Last reviewed: 2026-04-18 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.
When you’re loading 45 Colt Xtreme Defender ammo into a lever gun or single-action revolver intended for woods carry or home defense, you’re staking terminal performance on a bullet that refuses to compromise. Underwood machines each 135-grain Lehigh Xtreme Defense projectile from solid copper, cuts radial flutes into the nose, and loads it to 1410 feet per second — producing a permanent wound cavity that dwarfs traditional expanding bullets while punching through intermediate barriers that would plug or deform a hollowpoint. The 45 Colt (Long Colt) cartridge, dating to 1872, sees renewed relevance when paired with barrier-blind projectiles engineered to FBI penetration standards.
Built for the Box
Underwood employs CNC machining to cut flutes into the nose of each solid-copper projectile. Those channels force hydraulic energy radially inward during tissue contact, building pressure that tears a wound track measuring over 100 percent wider than conventional expanding bullets — all while the projectile itself sheds no mass and maintains a straight wound channel. Nickel-plated brass cases resist corrosion during magazine or cylinder storage, feed cleanly in lever actions, and accept Boxer primers for straightforward reloading. Flash-suppressed powder keeps your sight picture intact during low-light encounters. Each component is manufactured in the United States and tested through production firearms before release.
Performance at a Glance
| Spec | Value |
|---|---|
| Caliber | 45 Colt (Long Colt) |
| Bullet weight | 135 grains |
| Bullet type | Lehigh Xtreme Defense — fluted solid copper |
| Muzzle velocity | 1410 fps |
| Muzzle energy | 596 ft-lbs |
| Rounds per box | 20 |
| Case | Nickel-plated brass |
| Primer | Boxer |
| Corrosive | No |
| Reloadable | Yes |
| Intended use | Self-defense |
| Manufacturer | Underwood Ammo (USA) |
At 135 grains, this load sits at the lighter end of the 45 Colt spectrum — but velocity compensates. The fluted nose ensures you retain penetration depth even when the shot passes through an interior wall or a car door before reaching the target. Browse the full 45 long colt ammo catalog to compare hunting, plinking, and defensive options across grain weights and bullet profiles.
Safe Handling & Compliance
Federal law requires purchasers to be at least 18 years old for rifle and shotgun ammunition, and at least 21 for handgun ammunition. Ammunition cannot be shipped to certain states, counties, and cities — review our ammunition shipping restrictions before ordering. Store ammunition in a cool, dry location away from heat sources and out of reach of unauthorized users.
- Follow the four universal rules: treat every firearm as loaded, never point at anything you’re unwilling to destroy, keep your finger off the trigger until sights are on target, and identify your target and what lies beyond it.
- Verify current state and local laws governing ammunition purchase, possession, and use — particularly if you reside in California, Connecticut, Illinois, Massachusetts, New Jersey, New York, or Washington D.C.
- This ammunition contains lead components; wash hands after handling. California Prop 65 warning applies — see www.P65Warnings.ca.gov.
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