Sunday Gunday 2023: Gavin’s 6GT Shines in Snowy Northwest

For the very first day of 2023 we present a precision rifle built with a relatively new cartridge — the 6GT. Developed by George Gardner of G.A. Precision and Tom Jacobs of Vapor Trail Bullets, the 6GT was designed to have the efficiency of a 6mm Dasher without the need for case forming. It was also designed with a longer case body so it feeds better from magazines. Even with the added capacity, the 6GT is still very efficient, and can achieve good velocities with less powder than a 6mm Creedmoor.

Today’s Sunday Gunday feature rifle was smithed and tested by Gavin Gear of UltimateReloader.com. Gavin did all the gunsmithing — chambering the barrel, fitting the muzzle brake, and even laser engraving the barrel. In building this 6GT rifle, Gavin used top-tier components: BAT TR action, Krieger 28″ 1:7.5″-twist 4-groove 6mm barrel, TriggerTech Diamond Rem 700-compatible trigger, and Area 419 Hellfire Muzzle Brake. The barreled action was then fitted in a handsome and rugged MDT ACC Chassis. On top is a Zero Tech 4.5-27×50mm FFP Trace Advanced scope in 30mm Hawkins Precision high rings.

We recommend you watch the video above — it covers the rifle build, load development, and then features some remarkable shooting sequences across snowy hills in the Pacific Northwest. Gavin’s team actually used a drone to capture overhead footage of the location.

After developing a promising load with Berger 109gr LRHT bullets, Varget powder, and Alpha brass, Gavin literally headed for the hills to test his new rifle at longer ranges, shooting from bipod. His load had shot well under half-MOA at 100 yards in testing so he was hoping he could hit multiple steel targets positioned at 340 yards, 760 yards, and 1000 yards. Indeed he did, proving the rifle’s great accuracy and Gavin’s fine trigger-pulling skills. You can see the hits at these time points in the above video:

340 Yards — 18:15 time | 760 Yards — 19:00 time | 1000 Yards — 19:54 Time

Gavin’s 6GT Hit Highlights on Steel out to 1000 Yards

Building Gavin’s 6GT Precision Rifle

Gavin Gear did all the gunsmithing on this project, using his own Precision Matthews TL-1660 lathe for the chambering with an Alpha carbide 6GT reamer. The barrel work took about four hours total. Shown below is the reamer cutting the chamber, which was finished with a 0.170″ freebore and 0.270″ neck diameter. For other brands of brass you might want the chamber to have a larger 0.272″ neck diameter.

Chambering the Krieger barrel with Alpha carbide 6GT reamer, 0.170” freebore, .270″ neck diameter.

This project when smoothly, with Gavin able to install the barreled action in the MDT Chassis and fit the buttstock in an hour or so. So total build time was about five hours. One nice “finishing touch” on the project was laser engraving the 28″ Krieger barrel — a process you can see in the video below.

Laser engraving of Krieger 28″ barrel.

About the 6GT — Sort of a 6 Dasher on Steroids

6GT Cartridge Design Features

The 6GT was designed to have an optimal length and capacity for mag-fed PRS/NRL tactical rifles. The 6GT is longer than a 6mmBR and 6 Dasher, but shorter than a 6mm Creedmoor and 6.5×47 Lapua. That gives the 6GT ample case body length to feed reliably from a magazine, while the case capacity is sufficient to run popular powders at reasonable pressures. It has a 35-degree shoulder angle.

On paper the 6GT seemed like the perfect cartridge for PRS- and NRL-style centerfire competition. It has the low recoil of a 6 Dasher, with good feeding and mag compatibility. With the 6GT, a competitor can push 6mm 105gr bullets at 3000+ FPS or run heavier bullets at ~2950 FPS. With this 28″ Krieger barrel, Gavin actually achieved 3004 FPS running 109gr Bergers.

On the G.A. Precision website, the qualities of the 6GT are listed as follows:

Loading for the 6GT

Gavin started with quality Alpha Munitions brass. The cases were then annealed with an AMP Annealer and trimmed to length with a Henderson powered trimmer (see video below). After sizing with a Forster Co-Ax press, Federal SR Primers were seated using a Primal Rights competition seater. Next the powder was measured with an A&D FX120i force restoration scale. Finally, the Berger 109gr LR Hybrid Target bullets were seated with a Forster Micrometer die, again using the smooth Forster Co-Ax press.

Initial Load Testing with Berger and Hornady Projectiles

Before it got cold and snowy, Gavin did load development, shooting from a bench with a Sinclair front rest. The Krieger cut-rifled barrel was accurate right from the start and Hodgdon Varget powder proved to be a very good choice for the 6GT.

Gavin’s 6GT boasts a MDT ACC short action chassis with SRS-X Elite buttstock, vertical grip, and MDT CKYE-POD Bipod.

Gavin did initial load testing with both Hornady 110gr A-Tip Match and Berger 109gr Long Range Hybrid Target bullets. The Berger 109gr LRHT bullets were the most promising. A variety of charge weights were tested, with Gavin settling on 34.6 grains of Varget. This delivered fine accuracy with a 3004 FPS muzzle velocity. Group size measurements with this load are shown in the chart. At 100 yards, four three-shot groups averaged 0.361 MOA, and the rifle produced a nice 0.387 MOA (0.405″) five-shot group.

Coming Soon — Ultimate Reloader Rifles Business

Gavin Gear is in the process of opening his own gunsmithing business. He will be offering a variety of custom-built rifles for multiple disciplines — hunting, PRS/NRL, ELR, and other competitive disciplines. Gavin explains: “Ultimate Reloader is gearing up to do custom rifle work for the general public starting (hopefully) in Spring 2022. We will most likely start with complete custom rifle builds using parts from our inventory. We will focus on high-end, bolt-action rifle builds and gunsmithing, primarily Remington 700 and clones. We will entertain limited gunsmithing work outside of complete builds (i.e. chambering, muzzle threading).

If you are interested, go to Rifles.UltimateReloader.com, then fill out the Waiting List Form to receive more information.

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Tags: 6GT Cartridge, Alpha Brass, Gavin Gear, George Gardner, Krieger Barrel, Ultimate Reloader