New blaster build

Hey guys. I am looking to build a new blaster from scratch. was thinking of using the Hk416 receiver, or the new MK2 M4 metal receiver from hawkex. just wondering where everyone would go from there. with the M4 I cant seem to find a v2 gearbox that, butwith the HK416 I was thinking of going with the war-interest V2 gearbox from renegade blasters?

kinda need a bit of help with the whole thing if you can. from handguard attachments I would need to everything LOL.

Thanks heaps in advance.

Iā€™d hold off on your gearbox for the moment. I hear Hawkex have something locally engineered in the testing for their receivers.