Angstadt Arms UDP-556
Angstadt Arms · Pistol · In Production · 2017
Also known as: UDP-556, UDP556, SLK-15
Overview
The Angstadt Arms UDP-556 is a billet-aluminum AR-15 chambered in 5.56x45mm NATO, built on the same fully machined 7075-T6 receiver architecture as the company's AR-9 pistols. It is offered across 10.5-inch and 11.5-inch pistol/SBR configurations and a 16-inch non-NFA rifle, all with chrome moly Melonite barrels, 1/7 twist, 1/2x28 threading and an A2-style flash suppressor. The lower features an integrated oversized trigger guard and flared magwell for faster STANAG magazine reloads, and the rifle uses an Angstadt Arms 10-inch free-float M-LOK handguard, B5 Systems pistol grip, and (on braced models) an SB Tactical SBA3 with five-position adjustable length of pull. The fire control is an Angstadt Arms EMT trigger. Available in black anodize, Magpul FDE and Tactical Grey Cerakote, the platform was later marketed under the SLK-15 name for the full-length rifle.
Specifications
| Weight (empty) | 2268 g (80.0 oz) |
| Weight (loaded) | 2630 g (92.8 oz) |
| Overall Length | 686 mm (27.01") |
| Barrel Length | 292 mm (11.50") |
| Height | 200 mm (7.87") |
| Width | 64 mm (2.52") |
| Action Type | Gas Operated Direct Impingement |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Stage |
| Trigger Pull | 24 N (5.4 lbf) |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 850 m/s (2789 fps) |
| Muzzle Energy | 1445 J (1066 ft·lbf) |
| Effective Range | 300 m (328 yd) |
| Maximum Range | 2700 m (2953 yd) |
| Barrel Rifling | Right Hand |
| Rifling Twist | 178 mm (7.01") |
| Number of Grooves | 6 |
| Frame Material | Aluminum Alloy |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Anodized |
Calibers
- 5.56x45mm NATO · primary · 5.56mm NATO — also known as 5.56 NATO, 5.56x45mm, .223 Remington (parent)
Features
- Firing modes: Semi Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety Selector, Firing Pin Safety
- Features: Ar15 Pattern, Stanag Magazine, M Lok Handguard, Free Floating Handguard, Threaded Barrel, Flared Mag Well, Picatinny Rail, Billet Receivers, Ambidextrous Controls
Variants
- Angstadt Arms UDP-556 10.5" Pistol — Barrel Length
- Angstadt Arms UDP-556 16" Rifle — Rifle
- Angstadt Arms UDP-556 SBR — Short Barrel Rifle
- Angstadt Arms UDP-556 FDE — Finish
- Angstadt Arms UDP-556 Tactical Grey — Finish
Production
Production years: 2016-present
Origin
Country of origin: United States
Designer: Angstadt Arms
Notes
Sold in 10.5 in and 11.5 in pistol/SBR forms and a 16 in rifle. The 16-inch rifle was rebranded as the SLK-15. Approximately 5 lbs in the 11.5-inch pistol configuration; overall length around 27 inches. Uses standard AR-15 STANAG magazines.
Background
Angstadt Arms expanded beyond pistol-caliber AR-9s with the UDP-556, applying its billet receiver and ultra-light handguard design language to a 5.56 carbine line later badged SLK-15.