The Ultimate Reloader YouTube Channel, owned by Gavin Gear, has some of the best content related to reloading, building rifles, testing gear, comparing cartridges, and hunting. Gavin recently posted an excellent video highlighting a 6GT build with an MDT ACC Chassis and conducted load development resulting in first-round hits at 1,000 yards. Before we get into the build, let's talk about the 6GT Cartridge.
GENESIS OF 6MM GT
Excerpt from "Building a 6mm GT for Competition", published on October 21st, written by Willam Maxwell. Inside MDT.
As with all things, precision rifle shooting isn't immune to evolution – especially with its growing popularity. First, it was the .30 calibers, then it went to the 6.5s, and now we're all about sending 6mm bullets faster and faster. 6.5 Creedmoor got necked down to 6mm Creedmoor, 6.5x47mm Lapua got necked down to 6x47mm Lapua, and PRS competitors even started using benchrest cartridges like 6mm BR Norma. Except for the Creedmoor class of cartridges, you will be restricted to handloading, and the 6BR made that relatively simple: throw some Varget behind a 105-grain bullet, and you're off to the races, sort of.
The BR was not designed to be shot out of bolt-action rifles but meant to be single-fed. That led to improvements like 6BRA(Ackley Improved), 6BRX, and the 6mm Dasher more recently. The improvements to the case design, in conjunction with modified AICS magazines with 'BR Spacers', were supposed to fix the feeding issues. However, by all accounts, the cartridge was still finicky in a repeater at best, and getting quality brass was challenging.
Enter George Gardner of GA Precision and Tom Jacobs of Vapor Trail Bullets.
They set out to find a middle ground between the BR, its variants, and the Creedmoor for competition use. The goal was to shoot a 105-115 grain high B.C. projectile at speeds up to 3050 fps with low recoil and single-digit standard deviations, specifically using Varget (Other powders like H4350 work just as well, or in some cases better)
BUILD GAVIN'S 6MM GT
Gavin's 6mm GT build is detailed in this video!
6MM RESOURCES FROM MDT
- Loading 6MM ARC and .223 Remington with A Dillon Progressive Press
- HORNADY 6MM ARC For Competition
- Analysis: 6MM BR NORMA
- Loading 6GT with Hodgdon H4350
- Building a 6mm GT for Competition
- 6mm GT Load Development