M4 AEG Mags (WIP)

A cornucopia of M4 AEG mid-caps with fuzzy skin.

Experimental mid-caps are designed to have the maximum capacity and printability. Compatibility mid-caps are optimized for wider compatibility, these need support for the feed lips and have slightly lower capacity. The BB track in the compatibility inserts have a looser tolerance.

Included are two fuzzy skin variants and three bottom plates to customize your magazine.

Required hardware - short, mid, std:

M3 hex nuts - 8X, 9X, 10X

M3 flat head, 14mm - 6X, 7X, 8X

M3 flat head, 10mm - 2X (depends on the bottom plate chose)

Mag Spring - Use mid-cap mag springs. I find 0.5mm x 5mm x 10mm rectangular springs to work fine as well. Super Feed Springs work are not recommended.

BB Catch Spring - 4-5mm outer diameter would work. I used a 4.75mm/9/32" springs for the BB holder.

Articulated double-stack follow - I have one included, it is EXCRUCIATINGLY frustrating to print, good luck. This follower is known to work once post processed. I have not tested other followers.

Print settings:

The inserts are designed for 0.2mm bottom layer, and 0.15mm layer height. All the other parts do not care about layer height.

Use 3 perimeters for durability. Any material will work as long it is well-tuned. Beware of creep which may cause issues in the future.

It is recommended that you compensate for material shrinkage when printing the experimental mags in ABS, PC, or Nylon. The shrinkage of PETG is small enough to ignore in my limited testing.

Supports:

The included follower needs support everywhere, set the threshold to 29 degrees or 61 degrees, whichever is steeper on your slicer, also enable “do not support bridges”. You will need to carefully remove everybit of support, and work the middle joint free for smooth operation. Patience is key with this part. This follower also works really well with normal mags.

Other than the follower, only the spring holder and the compatibility inserts need supports in the depicted areas:

None of the other parts need supports. The experimental inserts are made to be printable without supports.

Fuzzy Skin:

There are two fuzzy skin types: A (left) and B (right)

The modifier meshes are split into two sections so you can have different fuzzy skin settings across regions.

The short mag in the cover cover photo uses Type B Modifiers with 0.4mm point distance. Fuzzy kin thickness is 0.2mm for fron and back, and 0.4mm on the sides.

Note that the 3MFs included in “Experimental” come with Type B fuzzy skin, and those in “Compatibility” come with Type A fuzzy skin.

To apply them yourself, load the shell STP file then right click to load in the modifier mesh.

The CAD files need FreeCAD 1.0.X and may need the Fasteners workbench addon. Please forgive my CAD sins.

Assembly note:

Make sure to remove all supports and check that the follower joint pivots freely. The mag spring will be an absolute pain to install. I find that keep all the screws loose so you can wiggle the two halves makes things easier. You may also need to tap the insert to help the spring go in. Patience is key.

You may need to sacrifice a hundred BBs or so to break in this mag. Just load them in and unload them a half dozen times and you should be good. I wouldn't let BBs used to break in a mag through my AEG.