Product SKU # :TSUW817 |  MPN: 817  | UPC # :816874020149

Underwood Ammunition 

Underwood 9mm Luger +P+ Ammo 90 Grain Xtreme Defender - 817

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Underwood 9mm Luger +P+ Ammo 90 Grain Xtreme Defender - 817
USDTargetSportsUSA24.99
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USDTargetSportsUSA249.90
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You must be 21 years or older to order ammunition. Ammunition must ship UPS ground. Due to safety considerations and legal/regulatory reasons, Ammunition may not be returned. Please check local laws before ordering. By ordering this Ammunition, you certify you are of legal age and satisfy all federal, state and local legal/regulatory requirements to purchase this Ammunition.

Underwood 9mm Luger +P+ Ammo 90 Grain Xtreme Defender - 817

Underwood 9mm Luger +P+ 90 Grain Xtreme Defender ammunition is a high-pressure defensive handgun load designed for personal protection and specialized defensive applications. This 9mm +P ammo uses a solid copper monolithic projectile with a fluted nose profile intended to create consistent terminal performance without depending on traditional hollow point expansion. Loaded to a listed muzzle velocity of 1,550 fps, the 90 grain Xtreme Defender bullet delivers a fast velocity profile. Underwood loads this ammunition in nickel-plated reloadable brass cases with flash-suppressed powder to support defensive use in low-light conditions. The projectile is lead-free and designed as a supersonic handgun load for modern 9mm firearms rated for +P ammunition. Each box contains 20 rounds, while full case quantities include 200 rounds of 9mm Luger +P ammo. Bulk 9mm defensive ammo purchases qualify for free shipping through Target Sports USA.

Features and Specifications:

  • 90 Grain Xtreme Defender Projectile: This 9mm Luger +P ammo uses a solid copper monolithic bullet with a fluted nose design intended for defensive handgun applications.
  • +P Pressure Loading: Loaded above standard 9mm Luger pressure specifications, this ammunition is intended only for firearms rated to safely handle +P ammunition.
  • 9mm Defensive Velocity: Rated at 1,550 fps, this load combines a lightweight-for-caliber projectile with a high-velocity performance profile.
  • Lead-Free Solid Copper Construction: The monolithic copper projectile design eliminates lead content while maintaining bullet integrity during use through intermediate barriers.
  • Nickel-Plated Reloadable Brass Cases: Underwood uses boxer-primed nickel-plated brass cases designed to support reliable feeding, corrosion resistance, and reloadability.
  • Flash-Suppressed Powder Blend: This ammunition is loaded with flash-suppressed powder to help reduce visible muzzle flash during low-light defensive shooting situations.
  • Supersonic Defensive Handgun Ammo: The listed velocity exceeds the speed of sound, placing this load in the supersonic category for defensive 9mm handgun ammunition.

Deep Dive

Overview

This 9mm Luger +P ammo is intended for personal defense applications in compatible handguns rated for higher-pressure ammunition. The solid monolithic projectile design provides an alternative to conventional expanding hollow point handgun ammunition. Its fluted nose geometry is intended to maintain projectile structure while producing consistent defensive performance characteristics. The 90 grain bullet weight combined with a 1,550 fps velocity rating creates a different balance of projectile mass and speed compared to standard-pressure defensive 9mm loads. This ammunition may appeal to shooters seeking a lead-free defensive handgun option with a lightweight, high-velocity bullet profile. Because this is +P ammunition, firearm manufacturer compatibility recommendations should always be reviewed before use. The load is designed as a supersonic defensive handgun round for modern centerfire pistols chambered in 9mm Luger.

History and Development

Underwood Ammo has built its product lineup around high-performance handgun and rifle ammunition designed for defensive, hunting, and specialty shooting applications. The company is known for producing loads that emphasize velocity, energy, and application-specific bullet designs across a wide range of calibers. The Xtreme Defender line was developed as part of the company’s defensive handgun ammunition offerings using solid monolithic projectile technology rather than conventional hollow point expansion methods. This design approach focuses on maintaining bullet integrity while using a fluted nose geometry for defensive performance characteristics. Underwood continues to offer Xtreme Defender ammunition in several popular handgun calibers for concealed carry and personal protection use.

