Last reviewed: 2026-04-18 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.
The Fort Scott Munitions TUI 243 Winchester 58-grain solid copper round is a lead-free hunting cartridge designed around a patented Tumble Upon Impact projectile. Unlike traditional expanding bullets, the TUI design relies on end-over-end tumbling through water-based tissue to create wound channels. Machined from solid copper on CNC lathes, the 58-grain monolithic bullet launches at 3870 fps from a 24-inch barrel, delivering 1929 ft-lbs of muzzle energy. The lead-free construction meets non-toxic ammunition requirements in restricted hunting zones. Brass cases and Boxer primers allow for reloading.
Built for the Box
Fort Scott Munitions machines each TUI projectile from solid copper rod stock using computer-controlled lathes. The manufacturing process holds tight tolerances across production runs — no jacket separations, no core shift, no inconsistency between rounds. The 58-grain weight sits at the lighter end of the 243 Winchester spectrum, prioritizing velocity over mass. With a G1 ballistic coefficient of 0.454, the bullet sheds velocity faster than heavier boat-tail designs, but the supersonic flight envelope extends well beyond typical deer and hog engagement ranges.
The Numbers
| Spec | Value |
|---|---|
| Caliber | 243 Winchester |
| Bullet weight | 58 grains |
| Bullet type | Solid copper (TUI design) |
| Muzzle velocity | 3870 fps (24″ test barrel) |
| Muzzle energy | 1929 ft-lbs |
| G1 BC | 0.454 |
| Lead free | Yes |
| Case | Brass |
| Primer | Boxer |
| Corrosive | No |
| Reloadable | Yes |
| Rounds/box | 20 |
| Intended use | Hunting |
| Manufacturer | Fort Scott Munitions (USA) |
The TUI projectile tumbles through hydrostatic tissue rather than expanding. Penetration depth and permanent wound cavity characteristics differ from conventional expanding bullets — the design favors deep straight-line penetration with disruption occurring through the length of the wound channel rather than at the entry point. Browse more options in our 243 ammo category.
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.
- Apply the four rules of firearm safety on every range trip and hunt
- Verify current state and local ammunition laws in your jurisdiction before ordering
- This product contains copper — California Proposition 65 warnings apply for trace exposure during handling
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