The Spartan Armor AR550 is a Special Threat Rated Level III+/RF2 hard armor plate manufactured in the USA from American AR550 ballistic-grade steel. Independently tested at an NIJ-accredited laboratory against NIJ 0101.06 threat parameters, the AR550 stops 5.56 M193, 5.56 M855/SS109, 7.62 M80 ball, and 7.62×51 .308 Winchester at velocities up to 3,100 fps. Available in 10x12, 11x14, and Medium ESAPI sizes, in Shooters Cut or High Mobility Cut, with single-curve or Advanced Triple Curve (ATC) geometry, and a choice of Base Coat or Encapsaloc Full Coat.

Who this is for

• Law enforcement officers needing reliable Level III+ rifle-rated coverage at a cost-effective per-plate price.
• Military personnel and security professionals requiring multi-hit hard armor protection with proven AR550 metallurgy.
• Responsible civilians building home defense, range training, or vehicle-staged emergency preparedness setups.

Ballistic performance

AR550 is a through-hardened abrasion-resistant steel rated to Brinell hardness 550 — approximately 15% harder than the AR500 baseline. The added hardness allows the plate to defeat higher-velocity 5.56 rounds that defeat softer steel, including 5.56 M193 at 3,100 fps multi-hit and 7.62×51 M80 ball at 2,780 fps multi-hit. AR550 plates ship lab-certified and are manufactured entirely in the USA from American steel.

The Full Coat option provides superior fragmentation and spall mitigation, enhancing user safety by capturing bullet fragments and copper jacket spall that would otherwise deflect outward at high velocity. Base Coat provides corrosion protection only.

Independent ballistic test data

Threat data below is from Spartan Armor Systems' independent NIJ-accredited lab test report.

Specifications

Fit and carrier compatibility

The 10x12 Shooters Cut is the standard SAPI/ESAPI plate-pocket size and fits the majority of plate carriers from Spartan, Crye, Ferro, Velocity Systems, and Shellback Tactical. The 11x14 size provides extended coverage for users with larger torso dimensions; the 9.5x12.5 Medium ESAPI is sized for issued military and law enforcement carriers. High Mobility Cut shaves additional weight for prolonged dynamic movement. Refer to the size guide for carrier-specific fit before ordering.

Frequently asked questions

Is the AR550 NIJ Certified or NIJ Listed?

The single-curve Full Coat variants are listed by NIJ as compliant with the 0101.06 standard at Level III. Other AR550 variants in this product family are marketed as Special Threat Rated Level III+/RF2, meaning they are independently tested at NIJ-accredited laboratories against NIJ 0101.06 threat parameters but are not all submitted to NIJ's Compliance Testing Program for inclusion on the Compliant Products List. Verify the specific variant against the NIJ CPL before duty-contract use.

Will the AR550 stop M855A1 or armor-piercing rounds?

No. The AR550 is rated against M193, M855/SS109, M80 ball, and 7.62×51 .308 Winchester at velocities up to 3,100 fps. M855A1 EPR uses a hardened steel penetrator that defeats Level III+ steel armor; choose a Level IV ceramic or composite plate for M855A1, M2 AP, or .30-06 AP threats.

What does the Encapsaloc Full Coat actually do?

When a high-velocity round strikes uncoated steel, the bullet fragments and copper jacket material can deflect laterally at near-original velocity. The Full Coat option provides superior fragmentation and spall mitigation, enhancing user safety by capturing these fragments before they escape the plate face. Base Coat provides corrosion protection only and does not address spall.

How heavy is a full two-plate setup?

Two 10x12 Base Coat plates weigh 16 lbs 2 oz (8 lbs 1 oz each). Two 10x12 Full Coat plates weigh 17 lbs 4 oz. The High Mobility Cut shaves roughly 1 lb 7 oz per plate. Add the carrier weight (typically 2-4 lbs) for total loadout. For prolonged daily wear, a lighter UHMWPE or hybrid composite plate may be more sustainable.

What is the difference between Single Curve and Advanced Triple Curve (ATC)?

Single Curve plates sit flatter against the chest and are comfortable for stationary or short-duration use. Advanced Triple Curve geometry contours more aggressively around the torso, improving ergonomics for prolonged dynamic movement at a marginal weight increase. ATC fits a slightly more restricted set of plate carriers — check the size guide.

Can the AR550 be shipped to my state?

The AR550 cannot be shipped to New York or Connecticut due to state body armor restrictions, and is subject to US export regulations. Under 18 U.S.C. § 931, anyone with a federal felony conviction for a crime of violence is prohibited from purchasing or possessing body armor. By placing an order you confirm you are legally eligible to own body armor in your jurisdiction.