223 Remington AR-15. Please
note that plastic magazines may not allow chambering of 458 SOCOM due to a ridge that is at
the center of the front of the magazine.