It is a Century build and the system is basic HK roller lock system.
I know Century has a lousy rep but the kits alone were worth the price at $399 they are HK kits.
I just use a feeler gauge to check bolt gap.
Bolt gap should be .012 to .020 in.
There are 4 sizes of rollers that will make the thing work longer than you do if you use it everyday, and they are like $4 a set.