Lindcott Armory Rifle · SAAMI
.257 Roberts
Classic quarter-bore beloved by riflemen.
- Caliber
- 0.257″ · 6.528 mm
- Introduced
- 1934
- Case
- Rimless
- Parent
- 7mm Mauser
- Primary use
- Hunting, Target
- Status
- Active
- Introduced
- 1934
- Type
- Rifle
- Origin
- United States
- Inventor
- Ned Roberts / A.O. Niedner
- Manufacturer
- Remington (commercial)
- Standard
- SAAMI
- Status
- Active
- Availability
- Moderate
- Case capacity
- 55 gr H₂O
- Twist (typical)
- 1:10
- Primer
- Large Rifle
- Case type
- Rimless
- Max pressure
- 54,000 psi
- Eff. range
- 300 yd
- Max range
- 4000 yd
- Recoil
- 8–12 ft·lb
Ballistics
Real trajectory computed from a representative load — Hornady Superformance SST 117 gr, 2,946 fps, BC 0.222 G7 · 100 yd zero.
| Range | Velocity | Energy | Drop (in) | Drop (MOA) |
|---|---|---|---|---|
| 0 yd | 2945 | 2253 | -1.5″ | — |
| 100 yd | 2737 | 1945 | +0.1″ | 0.0 |
| 200 yd | 2535 | 1670 | -3.1″ | -1.5 |
| 300 yd | 2342 | 1425 | -11.6″ | -3.7 |
| 400 yd | 2157 | 1209 | -26.5″ | -6.3 |
| 500 yd | 1980 | 1018 | -48.8″ | -9.3 |
| 600 yd | 1810 | 851 | -80.1″ | -12.7 |
| 700 yd | 1646 | 703 | -122.1″ | -16.7 |
| 800 yd | 1489 | 576 | -176.8″ | -21.1 |
Point-mass G7/G1 drag model, standard atmosphere — within ~2% of reference solvers to 1000 yd; real barrels and conditions vary. Open in Ballistic Compare →
Performance
Buy links open .257 Roberts ammunition at Rivertown Munitions.
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 ⌀ | 6.53 | 0.257 | ✓ |
| Neck ⌀ | 7.37 | 0.290 | ✓ |
| Shoulder ⌀ | 10.95 | 0.431 | ✓ |
| Shoulder angle | 20.8° | — | ✓ |
| Base ⌀ | 11.97 | 0.471 | ✓ |
| Rim ⌀ | 12.01 | 0.473 | ✓ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.24 | 0.049 | ✓ |
| Neck length | 8.16 | 0.321 | ≈ |
| Case length | 56.72 | 2.233 | ✓ |
| Overall length | 70.61 | 2.780 | ✓ |
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. .257 Roberts is highlighted below.
Factory loads
In production — 32 active loads across 15 brands. Top 15 shown · see all 36 →.
| Brand | Load | Grain | Bullet | FPS | ft·lb | BC |
|---|---|---|---|---|---|---|
| Hornady | Superformance SST | 117 | SST | 2,946 | 2,254 | 0.222 G7 |
| Hornady | Custom | 117 | SST | 2,940 | 2,245 | 0.222 G7 |
| Nosler | Trophy Grade Partition | 120 | Partition | 2,800 | 2,089 | 0.391 G1 |
| Barnes | TTSX | 100 | TTSX BT | 3,100 | 2,133 | — |
| RWS | HIT | 120 | HIT | 2,940 | 2,303 | — |
| Aguila | SP | 117 | SP | 2,940 | 2,245 | — |
| Black Hills | Gold | 117 | ELD-X | 2,940 | 2,245 | — |
| Sako | Gamehead | 120 | SP | 2,940 | 2,303 | — |
| Nosler | Trophy Grade | 100 | Partition | 2,910 | 1,880 | — |
| Norma | Oryx | 129 | Oryx SP | 2,900 | 2,409 | — |
| Lapua | Naturalis | 100 | Naturalis | 2,900 | 1,867 | — |
| Norma | TipStrike | 100 | TipStrike | 2,900 | 1,867 | — |
| PPU | Rifle | 100 | SP | 2,900 | 1,867 | — |
| Norma | Oryx | 100 | Oryx | 2,900 | 1,867 | — |
| RWS | Rifle | 100 | ID Classic | 2,900 | 1,867 | — |
Velocities are manufacturer-stated (test-barrel). Discontinued loads dimmed.
Suitable powders
1 reloading powder listed for .257 Roberts, 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 .257 Roberts
12 models in the database chamber .257 Roberts. Browse all →
Lineage
Connected reference
History
Originated as wildcat in 1920s by Ned Roberts and A.O. Niedner, necking down 7x57 Mauser. Remington commercialized in 1934. Unfortunately, Remington used conservative loads due to weak surplus Mauser actions on market, neutering its performance. Proper handloads or +P ammunition show its true potential. Never achieved massive popularity but has devoted following. One of the most beloved wildcats-turned-commercial.
FAQs
- What twist rate does .257 Roberts use?
- .257 Roberts typically uses a 1:10 twist rate.
- What bullet diameter is .257 Roberts?
- .257 Roberts uses a 0.257″ (6.528 mm) diameter bullet.
- Is .257 Roberts still in production?
- .257 Roberts is active; typical availability is moderate.
- What is .257 Roberts used for?
- .257 Roberts is primarily used for hunting, target.
- What is .257 Roberts based on?
- .257 Roberts is derived from the 7x57mm Mauser case.
- What are the best powders for .257 Roberts?
- Reloading powders commonly listed for .257 Roberts include Reloader 17.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 32 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →