Caliber Description
The 6mm GT (standing for “George and Tom”) is a relatively recent addition to the world of precision shooting cartridges, having been introduced around 2019. Developed by George Gardner, the founder of GA Precision, and Tom Jacobs, a renowned benchrest shooter, the 6mm GT aimed to bridge the gap between the .243 Winchester, 6mm Creedmoor, and the widely popular 6mm Dasher and 6mm BRA. The goal was to create a cartridge with inherently high accuracy, excellent velocity, and ease of reloading, while maintaining reliable feeding in magazine-fed rifles common in Practical PRS (Precision Rifle Series) and long-range shooting competitions. The 6mm GT’s design, featuring a short, efficient case with a 35-degree shoulder, offers optimal powder capacity for modern 6mm bullets while creating consistent ignition with small or large rifle primers.
In terms of applications, the 6mm GT has rapidly gained a following among competitive precision rifle shooters, especially those active in PRS and NRL matches. Its efficient case design offers a perfect balance between recoil and ballistic performance, making it a strong contender for matches where high round count and staying on target are essential. The 6mm GT is praised for its low recoil impulse compared to larger 6.5mm or 7mm cartridges, which enables faster follow-up shots and easier spotting of impacts. Its compatibility with standard short-action receivers and overall cartridge length makes it ideal for magazine feeding, a key consideration in timed competitions. While it originated in the precision shooting arena, its capabilities also make it suitable for tactical and varmint hunting scenarios where precise, long-range shots are required.
For target species, the 6mm GT is most popular among shooters targeting steel or paper in competitive environments, but its ballistic profile also makes it effective for hunters pursuing small to medium game. It is especially efficient for varmints like coyotes, marmots, and prairie dogs, where the combination of speed and accuracy delivers devastating terminal performance at distance. The high ballistic coefficients achievable with modern 6mm bullets ensure that wind drift is minimized, making the 6mm GT a solid option for open-country hunting. However, for larger game such as deer, bullet choice and shot placement remain critical, as the 6mm projectiles do not carry the same energy as heavier caliber options.
Reloaders will appreciate the typical bullet weights for the 6mm GT, which usually fall between 105 and 115 grains, with 107 and 110-grain projectiles being especially popular due to their high ballistic coefficients and proven accuracy. The efficient case design allows for velocities between 2,850 and 3,100 feet per second, depending on load and barrel length, offering both flat trajectory and manageable recoil. The cartridge’s case life has been reported as excellent, particularly for moderate loads, and brass for the GT is now available from several high-quality manufacturers. Compatible powders for the 6mm GT include Varget, H4350, and Reloder 16, among others—allowing for flexibility and customization in load development. The 6mm GT’s balance of manageable pressure, available components, and competitive ballistics positions it as a prime choice for reloaders seeking to extract every ounce of precision from their shooting platforms.
Popular Load Recipes
- 6mm GT, 105 gr Hornady BTHP, 36.5 gr Varget, CCI 450 primer, Hornady brass, COAL 2.800"
- 6mm GT, 109 gr Berger LR Hybrid, 35.8 gr Varget, CCI BR4 primer, Alpha brass, COAL 2.790"
- 6mm GT, 105 gr Berger Hybrid, 37.2 gr H4350, CCI 450 primer, Hornady brass, COAL 2.815"
- 6mm GT, 108 gr Hornady ELD-M, 36.0 gr Varget, CCI 450 primer, Alpha brass, COAL 2.800"
- 6mm GT, 110 gr Sierra MK, 37.0 gr H4350, CCI 450 primer, Hornady brass, COAL 2.810"
- 6mm GT, 105 gr Berger Hybrid, 37.1 gr H4350, Federal 205M primer, Alpha brass, COAL 2.815"
- 6mm GT, 109 gr Berger LR Hybrid, 36.4 gr Varget, CCI 450 primer, Hornady brass, COAL 2.800"
- 6mm GT, 108 gr Berger BT Target, 36.2 gr Varget, CCI 450 primer, Hornady brass, COAL 2.790"
**Note: Always cross-check load data with up-to-date published sources and start at least 10% below posted charge weights.
Cost per Reloaded Round
Let's estimate the cost difference per round between reloading 6 mm GT and purchasing factory ammunition.
Factory 6 mm GT ammunition (as of 2024) is limited but available, such as Hornady 6 mm GT 109 gr ELD Match, at an average retail price of about $55 to $60 per box of 20 rounds. This yields a per-round cost of about $2.75 to $3.00.
Reloading costs:
- Brass: Lapua 6 mm GT brass costs about $120 for 100 ($1.20 per case, but reusable many times; assume 10 uses, so $0.12 per round)
- Primer: $70 per 1000, so $0.07 per primer
- Powder: 40 grains per round, 7000 grains per pound, one pound ($50) yields 175 charges, so $0.29 per round
- Bullet: Hornady 109 gr ELD-M, about $50 per 100, so $0.50 per round
Total per round to reload:
Brass: $0.12
Primer: $0.07
Powder: $0.29
Bullet: $0.50
Total: $0.98
Factory per round (using $2.90 as average): $2.90
Reload per round: $0.98
Savings per round: $2.90 - $0.98 = $1.92
You save around $1.92 per round by reloading 6 mm GT compared to buying factory ammunition.
Technical Specifications
Safety Standard / Application
SAAMI / Rifle Caliber
Most Suitable Bullet Weights
59 - 111 Grains
Case Capacity / Average Charge
43.2 Grains of Water / 34 Grains
Average Muzzle Velocity / Energy
3012 fps / 1681 ft-lbf
Case Length / Max. C.O.L
1.725'' / 2.515''