The 6mm GT (aka 6GT) cartridge was conceived as a “bigger Dasher” for PRS and NRL competition. The 6mm GT’s creators wanted 6mm Dasher accuracy and moderate recoil delivered via a cartridge with a slightly longer case body for better mag-feeding, longer neck for seating flexibility, and more moderate pressures. So far the 6GT has performed very well in PRS competition. Today’s story is a bit different — this is about an experiment — running a 6mm GT in an F-TR type rifle. Understand that, under current NRA rules, you may only shoot .223 Rem (5.56×45) or .308 Win (7.62×51), in official, sanctioned F-TR competition, but the 6GT is fine for F-Open. Mike McCasland wanted to see the potential of the cartridge for long-range target shooting, so he put a 6mm GT-chambered Bartlein barrel on a nice custom rifle with McMillan XIT stock and Kelbly F-Class Panda action. The results were impressive.
6mm GT — New Cartridge with Multi-Discipline Potential
Story by Mike McCasland, Texas Precision
The 6mm GT began garnering attention within PRS circles in early 2019. It promised to shoot 105-110gr 6mm bullets at 2950-3000 FPS, yet not suffer from mag-feed issues sometimes found with 6mmBR variants such as the 6 Dasher, 6BRX, and 6BRA. Moreover, since it burned less powder, the 6mm GT promised increased barrel life compared to the 6mm Creedmoor or 6XC. The 6mm GT case size should still work with the accurate powders in the Varget burn-range. I found the 6GT also worked great with H4350.
As someone who aspired to building a repeater and jumping into the PRS game, and had a spare F-TR rifle sitting around, I thought it would be fun to build up a 6mm GT to see if there was any merit to the hype. My smith, Wes Ripley of RIP Precision in Texas, builds a lot of PRS rigs, and already had the reamer on hand (a 0.120″ freebore variant).
Whidden Gunworks had some 6mm GT FL bushing die kits in stock, so I figured why not see what all the fuss was about? At the very least I could play around with the 6mm GT in F-Open Class at local club matches to see how it compared to the 6BRA, 6 Dasher, and other popular 6mm cartridges.
Click image to see video comparison of multiple 6mm cartridges by Quarter Minute Magnums.
How the Project Got Started with Backup F-TR Rig
My 6mm GT build really started as a project spawned purely from COVID-19 Isolation boredom. This rifle primarily serves as a backup F-TR gun, and it had been relegated to performing some load development on .308 barrels, so I could spin new ones on my main match rifle. The only problem was, I had run out of .308 barrels that needed load development. So, I basically had an ideal test platform just collecting dust in the safe. All I needed was a 6mm GT-chambered barrel, since (like the 6mmBR) the 6mm GT works in a short action with a .308 Win-sized bolt-face.
6mm GT Rifle Specifications:
Action: Kelbly Panda F-Class SA RB/RP
Stock: McMillan XIT with RAD 2A
Barrel: 30″ 5R Bartlein 1:7.5″-Twist, HV Contour
Scope: Vortex Golden Eagle 15-60x52mm
Trigger: Jewell Benchrest, about 2 ounces
Bipod: Phoenix Precision
Mike McCasland reports: “I have used both Hornady and Alpha brass in this rifle and haven’t noticed much difference between the two. I will say that my batch of Alpha brass was slightly softer than Alpha brass I’ve used in other calibers; you could feel a difference when neck turning cases. I’m unsure if that’s a batch issue, or something specific to their 6mm GT brass as a whole. As far as performance, there was little discernable difference. Oddly enough, the Hornady brass seemed to have slightly less case capacity than the Alpha; with most other cartridges it’s the other way around.”
In this video, George Gardner of GA Precision talks about the 6mm GT cartridge which he helped develop.
POWDERS — The 6mm GT was designed with Hodgdon Varget in mind, and that popular powder works exceedingly well in this platform. That said, the 6mm GT can work with a wide variety of powders, some yielding better performance than Varget.
I’ve tried a multitude of powders during my initial 6mm GT load development: Varget, Shooters World Precision, RL16, VV N140, H4350, and RL-15 to name a few. In my barrel, Hodgdon H4350 seems to deliver the best velocity/accuracy combination. SD and ES also seemed to be the lowest with H4350.
