Mac22 mk1 official open beta release

designed by HulkHoganHH ([email protected], HulkHoganHH#2447)

previous versions floating around the internet are built for press fit pins, this version is built for metric socket head screws and bolts and has other improvements made

magazine is still pending final development

spring lengths in photos and .step assembly are not accurate and for reference only

extractor and feed ramp are built into magazine

required materials for manufacturing:

m2.5 nut x2
m2.5x16mm bolt x1 (for mag catch)
m2.5x30mm bolt x1 (firing pin)
m4 nut x1
m4x40mm bolt x1 (trigger pin)
4mm dowel pin, cut to length (sear pin)
M6 nut x4
m6x30mm bolt x1 (recommended length, for retaining bolt spring)
m6x40 bolt x2 (barrel lug pins)
m6x45 bolt x1 (mounting upper to lower)
.375" OD x .305" ID spring stock, cut to length (for magazine, bolt, between sear and trigger, for mag release)
cut to length spring with weight of your choice for trigger
6mm x 8mm steel tubing (barrel liner may also work)

mcmaster carr SKUs:
90592A080
91290A059
91290A106
90592A016
91502A170
91290A338
91290A336
9662K19
91290A184
90592A090

print all parts at 100% infill at the following orientations:
trigger, sear, mag catch, mag cap: on side
barrel lug, upper receiver: muzzle end down
bolt: face up
magazine, mag follower: facing upwards
receiver: optimal based on printer geometry

barrel liner should be epoxied into place
chase all holes with appropriate size drill if needed
top face of mag follower should be sanded to remove layer lines and resulting friction interference
heat stake trigger spring of your choice into position behind trigger
heat stake ~1/4" length of 3/8" spring into round pocket on sear
heat stake 1/2"-5/8" length of spring into mag release
sharpening of firing pin screw recommended