This started out as a weldable sumac upper(the sendcutsumac), that incorporated the magwell into the upper assembly, and has since expanded into a collection of weldable, and bendable mac 11 uppers in both sumac and DBAlloy styles.
Everyone likes to remix the mac lower but I never really see anyone putting files out to remix the mac upper itself.

This isn't a full DIY mac build, just a starting point to make custom uppers. you will need to purchase preexisting mac parts. you need a trunnion, bolt, and barrel from velocity firearms or other alternative vendors. as well as an ar15 fcg to finish this build.
One of the benefits of making a custom upper allows you to accommodate more room for FRT/Super Safety trip sleds.

It requires welding, the use of drill presses, angle grinders, center taps, shop presses, and a bunch of other tooling and skills.

Included in this pack is a DXF file for a Sheetmetal FRT trip.
This trip works with my DIY Sheetmetal FRT, and should work with other standard FRT designs like raregreed.

To use the trip you will need to modify the trunnion or the barrel so keep that in mind.

LBRY Tags: guncad; mac11; diy; 3d printed; frt