Load Development for the 6mm GT — Many Powders Tested
BULLETS — The most common 0.120″ freebore chamber allows for the majority of high-BC 6mm projectiles found in both F-Class and PRS. I had good luck with the pointed 107gr Sierra Match Kings (SMK), as well as the 110gr Hornady A-Tips in my rifle. For those looking to run the heavier 112-115 grain 6mm offerings, I believe GAP designed a 0.160″ freebore reamer that gets those bullets out of the neck/shoulder junction. Shown below is the 0.120″ freebore JGS reamer print:
SUMMARY — Good Cartridge with Much Potential
Generally speaking, I think the 6mm GT is a good little round. Some may not subscribe to this theory, but I believe some cartridges are inherently easier to tune than others. I’m not sure the 6mm GT is as easy-to-tune as a 6mmBR, 6 Dasher, or 6 BRA, but I don’t think it lags that far behind.
With relatively little trouble, I was able to find loads with both Varget and H4350 that would consistently shoot very well — 0.2 to 0.3 MOA. Moreover, I found the 6GT cartridge lives up to the velocity claims made by G.A. Precision. I was easily able to push the 110gr A-Tips to 2950 FPS, and the 107gr SMKs to low 3000 FPS range without any pressure signs, or unnecessary wear and tear on the brass.
As a fun test, I ran my 6mm GT rifle in a local 1000-yard F-Class match with the 110gr A-Tips, just to see just how well they would perform. Although wind conditions of the day and some E-Target issues prevented my 6mm GT rig from getting the better of the larger 7mm and .30-Cal rifles, the 6mm GT proved itself an accurate little round at distance. Here is a 1000-yard ShotMarker target:
After putting several hundred rounds through my 6mm GT rifle, I anticipate building another 6GT on a repeater action to give PRS a try. I think if you are looking for a dual-purpose rifle that can run tactical matches (with 100% feeding reliability), and can also be used for mid-range, F-Open Class competition, the 6mm GT would be a very good option.
About the author, Mike McCasland:
Mike McCasland is an avid shooter who competes regularly in F-Class matches. Based in Texas, Mike is the creator of the Texas Precision YouTube Channel. There you’ll find many videos covering reloading, gun projects, and marksmanship. Mike has done some notable product reviews including a comparison test of Micrometer Competition Seating Dies. To access Mike’s YouTube Channel, CLICK HERE.
This week, Shooting USA TV spotlights the 2022 GAP Grind, the largest PRS Pro-Am Tactical match with nearly 400 competitors. The 10th Annual GA Precision/Elite Tactical GAP Grind PRO-AM was held September 30 through October 2, 2022 at the K&M Shooting Complex in Tennessee. The GAP Grind, the largest, most popular PRS match in the world, drew nearly 400 amateur and pro shooters from across the USA and from many other nations. Recognized as the premier PRO-AM precision rifle match with both individual and team competition, the GAP Grind has introduced thousands of new shooters to the sport since its inception. It was great to see the GAP Grind successfully mark its 10th Anniversary.
SHOW TIMES: This Shooting USA Episode airs Wednesday, November 16, 2022 at 9:00 PM Eastern and Pacific; 8:00 PM Central. If you miss the regular broadcast, you can stream the show at any time on Vimeo for $0.99 per episode.
In this video Eagle Eye Shooting Shares Highlights from the 2022 GAP Grind
Excellent Attendance at 10th Annual GAP Grind Event
The year’s largest PRS match drew hundreds of attendees, and more than 80,000 rounds were fired throughout the three-day event. In addition to competition stages, the GAP Grind featured a vendor area, live music and entertainment. Bushnell gave out $5,000 to the top place finishers and added over $5,000 worth of product to the prize table. Trophies were awarded to the top 5 teams, top 5 professionals, and to the top 5 amateurs.
Lots of Action, with 20+ Stages
The GAP Grind is a challenging, “high tempo” match with minimal down-time between stages. Over the course of 20+ stages, competitors will fire 200+ shots at a variety of steel, paper, moving, and reactive targets out to 1,200 yards. Targets vary in size/difficulty based on the shooter’s position, distance, and time allotted. Most stages include “stressors” — i.e. time limits or required movement(s).
