Handloader|February 2021
Layne Simpson
Wildcat cartridges have been developed for many different reasons. Some produced velocities higher than was possible with factory-loaded cartridges. Some were more accurate. Others were developed for use in certain firearms. The 6mm GT may be the only wildcat cartridge developed for the use of a specific combination of powder type and bullet weight range.

Created by George Gardner and Tom Jacobs, the 6mm GT was designed to use Varget powder for pushing match-grade bullets weighing 105 to 110 grains at velocities ranging from 3,000 fps to 3,100 fps. In addition to owning GA Precision, George is an avid participant in Precision Rifle Series (PRS) competition, where steel targets are engaged out to 1,000 yards and sometimes farther. Tom is a champion 600- and 1,000-yard benchrest competitor.

The 6mm GT is similar to the earlier 6mm Dasher designed by Dan Dowling and Al Ashton for 100- and 200-yard benchrest competition. The Dasher is basically the 6mm BR Remington case with the shoulder moved forward for additional powder capacity and shoulder angle increased to 40 degrees. It pushes the heavier match bullets about 200 feet per second faster than the 6mm PPC.

The 6mm Dasher has proven to be equal to the 6mm PPC in accuracy, and while it has won its share of matches in short-distance benchrest competition through the years, it has not proved to be a serious threat there. But due to its ability to launch heavier bullets faster while being easier on barrel accuracy life than bigger cartridges, it has become one of the more popular cartridges used by competitors in PRS, F-Class and long-distance benchrest competitions.

I asked George Gardner why he thinks the 6mm GT is a better choice than the 6mm Dasher for long-distance competitive shooting. For starters, he described the 6mm Dasher as too short to reliably feed from high-capacity magazines commonly available for the .308 Winchester, and when loaded to maximum chamber pressure, it struggles to reach his desired velocity range of 3,000 to 3,100 fps with bullets weighing from 105 to 110 grains. Using a case with a bit more powder capacity would solve that problem.

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