Underwood .40 S&W Ammo
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Underwood Ammo 10mm Auto 140 Grain Xtreme Penetrator Solid Monolithic Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 648
Brand:
Underwood Ammo
Bullet Type:
Xtreme Penetrator
Caliber:
.40 S&W
Capacity:
20
Finish Per Color:
Nickel Plated Brass
Grains:
140 grain
From:
$37.00
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12
(3)
Underwood Ammo 10mm Auto 135 Grain Jacketed Hollow Point Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 231
Brand:
Underwood Ammo
Bullet Type:
Jacketed Hollow Point (JHP)
Caliber:
.40 S&W
Capacity:
20
Finish Per Color:
Nickel Plated Brass
Rounds:
20
From:
$22.32
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10
(3)
Underwood Ammo 10mm Auto 180 Grain XTP Jacketed Hollow Point Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 243
Brand:
Underwood Ammo
Bullet Type:
Hollow Point
Caliber:
.40 S&W
Rounds:
20
(0)
Underwood Ammo 10mm Auto 150 Grain Xtreme Hunter Solid Monolithic Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 900
Brand:
Underwood Ammo
Bullet Type:
Solid
Caliber:
.40 S&W
Capacity:
20
Finish Per Color:
Nickel Plated Brass
Rounds:
20
(3)
Underwood Ammo 10mm Auto 155 Grain Jacketed Hollow Point Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 232
Brand:
Underwood Ammo
Bullet Type:
Jacketed Hollow Point (JHP)
Caliber:
.40 S&W
Capacity:
20
Finish Per Color:
Nickel Plated Brass
Rounds:
20
(0)
Underwood Ammo Xtreme Penetrator, .40 S&W, 140 Grain, Solid Monolithic, Nickel Plated Brass Case, Centerfire Pistol Ammo, 20 Rounds Box, 829
Brand:
Underwood Ammo
Bullet Type:
Hollow Point
Caliber:
.40 S&W
Grains:
140 grain
Rounds:
20
(0)
Underwood Ammo 10mm Auto 150 Grain Xtreme Hunter Solid Monolithic Nickel Plated Brass Cased Pistol Ammo, Platinum Edition, 20 Rounds, 942
Brand:
Underwood Ammo
Bullet Type:
Solid
Caliber:
.40 S&W
Capacity:
20
Finish Per Color:
Nickel Plated Brass
Rounds:
20
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Underwood Ammo 10mm Auto 115 Grain Xtreme Defender Solid Monolithic Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 810
Brand:
Underwood Ammo
Bullet Type:
Hollow Point
Caliber:
.40 S&W
Rounds:
20
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Underwood Ammo .40 S&W 200 Grain Coated Hard Cast Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 740
Brand:
Underwood Ammo
Bullet Type:
Flat Nose (FN)
Caliber:
.40 S&W
Capacity:
20
Finish Per Color:
Nickel Plated Brass
Rounds:
20
(0)
Underwood Ammo .40 S&W 155 Grain Jacketed Hollow Point Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 223
Brand:
Underwood Ammo
Bullet Type:
Jacketed Hollow Point (JHP)
Caliber:
.40 S&W
Capacity:
20
Finish Per Color:
Nickel Plated Brass
Rounds:
20
(0)
Underwood Ammo .40 S&W 115 Grain Xtreme Defender Solid Monolithic Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 811
Brand:
Underwood Ammo
Bullet Type:
Hollow Point
Caliber:
.40 S&W
Grains:
115 grain
Rounds:
20
(0)
Underwood Ammo 10mm Auto 150 Grain Jacketed Hollow Point Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 235
Brand:
Underwood Ammo
Caliber:
.40 S&W
Rounds:
20
(0)
Underwood Ammo .40 S&W 200 Grain Jacketed Hollow Point Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 228
Brand:
Underwood Ammo
Bullet Type:
Jacketed Hollow Point (JHP)
Caliber:
.40 S&W
Capacity:
20
Finish Per Color:
Nickel Plated Brass
Rounds:
20
(0)
Underwood Ammo .40 S&W 140 Grain Maximum Expansion Solid Monolithic Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 250
Brand:
Underwood Ammo
Bullet Type:
Hollow Point
Caliber:
.40 S&W
Grains:
140 grain
Rounds:
20
(0)
Underwood Ammo Extreme Defender, .40 S&W, 100 Grain, Solid Monolithic, Nickel Plated Brass Cased, Centerfire Pistol Ammo, 20 Rounds, 862