This extensive, 45-minute video shows many of the 2022 GAP Grind Stages
GAP Grind Pro-Am Format — Seasoned Shooters Help Newcomers
The GAP Grind typically attracts nearly 400 competitors — half experienced shooters and the other half newcomers to the sport. The key to growing the shooting sports is attracting new shooters. The best way to bring in “new blood” seems to be the Pro-Am type format. At the GAP Grind, experienced shooters share their knowledge and guide the new shooters through the competition.
GAP Grind Hardware
You’ll find the latest and greatest PRS hardware at the GAP Grind. Over the past few seasons, most top competitors have “stepped down” from the 6.5/6mm Creedmoor to the smaller, more efficient 6mm Dasher, 6BRA, 6 GT and other 6mm cartridges. The Dasher offers excellent accuracy with less recoil than the 6.5 Creedmoor. Also, many competitors will be switching to the impressive new Zeiss FFP LRP S3 and S5 scopes in the months ahead.
The 10th Annual GA Precision/Elite Tactical GAP Grind PRO-AM was held September 30 through October 2, 2022 at the K&M Shooting Complex in Tennessee. The GAP Grind, the largest, most popular PRS match in the world, drew hundreds of amateur and pro shooters from across the USA and from many other nations. Recognized as the premier PRO-AM precision rifle match with individual and team competition, the GAP Grind has introduced thousands of new shooters to the sport since its inception. It was great to see the GAP Grind successfully mark its 10th Anniversary.
In overall standings, Daniel Hereid (photo below) finished first among Pro shooters, while Toby Phillips was top Amateur Overall. The Top Five Pros and Amateurs, along with Top Five Teams are listed overall below. There were four hardware-based divisions: Gas Gun, Open, Production, and Tactical. Pro shooter Robert Brantley led the Tactical Division and pro Ryan Kerr topped the Production Division. Notably, both Brantley and Kerr were running Bushnell Elite Tactical XRS3 riflescopes.
1st – Daniel Hereid
2nd – Francis Colon
3rd – Chad Heckler
4th – Chris Simmons
5th – Nathan Cushman
Top 5 Amateurs:
1st – Toby Phillips
2nd – Tyler Yauch
3rd – Jeff Johnson
4th – Ryder Smith
5th – Caleb Purinton
Top 5 Pro/Am Teams:
1st – Tate Streater + Toby Phillips
2nd – Chad Heckler + Jacob Strutt
3rd – Joey McConnell + Ryder Smith
4th – Daniel Herald + Vince Yarling
5th – Troy Livesay + Rick Lovely
Excellent Attendance at 10th Annual GAP Grind Event
The year’s largest PRS match drew hundreds of attendees, and more than 80,000 rounds were fired throughout the three-day event. In addition to competition stages, the GAP Grind featured a vendor area, live music and entertainment. Bushnell gave out $5,000 to the top place finishers and added over $5,000 worth of product to the prize table.
The PRS website explains how the GAP Grind is conducted and scored: “Competitors will compete as individuals and as a team; scores will be maintained for both. Trophies will be awarded to the top 5 teams, top 5 professionals, and to the top 5 amateurs. Each team member will shoot a similar course of fire with slight modifications for the Amateurs. Professionals will shoot first and unassisted. The Amateur will shoot each stage with the Professional’s assistance. Scores for both days will count toward team standings and individual standings. This allows Precision Rifle Series shooters the ability to earn 2 day PRO Series points for this match. Amateurs … may earn PRS Regional Series points.”
In this video Eagle Eye Shooting Shares Highlights from the 2022 GAP Grind
Lots of Action, with 20+ Stages
The GAP Grind is a challenging, “high tempo” match with minimal down-time between stages. Over the course of 20+ stages, competitors will fire 200+ shots at a variety of steel, paper, moving, and reactive targets out to 1,200 yards. Targets vary in size/difficulty based on the shooter’s position, distance, and time allotted. Most stages include “stressors” — i.e. time limits or required movement(s).
This extensive, 45-minute video shows many of the 2022 GAP Grind Stages
“Sponsoring the GAP Grind is always a privilege, and this 10-year mark made it especially fun,” said Matt Rice, Bushnell senior media relations manager. “GAP Grind is all about giving both experienced and new shooters a welcoming place to test and hone their skills, and our partners at K&M, G.A. Precision and PRS have done a fantastic job of making that goal a reality.”