Common Questions and FAQs

  • Is this 9mm ammunition loaded to +P pressure specifications?
    Yes, this load is designated as 9mm Luger +P ammunition and should only be used in firearms rated for +P ammunition.
  • What type of bullet does this ammunition use?
    It uses a 90 grain solid copper Xtreme Defender monolithic projectile with a fluted nose design.
  • Is this ammunition lead-free?
    Yes, the projectile used in this ammunition does not contain lead.
  • What is the listed muzzle velocity for this load?
    Underwood lists the muzzle velocity at 1,550 fps.
  • Are the cases reloadable?
    Yes, this ammunition uses boxer-primed reloadable nickel-plated brass cases.
  • Does this case of 9mm ammo include free shipping?
    Yes, bulk purchases of this 9mm Luger +P ammo qualify for free shipping through Target Sports USA.
  • Can this ammunition be used with aftermarket Sig P365 conversion barrels?
    Underwood does not recommend aftermarket Sig P365 conversion barrels for use with their +P 9mm ammunition. The company states that testing and validation is performed using factory Sig P365 barrels.

The 'Round Up'

Perfect Fit for:

  • Personal Defense

Why It Stands Out:

Underwood 9mm Luger +P 90 Grain Xtreme Defender ammunition is a specialized defensive handgun load built around a solid copper monolithic projectile and high-pressure loading specifications. The fluted Xtreme Defender bullet design offers an alternative to traditional hollow point defensive ammunition while maintaining a lead-free projectile construction. Nickel-plated reloadable brass cases and flash-suppressed powder are included as part of the loading configuration for defensive handgun use. This ammunition is packaged in 20-round boxes with 200-round case quantities available for bulk purchases. Because of its +P pressure rating, this ammunition should only be used in firearms specifically rated for higher-pressure 9mm loads.

Field Details
MPN817
UPC816874020149
ManufacturerUnderwood
PlatformHandgun
Ammo ApplicationPersonal Defense
Ammo TypeSolid Monolithic
Caliber9mm Luger
Grain Weight90
Quantity Per PackageBox of 20 / Case of 200
Test Barrel LengthNot Provided
Muzzle Velocity1550 fps
Muzzle Energy480 ft lbs
Ballistic Coefficient (G1)0.087
Case TypeNickel Plated Brass
Primer TypeCenterfire / Boxer
CorrosiveNo
ReloadableYes
Lead FreeNo
Staked PrimerNot Provided
Country of OriginUSA

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SHIPPING AMMUNITION


Attention Ammunition Buyers You must be 21 years or older to order ammunition. Ammo must ship UPS/FedEx Ground. For safety reasons, we cannot accept returns on ammo. Always, make sure that you use the correct ammunition for your gun. Please check local laws before ordering.


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Target Sports USA only ships ammo to Contiguous 48 states only. We do not ship ammo to Alaska & Hawaii 
   
Proposition 65 Warning
 This product can expose you to chemicals including lead, which are known to the State of California to cause cancer and reproductive harm. For more information go to www.p65warnings.ca.gov.

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Comments and Reviews on Underwood 9mm Luger +P+ Ammo 90 Grain Xtreme Defender - 817
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A++ Quality 9mm rounds from Underwood! Great shipping from TSUSA!
Reviewed by Pete  S
4/30/2026 3:49:52 PM

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About Underwood Ammunition

Underwood Ammunition is proudly made in the USA and is renowned for its high-velocity, hard-hitting performance tailored for self-defense, hunting, and tactical use. Featuring premium product lines like Xtreme Defender, Xtreme Penetrator, and Match Grade, Underwood uses cutting-edge bullet designs from Lehigh Defense and other top suppliers to ensure maximum energy transfer, deep penetration, and precision accuracy. Built with tight quality control and premium components, Underwood rounds are trusted by professionals and serious shooters. Target Sports USA carries Underwood Ammo in bulk with fast shipping and competitive pricing on calibers like 9mm Luger ammo, .380 ACP ammo, .357 Mag ammo, and 38 special ammo.

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