Brand:
Underwood Ammo
Bullet Type:
Soft Point
Caliber:
.40 S&W
Rounds:
20
(0)
Underwood Ammo 40 S&W 165Gr Bonded Jhp 20Rd 10Bx/Cs 224
Brand:
Underwood Ammo
Caliber:
.40 S&W
Rounds:
20
(0)
Underwood Ammo 10mm Auto 100 Grain Solid Monolithic Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 861
Brand:
Underwood Ammo
Bullet Type:
Soft Point
Caliber:
.40 S&W
Grains:
100 grain
Rounds:
20
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40 S&W - 150 Grain JHP - Underwood - 20 Rounds
Brand:
Underwood Ammo
Bullet Type:
Jacketed Hollow Point (JHP)
Caliber:
.40 S&W
Capacity:
20
Finish Per Color:
Nickel Plated Brass
Rounds:
20
(0)
40 S&W - 115 Grain Xtreme Defender - Underwood - 20 Rounds
Brand:
Underwood Ammo
Caliber:
.40 S&W
Rounds:
20
(3)
Underwood Ammo 10mm Auto 180 Grain Bonded Jacketed Hollow Point Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 244
Brand:
Underwood Ammo
Bullet Type:
Hollow Point
Caliber:
.40 S&W
Rounds:
20
(0)
40 S&W - 180 Grain JHP - Underwood - 20 Rounds
Brand:
Underwood Ammo
Caliber:
.40 S&W
Rounds:
20
(3)
Underwood Ammo 10mm Auto 165 Grain Jacketed Hollow Point Nickel Plated Brass Cased Pistol Ammo, 20 Rounds, 237
Brand:
Underwood Ammo
Caliber:
.40 S&W
Rounds:
20
Marketplace Insights
★ 5.0/5
based on 16 customer reviews across 24 variants from 17 retailers
Outstanding 10mm ammunition highly praised for true full-power loads, reliability, and superior performance in hunting and large animal defense applications.
What customers like
Full Power Performance44%
This aint no watered down retail factory ammo. This is true full power 10mm.
Large Animal Defense44%
I carry it for large animal defense hiking in the mountains.
Reliable & Consistent38%
hunting & self defense. Always reliable Count on That!
Hunting Effectiveness31%
I've took deer and hogs. The perfect example of good.
Common concerns
Strong Recoil31%
Puts a stinging on your hand if not looking for it lol
Frequently Asked Questions
Underwood .40 S&W Ammo
What is the hardest hitting 40 cal ammo?
"Hardest hitting" depends on your goal. For self-defense, Winchester Ranger Talon 180-grain and Black Hills 155-grain JHP lead in terminal performance. For maximum velocity and energy, Underwood's 100-grain Xtreme Defender loads exceed 1,500 fps with over 500 ft-lbs of energy, trading deeper penetration for higher impact energy.
Is underwood ammunition any good?
Underwood ammunition is well-regarded for consistent performance, particularly in self-defense loads. Their rounds deliver reliable expansion and high velocity. Prices range from roughly $20–$54 per box. Quality control is generally strong, and the brand has a solid reputation among handgun and rifle shooters.
How long can 40 cal ammo be stored?
Properly stored .40 S&W ammunition remains functional for decades. Keep rounds in a cool, dry place away from moisture and temperature fluctuations. Manufacturers typically recommend use within ten years, but well-preserved ammunition often lasts 50 years or more. Poor storage conditions can degrade ammo within just a few years.
Is 40 S&W worth it?
The .40 S&W delivers more energy than 9mm with manageable recoil, making it effective for self-defense. However, 9mm ammunition is cheaper, more available, and modern defensive loads have narrowed the performance gap. If your pistol is already chambered in .40, it remains a capable choice.
What is 40 S&W ammo?
.40 S&W is a handgun cartridge introduced in 1990 by Smith & Wesson and Winchester. Derived from the 10mm Auto, it balances stopping power with manageable recoil. Popular for self-defense, law enforcement, and target shooting, it is loaded by major manufacturers including Winchester, Remington, and Black Hills.