This week, Shooting USA TV spotlights the 2021 GAP Grind, the largest PRS Pro-Am Tactical match with nearly 400 competitors. The 2021 GAP Grind/Bushnell Pro/Am took place in October at the K&M Precision Shooting Complex in Finger, Tennessee. The 3-day event, the biggest PRS match of the year, included professional and “amateur” classes with both individual and team competition. Here are highlights from the 2021 event in this Area419-produced video:
GAP Grind 2021 in Tennessee:
SHOW TIMES: This Shooting USA Episode airs Wednesday, March 30, 2021 at 9:00 PM Eastern and Pacific; 8:00 PM Central. If you miss the regular broadcast, you can stream the show at any time on Vimeo for $0.99 per episode.
The GAP Grind is held at the impressive K&M Shooting Complex in Tennessee:
GAP Grind 2022 INFO: If you are interested in competing in the 2022 GAP Grind, Registration Opens June, 3 2022. The 2022 GAP Grind runs September 30 through October 2, 2022.
Lots of Action, with 20+ Stages
The GAP Grind is a challenging, “high tempo” match with minimal down-time between stages. Over the course of 20+ stages, competitors will fire 200+ shots at a variety of steel, paper, moving, and reactive targets out to 1,200 yards. Targets vary in size/difficulty based on the shooter’s position, distance, and time allotted. Most stages include “stressors” — i.e. time limits or required movement(s).
The GAP Grind typically attracts over 300 competitors — half experienced shooters and the other half newcomers to the sport. The key to growing the shooting sports is attracting new shooters. The best way to bring in “new blood” seems to be the Pro-Am type format. At the GAP Grind, experienced shooters share their knowledge and guide the new shooters through the competition.
Great video shows K&M Complex — overhead and action shots — Click II pause to halt:
GAP Grind Hardware
You’ll find the latest and greatest PRS hardware at the GAP Grind. Notable in 2021 was the fact that many top competitors “stepped down” from the 6.5/6mm Creedmoor to the smaller, more efficient 6mm Dasher, 6BRA and other 6mm cartridges. The Dasher offers excellent accuracy with less recoil than the 6.5 Creedmoor. Also, many top shooters are now running Kahles optics and we predict will be running the new Zeiss FFP scopes in 2022. Photo by Shelley Giddings.
This week, Shooting USA TV spotlights the 2021 GAP Grind, the largest PRS Pro-Am Tactical match with nearly 400 competitors. The 2021 GAP Grind/Bushnell Pro/Am took place in October at the K&M Precision Shooting Complex in Finger, Tennessee. The 3-day event, the biggest PRS match of the year, included professional and “amateur” classes with both individual and team competition. Here are highlights from the 2021 event in this Area419-produced video:
GAP Grind 2021 in Tennessee:
SHOW TIMES: This Shooting USA Episode airs Wednesday, December 15, 2021 at 9:00 PM Eastern and Pacific; 8:00 PM Central. If you miss the regular broadcast, you can stream the show at any time on Vimeo for $0.99 per episode.
The GAP Grind is held at the impressive K&M Shooting Complex in Tennessee:
Lots of Action, with 20+ Stages
The GAP Grind is a challenging, “high tempo” match with minimal down-time between stages. Over the course of 20+ stages, competitors will fire 200+ shots at a variety of steel, paper, moving, and reactive targets out to 1,200 yards. Targets vary in size/difficulty based on the shooter’s position, distance, and time allotted. Most stages include “stressors” — i.e. time limits or required movement(s).
The GAP Grind typically attracts over 300 competitors — half experienced shooters and the other half newcomers to the sport. The key to growing the shooting sports is attracting new shooters. The best way to bring in “new blood” seems to be the Pro-Am type format. At the GAP Grind, experienced shooters share their knowledge and guide the new shooters through the competition.
Great video shows K&M Complex — overhead and action shots — Click II pause to halt:
GAP Grind Hardware
You’ll find the latest and greatest PRS hardware at the GAP Grind. Notable in 2021 was the fact that many top competitors “stepped down” from the 6.5/6mm Creedmoor to the smaller, more efficient 6mm Dasher, 6BRA and other 6mm cartridges. The Dasher offers excellent accuracy with less recoil than the 6.5 Creedmoor. Also, many top shooters are now running Kahles optics and we predict will be running the new Zeiss FFP scopes in 2022. Photo by Shelley Giddings.
