What does this stuff mean:
"UPPER RECEIVER: Mil-Spec with Indexing Marks and M4 Feed Ramps." - What are indexing marks and M4 feed ramps?
"Mid-length Gas System" and "Pinned Low Profile Gas Block CNC Machined of 4140 hardened steel and Mil-Spec Heavy Phosphate Coating, Mid-length, Direct Impingement" - what does all that mean? How does it compare to other options?
"BOLT CARRIER GROUP: M16 Profile, Mil-Spec MP Tested, Chrome Lined, Properly Staked Gas Key" - What other profiles are there and is the M16 profile better? Whats a propertly staked gas key?
Thanks
"UPPER RECEIVER: Mil-Spec with Indexing Marks and M4 Feed Ramps." - What are indexing marks and M4 feed ramps?
"Mid-length Gas System" and "Pinned Low Profile Gas Block CNC Machined of 4140 hardened steel and Mil-Spec Heavy Phosphate Coating, Mid-length, Direct Impingement" - what does all that mean? How does it compare to other options?
"BOLT CARRIER GROUP: M16 Profile, Mil-Spec MP Tested, Chrome Lined, Properly Staked Gas Key" - What other profiles are there and is the M16 profile better? Whats a propertly staked gas key?
Thanks