Lindcott Armory Rifle · SAAMI
6GT
Purpose-built PRS competition cartridge designed for optimal performance with heavy-for-caliber 6mm bullets.
- Caliber
- 0.243″ · 6.172 mm
- Introduced
- 2021
- Case
- Rimless
- Parent
- 6.5x47mm Lapua
- Primary use
- Competition, Target
- Status
- Active
- Introduced
- 2021
- Type
- Rifle
- Origin
- United States
- Inventor
- George Gardner / Tom Jacobs
- Manufacturer
- Hornady / Various
- Standard
- SAAMI
- Status
- Active
- Availability
- Common
- Case capacity
- 46.5 gr H₂O
- Twist (typical)
- 1:7.5
- Primer
- Small Rifle
- Case type
- Rimless
- Max pressure
- 63,000 psi
- Eff. range
- 1200 yd
- Max range
- 3500 yd
- Recoil
- 5–8 ft·lb
Ballistics
Real trajectory computed from a representative load — Hornady ELD Match 109 gr, 2,959 fps, BC 0.277 G7 · 100 yd zero.
| Range | Velocity | Energy | Drop (in) | Drop (MOA) |
|---|---|---|---|---|
| 0 yd | 2958 | 2118 | -1.5″ | — |
| 100 yd | 2791 | 1884 | 0.0″ | 0.0 |
| 200 yd | 2627 | 1670 | -3.0″ | -1.4 |
| 300 yd | 2468 | 1474 | -11.0″ | -3.5 |
| 400 yd | 2315 | 1297 | -24.8″ | -5.9 |
| 500 yd | 2168 | 1137 | -44.9″ | -8.6 |
| 600 yd | 2024 | 992 | -72.6″ | -11.6 |
| 700 yd | 1886 | 861 | -108.8″ | -14.8 |
| 800 yd | 1752 | 743 | -154.7″ | -18.5 |
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 6GT 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 ⌀ | 6.17 | 0.243 | ✓ |
| Neck ⌀ | 6.93 | 0.273 | ✓ |
| Shoulder ⌀ | 11.66 | 0.459 | ✓ |
| Shoulder angle | 35° | — | ✓ |
| Base ⌀ | 11.95 | 0.470 | ✓ |
| Rim ⌀ | 11.96 | 0.471 | ✓ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.37 | 0.054 | ~ |
| Neck length | 7.32 | 0.288 | ≈ |
| Case length | 43.82 | 1.725 | ✓ |
| Overall length | 67.06 | 2.640 | ~ |
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. 6GT is highlighted below.
Factory loads
In production — 14 active loads across 11 brands. Top 14 shown.
| Brand | Load | Grain | Bullet | FPS | ft·lb | BC |
|---|---|---|---|---|---|---|
| Hornady | ELD Match | 109 | ELD-M | 2,959 | 2,119 | 0.277 G7 |
| Alpha Munitions | OTM | 109 | OTM | 2,959 | 2,119 | — |
| Prime Ammunition | OTM Match | 109 | OTM | 2,959 | 2,119 | — |
| Berger | OTM Hybrid Target | 109 | Hybrid OTM | 2,959 | 2,119 | — |
| Hornady | ELD-M | 105 | ELD-M | 2,910 | 1,974 | — |
| ADG | OTM Match | 109 | OTM BTHP | 2,900 | 2,035 | — |
| Peterson Cartridge | OTM Match | 109 | Berger OTM Hybrid | 2,900 | 2,035 | — |
| Black Hills | OTM | 105 | OTM | 2,900 | 1,960 | — |
| SIG Sauer | Elite OTM Match | 109 | OTM BTHP | 2,900 | 2,035 | — |
| SIG Sauer | Elite | 105 | OTM | 2,900 | 1,960 | — |
| Lapua | Scenar | 105 | Scenar | 2,900 | 1,960 | — |
| Federal | Gold Medal | 107 | Hybrid | 2,900 | 1,998 | — |
| Nosler | RDF | 107 | RDF | 2,880 | 1,970 | — |
| Berger | Hybrid | 109 | Hybrid | 2,860 | 1,979 | — |
Velocities are manufacturer-stated (test-barrel). Discontinued loads dimmed.
Suitable powders
1 reloading powder listed for 6GT, 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 6GT
5 models in the database chamber 6GT. Browse all →
Lineage
Connected reference
History
Developed by George Gardner of GA Precision and Tom Jacobs of Vapor Trail Bullets specifically for Precision Rifle Series competition in semi-automatic rifles. The goal was a cartridge that fed reliably from AR-10 pattern magazines while shooting the heaviest, highest-BC 6mm bullets with less recoil than 6mm Creedmoor. Submitted to SAAMI and standardized in 2021 — unusually fast adoption for a competition-born cartridge.
FAQs
- What twist rate does 6GT use?
- 6GT typically uses a 1:7.5 twist rate.
- What bullet diameter is 6GT?
- 6GT uses a 0.243″ (6.172 mm) diameter bullet.
- Is 6GT still in production?
- 6GT is active; typical availability is common.
- What is 6GT used for?
- 6GT is primarily used for competition, target.
- What is 6GT based on?
- 6GT is derived from the 6.5 Creedmoor case.
- What are the best powders for 6GT?
- Reloading powders commonly listed for 6GT include LT-32.
Sources & provenance
- StandardSAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawingsarchived
- SecondaryNRA — Shooting Sports USA (SSUSA) — What is 6 mm GT? · parent_cartridgearchived
- Secondary6GT — New Cartridge, Alpha Brass (AccurateShooter Forum) · parent_cartridge
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 14 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →