The Underwood 9mm Luger +P+ 90gr Xtreme Defender Platinum load (Underwood part no. 877) is a self-defense cartridge built around a 90-grain solid copper monolithic bullet. It is based on Underwood’s Xtreme Penetrator line, with a fluted nose tuned for weight and velocity to reach penetration of up to 18 inches while opening a large permanent wound cavity. The platinum finish protects the copper from oxidation and darkening in long storage, and the nickel-plated brass case adds corrosion resistance. It comes in a 20-round box for pistols rated for +P+ ammunition.

Key Specifications

• The cartridge is 9mm Luger +P+, a high-pressure loading that belongs only in firearms rated for that pressure.
• The bullet weighs 90 grains, a light projectile that lets the load reach high velocity.
• The bullet is a solid monolithic copper design with a platinum finish, which resists oxidation and cuts barrel wear compared with a standard monolithic projectile.
• Muzzle velocity is 1550 fps, a supersonic speed for a 90-grain bullet.
• Muzzle energy is 480 ft-lbs, the figure Underwood lists for this load.
• The bullet diameter is 0.355 inch, the standard bore size for 9mm Luger.
• The case is nickel-plated brass, which feeds smoothly, resists corrosion and cleans up easily for reloaders.
• The bullet is lead free, a copper-only build with no lead core.
• Underwood lists this load as suppressor safe, which matters for owners who shoot a suppressed pistol.
• Each box holds 20 rounds, a standard defensive count that covers a spare magazine or two.

Frequently Asked Questions

What does +P+ mean for this Underwood load? This listing is the 9mm Luger +P+ version of the 90-grain Xtreme Defender Platinum, which Underwood lists separately from its +P and standard 9mm Luger versions. Confirm that your pistol is rated for +P+ ammunition before you buy.

Can I shoot it in a Sig P365 with an aftermarket barrel? Underwood says aftermarket Sig P365 conversion barrels are not recommended for use with its +P and +P+ 9mm ammunition, and that all of its testing and validation is performed with factory Sig P365 barrels.

Does this load contain lead? No. Underwood lists the bullet as copper and lead free, and it lists the load as safe to use in a suppressor.

Buy the Underwood Xtreme Defender Platinum 9mm Luger +P+ 90gr Solid Monolithic, 20-Round Box

Order the Underwood +P+ load from our Lubbock, Texas gun shop and it ships fast to your door. Browse more handgun ammunition when you are comparing defensive loads.