This weekend, October 1-3, 2021, the 2021 GAP Grind Pro/Am takes place at the K&M Precision Shooting Complex in Tennessee. The 3-day event, the largest and most popular PRS Pro-Am Tactical match, includes professional and “amateur” classes with both individual and team competition. Match organizers expect nearly 400 competitors, who, collectively, will send 80,000+ rounds downrange. And there will be LOTS of prizes — the prize table boasts “hundreds of thousands of dollars in gear” provided by scores of sponsors. And 20+ companies are setting up booths on-site to showcase and sell their products.
Dozens of sponsors make for one of the richest prize tables in all the shooting sports.
The GAP Grind is held at the impressive K&M Shooting Complex in Tennessee:
Lots of Action, with 20+ Stages
The GAP Grind is a challenging, “high tempo” match with minimal down-time between stages. Over the course of 20+ stages, competitors will fire 200+ shots at a variety of steel, paper, moving, and reactive targets out to 1,200 yards. Targets vary in size/difficulty based on the shooter’s position, distance, and time allotted. Most stages include “stressors” — i.e. time limits or required movement(s).
The 2021 GAP Grind will have nearly 400 competitors — half experienced shooters and the other half newcomers to the sport. The key to growing the shooting sports is attracting new shooters. The best way to bring in “new blood” seems to be the Pro-Am type format. At the GAP Grind, experienced shooters share their knowledge and guide the new shooters through the competition.
Great K&M Complex video — overhead and action shots — Click II pause button to halt:
GAP Grind Hardware
You’ll find the latest and greatest PRS hardware at the GAP Grind. Notable in recent seasons was the fact that many top competitors moved down from the 6.5/6mm Creedmoor to the smaller, more efficient 6mm Dasher, 6BRA, 6GT and other 6mm cartridges. The 6mm Dasher offers excellent accuracy with less recoil than the 6.5 Creedmoor. New magazine designs allow very reliable feeding with the shorter cartridges.
This week, Shooting USA TV spotlights the 2020 GAP Grind, the largest and most popular PRS Pro-Am Tactical match. The 2020 GAP Grind/Bushnell Pro/Am took place last October at the K&M Precision Shooting Complex in Finger, Tennessee. The 3-day event, the biggest PRS match of the year, included professional and “amateur” classes with both individual and team competition. Competitors ranged from top professionals to those shooting their first-ever tactical match.
SHOW TIMES: This Shooting USA Episode airs Wednesday, August 4, 2021 at 9:00 PM Eastern and Pacific; 8:00 PM Central. If you miss the regular broadcast, you can stream the show at any time on Vimeo for $0.99 per episode.
The GAP Grind is held at the impressive K&M Shooting Complex in Tennessee:
Lots of Action, with 20+ Stages
The GAP Grind is a challenging, “high tempo” match with minimal down-time between stages. Over the course of 20+ stages, competitors will fire 200+ shots at a variety of steel, paper, moving, and reactive targets out to 1,200 yards. Targets vary in size/difficulty based on the shooter’s position, distance, and time allotted. Most stages include “stressors” — i.e. time limits or required movement(s).
The GAP Grind typically attracts over 300 competitors — half experienced shooters and the other half newcomers to the sport. The key to growing the shooting sports is attracting new shooters. The best way to bring in “new blood” seems to be the Pro-Am type format. At the GAP Grind, experienced shooters share their knowledge and guide the new shooters through the competition.
Great video shows K&M Complex — overhead and action shots — Click II pause to halt:
GAP Grind Hardware
You’ll find the latest and greatest PRS hardware at the GAP Grind. Notable in 2019 was the fact that many top competitors “stepped down” from the 6.5/6mm Creedmoor to the smaller, more efficient 6mm Dasher, 6BRA and other 6mm cartridges. The Dasher offers excellent accuracy with less recoil than the 6.5 Creedmoor. Also, many top shooters are now running Kahles optics. Photo by Shelley Giddings.
BONUS: NRA Membership Discount for Shooting USA Viewers
Shooting USA offers discounts on NRA Memberships. You can save $10 on an annual membership, $15 on a 3-year membership, $25 on a 5-year membership, or $500 on a Life Membership. CLICK HERE for more information on the NRA website.
This Armalite AR-50A1 .50 BMG rifle was modified by G.A. Precision.
If you’re a fan of big boomers, and love shooting steel, then definitely watch this Wide Open Magazine video. This covers a .50 BMG build by our friends at G.A. Precision (GAP). The rifle started as an Armalite AR-50A1 ($3359.00 MSRP). Then GAP fluted the barrel and swapped the factory muzzle brake with a more compact brake from American Precision Arms*. Then, as modified, the entire rig was given a rugged Cerakote finish.
The video has nice background music, great aerial drone footage, and of course some serious firepower. Using Hornady .50 BMG ammo, GA Precision’s George Gardner and his Wide Open friends shoot the big Fifty from the bench as well as prone. Enjoy!
About the .50 BMG Cartridge
The .50 Browning Machine Gun (.50 BMG, aka 12.7×99mm NATO or 50 Browning) is a cartridge developed for the Browning .50 caliber machine gun in the late 1910s, entering official service in 1921. Under STANAG 4383, it is a standard cartridge for NATO forces as well as many non-NATO countries.
John Browning had the idea for this round during World War I in response to a need for an anti-aircraft weapon, based on a scaled-up .30-06 Springfield design, used in a machine gun based on a scaled-up M1919/M1917 design that Browning had initially developed around 1900. According to the American Rifleman: “The Browning .50 originated in the Great War. American interest in an armor-piercing cartridge was influenced by the marginal French 11 mm design, prompting U.S. Army Ordnance officers to consult Browning. They wanted a heavy projectile at 2700 FPS, but the ammunition did not exist. Browning pondered the situation and, according to his son John, replied, ‘Well, the cartridge sounds pretty good to start. You make up some cartridges and we’ll do some shooting’.”
* In the video, George mistakenly says “American Patriot Arms”, but the brake is made by Georgia-based American Precision Arms.
Are you looking to get started in PRS and tactical/practical competitions? Here are three videos that can help you improve your game. These videos feature two top PRS competitors, and George Gardner of G.A. Precision, considered one of the founding fathers of the PRS game. You’ll find other PRS-focused videos on the Long Range Precision Shooters YouTube channel.
PRS Ace Shows Skills Barricade Technique — with POV Video
This first video features 2015 PRS Champion David Preston shooting the PRS Skills barricade. Dave Preston is widely considered the best in the nation running this PRS stage. Dave nearly always shoots 100% with the fastest recorded time. In this video you’ll see him successfully engage all eight shots in under 43 seconds — that’s crazy fast. This includes a POV sequence (4:35 time-mark) showing the actual view through Dave’s scope.
The PRS Skills Barricade is an 8-round, 4-position stage featured at most PRS matches. It’s called a “Skills Stage” as it is run the same way at every national match and gives shooters the ability to compare skill levels based on hit percentage and speed. The target is a 10″ plate at 400 yards. There are four different positions, with two shots each. Most people run this stage in about 70 seconds, some in the mid-60s, while Dave does it in the low 40s!
Know Your Limits PRS Stages — Pro Tips
The Second video showcases how 2018 Oklahoma PPS Champion Clay Blackketter approaches Know Your Limit Stages. With these particular type of stages you have to make judgment calls about your rifle’s accuracy and your ability to hold on target. You can boost your score by shooting the smallest target(s), but you risk losing points if you miss. Clay explains how best to manage a Know Your Limits stage.
Cartridge Choice for PRS and Tactical Competition
Today’s third video reviews many of the different caliber selections popular for PRS-style competition. The video examines pros and cons of various cartridge choices, focusing on accuracy, recoil, mag-feeding, and value for money. This segment features G.A. Precision owner/founder George Gardner.
Most Top PRS shooters are using 6mm catridges these days. These deliver excellent accuracy with lower recoil and cheaper bullet cost. Popular choices include 6 Dasher, 6mm Creedmoor, 6XC, 6-6.5×4 and the new 6GT cartridge, which is sort of a stretched version of a 6mmBR. It has a bit more case length for better feeding, and greater case capacity than a 6BR so you can shoot 105-108 grain bullets at the 2950 fps node.
