Assuming you’re starting with an MR762A1 with a heavy barrel, you’ll need the following:
RAL8000 Receiver Extension
Extended castle nut
Receiver Backplate with sling hook attachment
RAL8000 E1 Stock
RAL8000 anodized rear sight
RAL8000 Ejection port dust cover
RAL8000 wide loop trigger guard
RAL8000 Magazine Baseplate
RAL8000 selector levers
HK G28 Flashider
Eratac 24mm RAL8000 mount with 10 MOA cant
Schmidt & Bender PMII 1-8x24 RAL8000
HK G28 RAL8000 417/G28 Patrol Handguard
A factory steel upper receiver in RAL8000 and factory G28 gas block takes it to another level, as does using one of the factory G28Z guns that have made their way into the US. For clone builds, accuracy comes at a price, the more correct the details, the more it costs.