Underwood Xtreme Penetrator ammunition in .357 Magnum (brand part no. 836) is built for shooters who carry this round for personal or home defense. Underwood builds this load from consistent, quality-checked components for dependable performance shot after shot. At the heart of this load is the 140 gr bullet with an Xtreme Penetrator design, matched to the .357 Magnum platform shooters already run. In our handgun ammunition lineup, this is the Underwood load built for that job.

Key Specifications

• The caliber is .357 Magnum, one of the most carried, most available cartridges for the platform.
• The bullet weighs 140 gr, sized for the terminal performance this load is built around.
• The projectile is an Xtreme Penetrator design, engineered to expand and transfer energy on impact.
• The case is Nickel-Plated Brass, reloadable for handloaders who want to reuse brass.
• Each box holds 20 rounds, enough to confirm zero and still have rounds left to shoot.
• Cases ship 10 boxes to a case, a convenient bulk quantity for high-volume shooters.
• Cost works out to about $2.13 per round, keeping practice sessions affordable.
• The box ships at approximately 0.70 lbs, handy for planning shipping costs on a bulk order.
• This is a centerfire cartridge, ignited by a replaceable primer rather than a rimfire priming ring.
• The Xtreme Penetrator bullet uses a fluted nose design to cut a wound channel through deep penetration rather than relying on expansion.
• The fluted design is engineered to defeat heavy clothing barriers that can clog and defeat a standard hollow point.

Frequently Asked Questions

Is this a good defensive round in .357 Magnum? Yes, the expanding bullet design is built for controlled expansion and reliable stopping power, a common choice for defensive .357 Magnum carry.

How many rounds come in a box? Each box holds 20 rounds of .357 Magnum.

Can I order this by the case? Yes, this load ships 10 boxes to a case for shooters who want to order in bulk.

Buy the Underwood Xtreme Penetrator .357 Magnum 140 gr, 20-Round Box

Stock up before the next range trip or hunt, and let the ammunition be the one thing you don’t have to think about. Order from our Lubbock, Texas gun shop and it ships fast to your door.