AR-15 9mm – Glock Magazine Conversion Block – Mil-Spec Lower – Black
PLEASE DOUBLE CHECK DETAILS AND FITMENT BEFORE PURCHASE.
The Sylvan Arms conversion block gives you a drop-in path to run Glock-pattern 9mm magazines in a standard Mil-Spec AR-15 lower without buying a dedicated pistol-caliber lower. It is built from steel and 6061-T6 aluminum with a black anodized finish and is made for simple install and quick swap-out use.
This is a practical piece for guys building an AR9 off an existing lower instead of starting from scratch and spending money like they lost a bet.
Fitment
- Fits Mil-Spec AR-15 lower receivers
- Designed for 9mm AR builds using Glock-pattern 9mm magazines
- Requires a proper 9mm upper for function
Does NOT fit
- Does not convert a standard 5.56 upper to 9mm by itself
- Does not provide last round bolt hold-open functionality
- Do not assume fitment with non-Mil-Spec lowers
What it does
This block adapts a standard AR-15 lower to accept Glock-pattern 9mm magazines, letting you build or convert to a pistol-caliber setup without moving to a dedicated Glock-mag lower.
Why it’s worth it
It is a straightforward way to get into an AR9 build with less commitment and less parts chasing. If you already have a lower you trust, this keeps the project simple and flexible.
Specs
- Brand: Sylvan Arms
- RSR SKU: SYGCB100
- Product type: 9mm magazine conversion block
- Platform: AR-15 lower receiver
- Magazine pattern: Glock-pattern 9mm magazines
- Receiver fit: Mil-Spec AR-15 lowers
- Material: Steel and 6061-T6 aluminum
- Finish: Black anodized
- Weight: 4.2 oz
- Last round bolt hold-open: No
What’s included
- Sylvan Arms conversion block
Install notes
Install is intended to be simple and drop-in, but this is still a function-critical part. Use a proper 9mm upper and verify magazine lockup, feeding, and safe operation before live use.
Verify before you buy
Verify you are using a Mil-Spec AR-15 lower, a true 9mm upper, and Glock-pattern 9mm magazines. Also verify you do not need last round bolt hold-open, because this block does not provide it.
⚠ Glock Disclaimer
IronKells Armory LLC is not affiliated with, endorsed by, or sponsored by Glock, Inc. or Glock Ges.m.b.H.
All references to GLOCK® are used solely to identify firearm models, parts compatibility, and fitment information for customers. Glock is a federally registered trademark of Glock, Inc. and Glock Ges.m.b.H.
Any product sold on this site referencing Glock is aftermarket, not OEM, and is not manufactured by Glock. Glock does not warranty, authorize, or guarantee the performance, safety, or reliability of any third-party components or modifications.
Firearm parts should be installed by a qualified armorer or gunsmith. Improper installation, modification, or use of aftermarket components may affect firearm safety, reliability, and void manufacturer warranties. By purchasing and installing third-party parts, the buyer assumes all responsibility for safe handling, installation, function testing, and use of their firearm and accessories.
⚠ Install & Compatibility Disclaimer
Installation should be performed by a qualified armorer or gunsmith. Improper installation, modification, or use may affect firearm safety and reliability. Buyer is responsible for verifying compatibility, performing proper function testing, and ensuring safe operation.