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Sylvan Arms AR-15 Conversion Block FITS Glock - SKU: GCB100 - UPC: 852237007907
Product Description
The Sylvan Arms AR-15 to 9mm Glock Magazine Conversion Block (GCB100) is an economical, high-performance adapter designed to convert standard MIL-SPEC 5.56/.223 AR-15 lower receivers into 9mm pistol-caliber carbines (PCC) using 9mm Glock® magazines. Engineered by Sylvan Arms, this bottom-loading magwell adapter allows shooters to run common double-stack 9mm Glock magazines (G17/G19) without purchasing a dedicated PCC lower receiver.
Precision-machined from 6061-T6 aircraft-grade aluminum with a durable matte black hardcoat anodized finish, the GCB100 features an integrated steel ejector, feed ramp, and last-round bolt hold-open (LRBHO) mechanism. The unit installs easily through the bottom of the lower receiver magwell and secures firmly using top and side tension adjustment screws to eliminate wobble and guarantee smooth, reliable cartridge feeding into 9mm upper receivers.
Equipped with a built-in paddle magazine release lever located beneath the magwell, the Sylvan Arms Conversion Block provides intuitive, fast magazine changes while maintaining a clean, low-profile footprint for competitive PCC shooting and recreational range staging.
*Armorer Bench Notes & Real-World Staging Guidance:
Fitment Matrix: Fits standard MIL-SPEC AR-15 5.56/.223 lower receivers. Accepts standard 9mm double-stack Glock pattern magazines (Glock OEM, Magpul PMAG GL9, ETS). Requires a 9mm AR-15 upper receiver, 9mm barrel, and 9mm bolt carrier group (Glock-cut BCG).
- Verify host AR-15 lower receiver is completely clear, magazine removed, and upper receiver removed from the lower.
- Insert the GCB100 conversion block upward through the bottom opening of the lower receiver magwell until properly seated.
- Tighten the internal expansion tension screws using the included Allen wrench to secure the block firmly inside the magwell without movement.
- Install your 9mm upper receiver assembly and cycle dummy 9mm rounds to check feed ramp clearance, ejector position, and magazine seating.
- Perform complete bench dry-fire and function tests, verifying last-round bolt hold-open engagement before live-fire range use.
Key Features
- Universal AR-15 Magwell Conversion: Converts standard 5.56/.223 lower receivers to accept 9mm Glock pattern magazines.
- 6061-T6 Aircraft Aluminum Construction: Lightweight, high-strength aluminum body with an anodized protective finish.
- Integrated Steel Ejector & Feed Ramp: Built-in steel geometry channels rounds smoothly and provides crisp casing ejection.
- Built-In Last Round Bolt Hold-Open (LRBHO): Retains functional bolt catch hold-open capability on the last shot fired.
- Bottom-Loading Drop-In Design: Easy installation from the bottom of the magwell with adjustable tension screws to ensure zero wobble.
- Paddle Magazine Release: Ergonomic paddle-style mag release allows smooth, rapid magazine swaps under time constraints.
Product Specifications
- Brand: Sylvan Arms
- MPN: GCB100
- SKU: GCB100
- UPC: 852237007907
- Platform Compatibility: MIL-SPEC AR-15 Lower Receivers
- Caliber Compatibility: 9mm Luger (9x19mm)
- Magazine Compatibility: Standard 9mm Glock Pattern Magazines
- Material: 6061-T6 Billet Aluminum / Steel Ejector
- Finish/Color: Matte Black Hardcoat Anodized
