Rifle · SAAMI (not in current Z299)
7mm STW
The original ultra-fast 7mm magnum — a long-case belted design pushing 140-grain bullets past 3,300 fps.
- Caliber
- 0.284″ · 7.214 mm
- Introduced
- 1979
- Case
- Belted
- Parent
- 8mm Remington Magnum
- Primary use
- Hunting, Target
- Status
- Active
- Introduced
- 1979
- Type
- Rifle
- Origin
- United States
- Inventor
- Layne Simpson
- Manufacturer
- Remington / Nosler / Hornady
- Standard
- SAAMI (not in current Z299)
- Status
- Active
- Availability
- Limited
- Case capacity
- 97 gr H₂O
- Twist (typical)
- 1:9
- Primer
- Large Rifle Magnum
- Case type
- Belted
- Max pressure
- 63,817 psi, CIP transducer
- Eff. range
- 800 yd
- Max range
- 5900 yd
- Recoil
- 30–42 ft·lb
Ballistics
Published velocity/energy data isn't available for 7mm STW. Parent case: 8mm Remington Magnum.
Performance
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
SAAMI · verified| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 7.21 | 0.284 | ✓ |
| Neck ⌀ | 8.00 | 0.315 | ✓ |
| Shoulder ⌀ | 12.37 | 0.487 | ✓ |
| Shoulder angle | 25° | — | ✓ |
| Base ⌀ | 13.02 | 0.513 | ✓ |
| Rim ⌀ | 13.51 | 0.532 | ✓ |
| Belt ⌀ | 13.50 | 0.531 | ~ |
| Rim thickness | 1.27 | 0.050 | ✓ |
| Neck length | 7.06 | 0.278 | ≈ |
| Case length | 72.39 | 2.850 | ✓ |
| Overall length | 91.44 | 3.600 | ✓ |
Size vs familiar rounds
Drawn at true 1:1 — every case is accurate relative to the others. Absolute size depends on your screen's pixel density, so measuring one against a real ruler may be off. 7mm STW is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Suitable powders
4 reloading powders listed for 7mm STW, fastest to slowest. Cross-reference in the finder →
Reloading costestimate cost per round vs factory
Estimate your cost per round and how it compares to factory. Inputs are yours — nothing is stored.
Cost estimate only — not load data. Charge weight is your input; follow published manuals for safe charges.
Firearms chambered in 7mm STW
Lineage
Connected reference
History
Developed in 1979 by Layne Simpson, firearms editor at Shooting Times magazine, by necking down the 8mm Remington Magnum case to 7mm. Simpson nicknamed it the Shooting Times Westerner. It remained a wildcat for nearly two decades before Remington standardized it and began producing ammunition in 1996. At its introduction, it was the fastest production 7mm cartridge available, offering velocities that experienced hunters found genuinely useful at extreme range. Barrel life was the price — the large powder charge erodes throats quickly.
FAQs
- What twist rate does 7mm STW use?
- 7mm STW typically uses a 1:9 twist rate.
- What bullet diameter is 7mm STW?
- 7mm STW uses a 0.284″ (7.214 mm) diameter bullet.
- Is 7mm STW still in production?
- 7mm STW is active; typical availability is limited.
- What is 7mm STW used for?
- 7mm STW is primarily used for hunting, target.
- What is 7mm STW based on?
- 7mm STW is derived from the 8mm Remington Magnum case.
- What are the best powders for 7mm STW?
- Reloading powders commonly listed for 7mm STW include MRP2, N570, Reloader 25, Reloader 26.
Sources & provenance
- Standard SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) — ANSI/SAAMI Z299.4 – 2015 (Centerfire Rifle) — Velocity & Pressure / Cartridge & Chamber Drawings · grain_ballistics, representative_gun archived
- Standard SAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawings archived
- Manufacturer Remington — Remington Ballistics — 7mm STW (archived remington.com, snapshot 1999-10-04) · representative_gun, grain_ballistics
- Manufacturer Nosler — Nosler Trophy Grade 7mm STW 160gr AccuBond Ammunition (#60047) · representative_gun, grain_ballistics archived
- Manufacturer Choice Ammunition — 7mm STW 175 Grain Hornady ELD-X Hunting, 100% Hand Loaded · representative_gun, grain_ballistics archived
- Manufacturer Federal Premium — Federal Premium Trophy Bonded Tip 7mm STW P7STWTT1 (archived federalpremium.com, snapshot 2023-03-22) · grain_ballistics, representative_gun
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 20 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
