Nerf Caliburn U - Simplified Edition

CHANGE NOTE 08/29/20 - Coupler, Frontbutt, and Backbutt revised to accept cosmetic stock spacers

CHANGE NOTE 05/01/20 - Improved ease-of-install for all hex standoff features.

CHANGE NOTE 04/15/20 - Merged MagBack and Pcap prints with modeled supports.

CHANGE NOTE 03/06/20 - Updated rail segments with anti-rotation keys (credit Thanhtacles), matching features on muzzle and magfront, and many small changes to coupler, frontbutt, backbutt, and buttplate.

CHANGE NOTE 12/21/19 - Replaced the lock nuts with 4-40 hex standoffs. All related parts updated.

CHANGE NOTE 12/7/19 - Added optional retrograde grip print.

CHANGE NOTE 12/7/19 - Vital changes to Coupler, Frontbutt, Backbutt, and Buttplate. Reprint highly recommended.

CHANGE NOTE 11/30/19 - Added optional takedown functionality.

CHANGE NOTE 11/21/19 - Updated hardware retaining features in most parts, added printable AR pistol grips, one with Caliburn features to accept grip inserts, added railgasm segments, added widened AFG.

This was an experiment in building a simplified Caliburn assembly without threaded rod.

Features

1. Top-loading of the magazine
2. Removal-Insertion of the magazine with the breech closed
3. All-Metal assembly with nested hex nuts
4. No twist/flex
5. U-channel provides alignment of all components during assembly
6. 20% Lighter in total weight
7. 30% shorter total print time

U-channels are made from 3/8" x 3/4" x 1/8" thick aluminum.
Majority of the assembly involves 4-40 x 3/8" length flat head screws and 4-40 nylon-insert lock nuts. All other hardware items except the AR15 pistol grip are standard Caliburn hardware items.

Hardware kits
https://outofdarts.com/collections/captain-slug
https://silverfoxindustries.shop/collections/hardware

Assembly Instructions: http://captainslug.com/nerf/CaliburnUAssembly1.pdf