CLICK HERE for a full write-up on a 6GT rifle build by Mike McCasland (Texas Precision). This includes load development suggestions and a 6GT reamer print. The most common 0.120″ freebore chamber allows for the majority of high-BC 6mm projectiles found in both F-Class and PRS. Mike had good luck with the pointed 107gr Sierra Match Kings (SMK), as well as the 110gr Hornady A-Tips in his rifle, shown below:
Practical Shooter’s Guide
Thinking of getting started in the Practical/Tactical shooting game? Looking for ways to be more stable when shooting from unconventional positions? Then you may want to read Marcus Blanchard’s Practical Shooter’s Guide (A How-To Approach for Unconventional Firing Positions and Training). Unlike almost every “how to shoot” book on the market, Blanchard’s work focuses on the shooting skills and positions you need to succeed in PRS matches and similar tactical competitions. Blanchard provides clear advice on shooting from barricades, from roof-tops, from steep angles. Blanchard says you need to train for these types of challenges: “I believe the largest factor in the improvement of the average shooter isn’t necessarily the gear; it’s the way the shooter approaches obstacles and how they properly train for them.”
The 6mm GT (aka 6GT) cartridge was conceived as a “bigger Dasher” for PRS and NRL competition. The 6mm GT’s creators wanted 6mm Dasher accuracy and moderate recoil delivered via a cartridge with a slightly longer case body for better mag-feeding, longer neck for seating flexibility, and more moderate pressures. So far the 6GT has performed very well in PRS competition. Today’s story is a bit different — this is about an experiment — running a 6mm GT in an F-TR type rifle. Understand that, under current NRA rules, you may only shoot .223 Rem (5.56×45) or .308 Win (7.62×51), in official, sanctioned F-TR competition, but the 6GT is fine for F-Open. Mike McCasland wanted to see the potential of the cartridge for long-range target shooting, so he put a 6mm GT-chambered Bartlein barrel on a nice custom rifle with McMillan XIT stock and Kelbly F-Class Panda action. The results were impressive.
6mm GT — New Cartridge with Multi-Discipline Potential
Story by Mike McCasland, Texas Precision
The 6mm GT began garnering attention within PRS circles in early 2019. It promised to shoot 105-110gr 6mm bullets at 2950-3000 FPS, yet not suffer from mag-feed issues sometimes found with 6mmBR variants such as the 6 Dasher, 6BRX, and 6BRA. Moreover, since it burned less powder, the 6mm GT promised increased barrel life compared to the 6mm Creedmoor or 6XC. The 6mm GT case size should still work with the accurate powders in the Varget burn-range. I found the 6GT also worked great with H4350.
As someone who aspired to building a repeater and jumping into the PRS game, and had a spare F-TR rifle sitting around, I thought it would be fun to build up a 6mm GT to see if there was any merit to the hype. My smith, Wes Ripley of RIP Precision in Texas, builds a lot of PRS rigs, and already had the reamer on hand (a 0.120″ freebore variant).
Whidden Gunworks had some 6mm GT FL bushing die kits in stock, so I figured why not see what all the fuss was about? At the very least I could play around with the 6mm GT in F-Open Class at local club matches to see how it compared to the 6BRA, 6 Dasher, and other popular 6mm cartridges.
How the Project Got Started with Backup F-TR Rig
My 6mm GT build really started as a project spawned purely from COVID-19 Isolation boredom. This rifle primarily serves as a backup F-TR gun, and it had been relegated to performing some load development on .308 barrels, so I could spin new ones on my main match rifle. The only problem was, I had run out of .308 barrels that needed load development. So, I basically had an ideal test platform just collecting dust in the safe. All I needed was a 6mm GT-chambered barrel, since (like the 6mmBR) the 6mm GT works in a short action with a .308 Win-sized bolt-face.
6mm GT Rifle Specifications:
Action: Kelbly Panda F-Class SA RB/RP
Stock: McMillan XIT with RAD 2A
Barrel: 30″ 5R Bartlein 1:7.5″-Twist, HV Contour
Scope: Vortex Golden Eagle 15-60x52mm
Trigger: Jewell Benchrest, about 2 ounces
Bipod: Phoenix Precision
About the 6mm GT Cartridge
BRASS — The first thing you’ll find is cartridge brass choices for the 6mmGT are rather limited currently. At present, the only commercial options are Hornady and Alpha Munitions. For the die-hard Lapua fans, you can technically make 6mm GT brass from 6.5×47 Lapua, however that process is very labor-intensive.
