MAGAZINE ADAPTERS

The MAG-AD is the part that started Stern Defense: a magazine adapter, designed, machined and assembled in our factory, that drops into a mil-spec AR-15 magwell and lets the rifle feed pistol magazines, with last-round bolt hold-open built in. Pick the adapter by the magazines you want to run: the MAG-AD9 for Glock, the MAG-ADMP9&40/P320 for S&W M&P and SIG P320, the MAG-ADMP45 for M&P 45, and the MAG-ADB92 for Beretta 92.

Feature / Model MAG-AD9 (Glock) MAG-ADMP (M&P / P320) MAG-ADMP45 (M&P .45 ACP) MAG-ADB92 (Beretta 92)
Caliber 9mm / .40 S&W 9mm / .40 S&W .45 ACP 9mm
Magazine Type Glock S&W M&P / Sig P320 & P250 S&W M&P (.45 only) Beretta 92
Last Round Hold Open ✅ ✅ ✅ ✅
Compatible with Mil-Spec AR-15 Lower ✅ ✅ ✅ ✅
Bolt Compatibility Glock Cut Bolt Glock Cut Bolt Glock Cut Bolt Glock Cut Bolt
Buffer Requirement 5.4 oz or heavier (carbine spring) 5.4 oz or heavier (carbine spring) 11 oz or heavier (carbine spring) 5.4 oz or heavier (carbine spring)
Feed Ramp 4140 NiB Coated 4140 NiB Coated 4140 NiB Coated 4140 NiB Coated
Material 6061 T6 Aluminum 6061 T6 Aluminum 6061 T6 Aluminum 6061 T6 Aluminum
Finish Type III Hard Coat Anodized Type III Hard Coat Anodized Type III Hard Coat Anodized Type III Hard Coat Anodized
Made in the U.S.A. ✅ ✅ ✅ ✅
Special Notes Most versatile Sig 30-rd mag not compatible Requires enlarged .45ACP ejection port Only works with Beretta mags

The MAG-AD Flare MOD1 and MOD2 fit over the adapter, and the MAG-AD ejector replacement kit is the spare for an adapter that has seen a lot of rounds.

Two fit notes before you order. The adapters are designed for mil-spec AR-15 and M16 lowers; billet lowers with irregular magwell contours should be checked against the measurement on our compatibility page. And Glock 26 and 27 magazines are too short for the MAG-AD9, as are large-frame Glock .45 ACP and 10mm magazines, which do not fit a mil-spec lower at all.

Pair any adapter with a Stern upper in the matching caliber, or order both together as a conversion kit.