Description from PSA's website:
"This Complete Palmetto State Armory lower is fully assembled and ready for your complete Upper!
Machined from Aluminum Forgings 7075-T6
Hardcoat Anodizing: MIL-A-8625F, Type III, Class 2
Milspec diameter Receiver Extension
Staked M4 Lock Nut
Standard Carbine Buffer
Un-notched Hammer compatible with 9mm use
What is the meaning of the above bolded? I've often thought of building a 9mm AR, but know little about the components or process.