DeAR22

Overview

Dive into the future of AR-22 builds with the DeAR22 (Dedicated AR-22), a groundbreaking downloadable file that introduces the world's first truly dedicated AR-22 lower with functional last round bolt hold open (LRBHO). This innovative design is a game-changer for firearms and 3D printing enthusiasts looking to craft a reliable, modular .22LR platform with unmatched compatibility and performance.

The DeAR22 package is engineered to provide seamless integration with standard AR-pattern components while offering specialized .22-sized magazines and enhanced features like LRBHO. Whether you're upgrading an existing build or starting fresh, this design ensures precision, durability, and customization. It's a must-have for anyone passionate about AR-22 projects and cutting-edge 3D-printed firearm components.

DeAR22 Features

The DeAR22 stands out with its revolutionary LRBHO functionality, a feature that ensures the bolt stays open after the last round, enhancing usability and reload efficiency. This design is tailored specifically for .22LR, offering properly sized ScARpion magazines with 15 and 20-round capacities, fully compatible with standard AR mag catches.

Key highlights include:

Two Lower Options: Choose between the DeAR22-1913 with an integrated 1913 rail or the DeAR22-B with standard buffer threads for versatile stock and brace setups.
SGAR22K Upper Receiver: A reinforced mashup of AR22K and SG22K designs, featuring a stronger charging rod and compatibility improvements.
Modular Compatibility: Retains standard AR-pattern parts compatibility, allowing use with any dedicated .22 or conversion upper with a CMMG-style BCG.
1913 Stock/Brace/Sling QD Adapter: Adjustable and compatible with DeAR22-B lowers, ensuring a secure fit for various configurations.

This design prioritizes both functionality and customization, making it ideal for hobbyists and serious builders alike.

Difficulty & Build Time

Skill Level: Intermediate
Estimated Build Time: 12-16 hours
Required Experience: Familiarity with 3D printing, AR platform assembly, and basic firearm hardware installation

Hardware and Tools Required

Required Hardware

Any dedicated .22 or conversion upper with a CMMG-style BCG (or use included SGAR22K Upper)
Catch22 V1 Bolt Catch (essential for LRBHO function)
Catch22 Lightened Bolt Catch Spring (recommended for reliability)
Standard AR Fire Control Group (FCG) and Lower Parts Kit (LPK)
Mag springs (round or Z springs, per README)
For DeAR22-B: Buffer tube or end cap plug/adapter (or use included 1913 Stock Adapter)
For SGAR22K Upper: 1x Screw (#6, #8, or M4, max 1"/25mm)
For Stock/Brace/Sling QD Adapter: 6mm x 1.0 x 20mm Hex Screw (head diameter ≤10mm), 6mm x 1.0 Hex Nut (10mm wide)

Recommended Tools

Short 1/8" Hex Key (for SGAR22K Upper)
Hex Key compatible with 6mm Hex Screw (for Stock Adapter)
10mm Hex Key (for Hex Nut)
Standard tools for AR assembly (punches, hammers, etc.)
3D printer for printing components

DeAR22 Parts

The DeAR22 package includes a comprehensive set of STL files for creating a fully functional AR-22 lower and associated components. Included are the DeAR22-1913 Lower with an integrated 1913 rail, the DeAR22-B Lower with buffer threads, updated ScARpion Mags (15 & 20 Rd) with LRBHO functionality, LRBHO-Activating Followers & Mag Lock Plates, the SGAR22K Upper Receiver, and a 1913 Stock/Brace/Sling QD Adapter. These files are designed for durability and precision when printed with the right settings.

For optimal results, print using PETG or ABS for strength, especially for high-stress components like the lowers and magazines. Orient the mag bodies as recommended in v1.21 for stronger feed lips, and ensure proper layer adhesion by using a 0.2mm layer height with at least 4 walls and 20% infill. Refer to the included README v1.3 for detailed printing tips and assembly instructions.

Printer Compatibility & Settings

The DeAR22 files are compatible with most FDM 3D printers capable of handling detailed firearm components, such as Ender 3, Prusa i3, or similar models with a build volume of at least 220x220x250mm. Recommended materials include PETG for a balance of strength and flexibility or ABS for higher durability under stress. Avoid PLA due to its brittleness and low heat resistance.

Use a 0.2-0.3mm layer height, 4-6 walls, and 20-30% infill for structural integrity. A heated bed (60-80°C for PETG, 100-110°C for ABS) and proper cooling are crucial to prevent warping. Ensure your printer is well-calibrated for tight tolerances, especially for parts like the safety selector and takedown pin holes updated in v1.2 and v1.3.

Conclusion

The DeAR22 (Dedicated AR-22) offers an unparalleled blend of innovation and compatibility, making it a top choice for 3D printing and firearms enthusiasts seeking a reliable .22LR platform. With features like LRBHO, modular design, and robust components, this downloadable file empowers builders to create a custom AR-22 with ease. Dive into the public beta testing via the Matrix channel for community feedback