I have used both Hornady and Alpha brass in this rifle and haven’t noticed much difference between the two. I will say that my batch of Alpha brass was slightly softer than Alpha brass I’ve used in other calibers; you could feel a difference when neck turning cases. I’m unsure if that’s a batch issue, or something specific to their 6mm GT brass as a whole. As far as performance, there was little discernable difference. Oddly enough, the Hornady brass seemed to have slightly less case capacity than the Alpha; with most other cartridges it’s the other way around.
POWDERS — The 6mm GT was designed with Hodgdon Varget in mind, and that popular powder works exceedingly well in this platform. That said, the 6mm GT can work with a wide variety of powders, some yielding better performance than Varget.
I’ve tried a multitude of powders during my initial 6mm GT load development: Varget, Shooters World Precision, RL16, VV N140, H4350, and RL-15 to name a few. In my barrel, Hodgdon H4350 seems to deliver the best velocity/accuracy combination. SD and ES also seemed to be the lowest with H4350.
Load Development for the 6mm GT — Many Powders Tested
BULLETS — The most common 0.120″ freebore chamber allows for the majority of high-BC 6mm projectiles found in both F-Class and PRS. I had good luck with the pointed 107gr Sierra Match Kings (SMK), as well as the 110gr Hornady A-Tips in my rifle. For those looking to run the heavier 112-115 grain 6mm offerings, I believe GAP designed a 0.160″ freebore reamer that gets those bullets out of the neck/shoulder junction. Shown below is the 0.120″ freebore JGS reamer print:
SUMMARY — Good Cartridge with Much Potential
Generally speaking, I think the 6mm GT is a good little round. Some may not subscribe to this theory, but I believe some cartridges are inherently easier to tune than others. I’m not sure the 6mm GT is as easy-to-tune as a 6mmBR, 6 Dasher, or 6 BRA, but I don’t think it lags that far behind.
With relatively little trouble, I was able to find loads with both Varget and H4350 that would consistently shoot very well — 0.2 to 0.3 MOA. Moreover, I found the 6GT cartridge lives up to the velocity claims made by G.A. Precision. I was easily able to push the 110gr A-Tips to 2950 FPS, and the 107gr SMKs to low 3000 FPS range without any pressure signs, or unnecessary wear and tear on the brass.
As a fun test, I ran my 6mm GT rifle in a local 1000-yard F-Class match with the 110gr A-Tips, just to see just how well they would perform. Although wind conditions of the day and some E-Target issues prevented my 6mm GT rig from getting the better of the larger 7mm and .30-Cal rifles, the 6mm GT proved itself an accurate little round at distance. Here is a 1000-yard ShotMarker target:
After putting several hundred rounds through my 6mm GT rifle, I anticipate building another 6GT on a repeater action to give PRS a try. I think if you are looking for a dual-purpose rifle that can run tactical matches (with 100% feeding reliability), and can also be used for mid-range, F-Open Class competition, the 6mm GT would be a very good option.
About the author, Mike McCasland:
Mike McCasland is an avid shooter who competes regularly in F-Class matches. Based in Texas, Mike is the creator of the Texas Precision YouTube Channel. There you’ll find many videos covering reloading, gun projects, and marksmanship. Mike has done some notable product reviews including a comparison test of Micrometer Competition Seating Dies. To access Mike’s YouTube Channel, CLICK HERE.
As someone who aspired to building a repeater and jumping into the PRS game, and had a spare F-TR rifle sitting around, I thought it would be fun to build up a 6mm GT to see if there was any merit to the hype. My smith, Wes Ripley of RIP Precision in Texas, builds a lot of PRS rigs, and already had the reamer on hand (a 0.120″ freebore variant).
BRASS — Editor’s Report: Lapua now offers excellent 6mm GT (aka 6GT) Lapua brass, product #4 PH6060C. You can also get very good Alpha Munitions 6mm GT brass and Peterson 6mm GT brass. Hornady produces 6mm GT brass as well, but we recommend Lapua, Alpha, or Peterson over Hornady. Lapua 6mm GT brass is in-stock now at Midsouth for $136.99/100 or Mile-High Shooting for $130.00/100. Alpha 6mm GT brass is available from K&M Precision for $130.00/100, and 500-ct bulk packs of Peterson 6mm GT Brass are available at Grafs.com for $548.14.
SUMMARY — Good Cartridge with Much Potential
