The Angstadt Arms UDP-9 SBR is a 9mm short-barreled rifle that ships with a 17-round Glock magazine and runs on Glock-pattern mags, built on billet receivers around a 6-inch barrel (brand part no. AAUDP09S06). The slick-side upper skips the forward assist and dust cover, which keeps the profile clean and the weight down. Radian Weapons supplies the ambidextrous Raptor LT charging handle and Talon safety selector, so the rifle runs from either shoulder. A 5.5-inch M-LOK handguard and a B5 Systems Bravo stock round out a package Angstadt Arms lists at 22 inches and under 5 pounds. It suits shooters who want a small 9mm rifle for home defense, training or a suppressed build.

Key Specifications

• Chambering is 9mm, which keeps practice affordable and recoil light.
• The action is straight blowback, a simple system with few parts to service.
• The barrel is 6-inch chrome moly with a black Melonite finish, which resists wear and corrosion.
• Rifling twist is 1:10, a rate that stabilizes the common 9mm bullet weights.
• The muzzle is threaded 1/2×28 with an Angstadt Arms A2-style flash suppressor, ready for a standard 9mm muzzle device.
• The lower receiver is 7075-T6 billet aluminum with a flared magwell, integrated trigger guard and last-round bolt hold open, which speeds reloads.
• The upper receiver is a 7075-T6 billet slick-side design with an appropriately sized ejection port and no forward assist or dust cover.
• The charging handle is a Radian Weapons Raptor LT ambidextrous model, usable from either side of the rifle.
• The trigger is an Angstadt Arms EMT-9, and the UDP-9 also accepts most aftermarket 9mm PCC triggers.
• The safety is a Radian Weapons Talon ambidextrous selector, so left-handed shooters get the same control.

Frequently Asked Questions

How compact is the UDP-9 SBR? Angstadt Arms lists it at 22 inches long and under 5 pounds, small enough for a vehicle or a tight hallway.

Do I need ATF approval to buy this? No. As of October 9, 2026, ATF no longer requires Form 4 approval, registration or a tax stamp for short-barreled rifles. It transfers on a Form 4473 with a background check through a Class 3 (SOT) dealer. State and local laws still apply. Taking an SBR across state lines still requires an approved ATF Form 5320.20.

Does it come with a magazine? Yes. One 17-round Glock magazine is included, and the rifle accepts Glock aftermarket magazines, although Angstadt Arms recommends factory Glock magazines.

Buy the Angstadt Arms UDP-9 SBR 9mm, 6-Inch, 17-Round Glock Magazine

As of October 9, 2026, this short-barreled rifle transfers on a Form 4473 with a background check at your Class 3 (SOT) dealer, with no Form 4 or tax stamp; state and local laws still apply. Order through Angstadt Arms‘s short-barreled rifles lineup and our Lubbock, Texas team will handle the transfer, and it ships fast to your Class 3 dealer. The UDP-9 trades carbine length for pistol-like handling and keeps a stock for control.