If you want a 10mm load that uses the full potential of the cartridge, Underwood is one of the first names shooters bring up. Underwood 10mm ammo lists some of the highest speeds in our 10mm catalog. It also comes in a wide spread of bullet types, from hard cast lead to solid copper. That range is great, but it can make choosing hard. This guide breaks the Underwood lineup into groups and matches each one to a job.
Why Shooters Pick Underwood 10mm
The 10mm Auto came out in the early 1980s. It was built as a powerful semi-auto pistol round. Over time, many factory loads were toned down. Underwood’s loads lean the other way.
Here is a quick comparison from our own catalog. The Federal American Eagle 180-grain FMJ lists 1,030 fps. The Underwood 180-grain FMJ flat nose lists 1,300 fps with the same bullet weight. That gap is why people ask, “Is Underwood ammo good?” For shooters who want more speed and energy, the answer is often yes. For new shooters, the extra recoil can be a lot.
Always make sure your pistol is in good shape and is made for the 10mm Auto. Stout loads add wear and recoil.
Underwood 10mm Ammo by Bullet Type
Hard Cast Flat Nose
These are solid lead bullets with a wide, flat nose and a Black Cherry polymer coating. They do not expand. Hunters and hikers pick them when deep, straight penetration matters most. The Underwood 220-grain hard cast lists 1,200 fps and 704 ft-lb. The 200-grain version lists 1,250 fps and 694 ft-lb.
Lehigh Solid Copper: Xtreme Penetrator
The Xtreme Penetrator is a fluted, solid copper bullet with no hollow point. The flutes are designed to disrupt tissue without the bullet opening up. It is lead free. The Underwood Xtreme Penetrator 140-grain lists 1,500 fps and 700 ft-lb.
Lehigh Solid Copper: Xtreme Defender and Xtreme Hunter
These use a different fluted design aimed at defense and hunting. The Underwood Xtreme Defender 115-grain lists 1,700 fps and 738 ft-lb. The 150-grain Xtreme Hunter lists 1,425 fps. We also stock Platinum Edition versions of these Lehigh loads.
Jacketed Hollow Points
Underwood loads Hornady XTP and Nosler hollow point bullets. The XTP is known for controlled expansion. The Underwood 155-grain XTP lists 1,500 fps and 774 ft-lb. The Underwood 135-grain Nosler JHP lists 1,600 fps and 767 ft-lb.
Barnes TAC-XP
The TAC-XP is an all-copper hollow point. It is lead free and holds its weight well. The 155-grain Underwood TAC-XP lists 1,400 fps.
FMJ Range Loads
Underwood sells FMJ flat nose loads in 50-round boxes for practice. The Range Supply 180-grain FMJ lists 1,250 fps. Train with ammo close to your carry load so the recoil feels the same.
Underwood 10mm Comparison Table
| Load | Grain | Bullet | Velocity (fps) | Energy (ft-lb) |
|---|---|---|---|---|
| Xtreme Defender 115 | 115 | Fluted copper | 1,700 | 738 |
| Nosler JHP 135 | 135 | JHP | 1,600 | 767 |
| Xtreme Penetrator 140 | 140 | Fluted copper | 1,500 | 700 |
| Xtreme Hunter 150 | 150 | Fluted copper | 1,425 | 677 |
| Nosler JHP 150 | 150 | JHP | 1,500 | 750 |
| XTP 155 | 155 | JHP | 1,500 | 774 |
| TAC-XP 155 | 155 | Copper HP | 1,400 | 675 |
| FMJ 165 | 165 | FMJ | 1,400 | 718 |
| XTP 180 | 180 | JHP | 1,300 | 676 |
| FMJ FN 180 | 180 | FMJ | 1,300 | 676 |
| XTP 200 | 200 | JHP | 1,250 | 694 |
| Hard Cast 200 | 200 | Hard cast FN | 1,250 | 694 |
| Hard Cast 220 | 220 | Hard cast FN | 1,200 | 704 |
All speeds and energies are Underwood’s published figures. Your pistol’s barrel length will change them.
Is 10mm Good for Bear Defense?
This is the top question we hear about the 10mm. Many guides and hikers in bear country carry one. If you go that route, most choose a non-expanding bullet built for depth, like a hard cast flat nose or the Xtreme Penetrator. Heavy bullets in the 200 to 220-grain range are common picks.
Keep a few things in mind. Shot placement matters more than any load. Bears are fast and tough, and a handgun is a last line. Many agencies also suggest bear spray. Practice drawing and shooting under stress. Check local rules on carrying firearms in parks and wild areas.
How to Choose Underwood 10mm Ammo
- Bear country and hogs: hard cast 200 or 220-grain, or the Xtreme Penetrator.
- Deer hunting where legal: XTP hollow points or the Xtreme Hunter. Check your state’s handgun hunting rules.
- Home and personal defense: XTP, Nosler JHP or Xtreme Defender. Laws on hollow points vary, so check local rules.
- Practice: FMJ flat nose in 50-round boxes.
To see how other makers compare, read our Buffalo Bore 10mm ammo guide or learn how to read 10mm gel test results.
Shop Underwood 10mm Ammo
Find the full lineup in our Underwood 10mm ammo category, or compare every brand in our 10mm ammo section. Start with one box of your carry load and one of practice ammo, and make sure both run in your gun.
Frequently Asked Questions
Is Underwood ammo good?
Underwood has a strong name among 10mm shooters. Its loads list higher speeds than many standard 10mm rounds in our catalog. It also offers premium bullets like Hornady XTP, Nosler JHP, Barnes TAC-XP and Lehigh solid copper. Expect more recoil than milder loads, and test any load in your own pistol.
Can a 10mm kill a bear?
A 10mm can stop a bear with good shot placement and the right bullet, and many people carry one in bear country. Most choose heavy, non-expanding bullets such as hard cast flat nose loads. A handgun is still a last resort, and bear spray is a common first choice.
What Underwood 10mm load is best for bear defense?
Most people pick a non-expanding bullet built for depth. Underwood’s 200 and 220-grain hard cast flat nose loads and the 140-grain Xtreme Penetrator are the usual choices. Make sure the load runs in your pistol and that you can control the recoil.
Who makes full power 10mm ammo?
Several makers offer hot 10mm loads. In our catalog, Underwood and Buffalo Bore list some of the highest speeds. For example, the Underwood 180-grain FMJ lists 1,300 fps, while the Federal American Eagle 180-grain lists 1,030 fps.
Is Underwood 10mm safe in my pistol?
Underwood loads are made for firearms chambered in 10mm Auto that are in good working order. Stout loads add recoil and wear. If you are unsure, ask the maker of your pistol or a qualified gunsmith before shooting them.
