The left just has to be apoplectic not being able to screech about the shooting as done by an alt-rightist white nationalist/supremacist using a scary black AR-45 full semi-auto machine gun with a silencer.
Most 1911 style .45s are 7-8 capacity but Glock and other plastic gun makers offer double the capacity. Some traditional 1911 makers (Para, Kimber for example) offer double stack weapons as well.
As a side note, how many would have died had coworkers been armed or would he have even attempted this mass shooting?