The New 6GT Cartridge for Precision Rifle Competition

Report by Vu Pham
Earlier this year I was ready to build a 6 Dasher when I saw a lot of buzz on the interwebs about a new caliber George Gardner (Owner of GA Precision) and Tom Jacobs (Owner of Vapor Trail Bullets) designed, the 6GT. After some research and talking to George, I ditched the 6mm Dasher build and had GA Precision build me a 6GT on a GAP Templar action I already had in the safe. The reasons to try the 6GT in a new PRS-style rig were as follows:

1. Push a 110-115 grain class bullet at 2880-2930 FPS safely in the Sacramento heat.

2. Achieve a load that is reliable and predictable. The caliber must be easy-to-tune and predictable from barrel to barrel. I don’t want to spend weeks developing a new load each time I spin on a fresh barrel.

3. Be able to run the same mag in all my guns without having to tweak or use mag kits. The round must feed from AICS and AW magazines without major tweaking or hiccups.

4. Get good barrel life. The barrel needs to go 2200-2500 rounds with match-grade reliability and accuracy.

5. Have a competitive cartridge with the least possible recoil without sacrificing too much performance down range, compared to bigger options like the 6mm Creedmoor.

6GT feeding from un-modified magazines has been flawless in all the rifles we tested. The 6GT feeds so well, I sometimes have to do a press check to ensure there is a round in the chamber.

On paper the 6GT seemed like the perfect cartridge for PRS- and NRL-style competition. It has the low recoil of a 6 Dasher, with good feeding and mag compatibility. With the 6GT, a competitor can push 105gr bullets at 3000+ FPS or run heavier bullets at 2800-2900+ FPS.

Knowing that I would initially have to make my own 6GT brass and do quite a bit of load development, I enlisted the help of Dan Bertocchini with CS Tactical. Dan has a lot more experience with wildcats and is the man when it comes to this type of data gathering. He has been running a 6 Dasher for a few years so I was curious how he would compare the 6GT to his 6 Dasher.

Quick Summary: “I am really digging the 6GT and the capabilities it offers. It can launch 103gr Vapor Trails at 3000+ FPS or lob heavy 115gr DTACs in the low-to-mid 2900s comfortably. I think we will see this cartridge go mainstream in PRS/NRL-style competition in 2020.” — Vu Pham

Alpha Munitions Pre-Production 6GT Brass
George Gardner was kind enough to send us 50 pieces of Pre-Production Alpha 6GT brass for preliminary testing. Like the cases I formed from 6.5×47 Lapua brass, the Alpha 6GT brass will use a small rifle primer. Price from Alpha Munitions should be $1.15 per case, which is on par with Alphan’s other product line.

The first 7000 pieces of Alpha 6GT brass sold before I could even get my hands on any! The bigger batch of production brass is due later this year. To pre-order the brass, CLICK HERE.

The major difference between 6.5×47 Lapua-formed brass and Alpha 6GT brass is the case capacity. Alpha 6GT brass has 1.5 to 1.7 grains more case capacity. When a piece of 6.5×47 Lapua brass is formed into a 6GT, the walls of the case now become the shoulder and part of the neck. In a normal piece of brass, the shoulder and neck are typically thinner because of the thickness of the brass tapering from the body to neck.

While the cartridge design was optimized for Hodgdon Varget, the extra case capacity of the Alpha 6GT brass opens the door to Hodgdon H4350 (my favorite powder) and Alliant Reloder 16.

Test Results with Alpha Munitions 6GT Brass
Initial test results were as expected from a premium brass-maker. Dan and I both got excellent Standard Deviations and Extreme Spreads over my MagnetoSpeed V3 and his LabRadar. This string below was with 112gr Barnes Match Burners and 33.8 grains of Varget. Can’t complain about a 3 FPS Extreme Spread!

Yes, H4350 Works with the Alpha Munitions Brass
Personally, I prefer running Alpha 6GT brass with H4350 rather than Varget pushing a heavier bullet. H4350 burns slower and cleaner which should equate to better barrel life. The Lapua-formed 6GT cases just do not have the capacity to reach the cartridge’s full capability with the slower burning powders.

Is the 6GT cartridge accurate? Definitely. Here is a 5-shot group at 600 yards shot by Dan. This was Alpha 6GT brass, with Hodgdon H4350 pushing Barnes 112gr Match Burner bullets.

And here is a 4-shot, 600-yard group with reformed 6.5×47 Lapua brass, using Varget powder under a Barnes 112gr Match Burner.

6GT Stress Test — Don’t Try this at Home!
Dan and I also did a “destruction test” to see how the Alpha 6GT brass would hold up when competitors push the cartridge to its limits. Please note that this is PRE-PRODUCTION brass and Dan and I probably exceeded max load for the majority of the duration of this test. Using Varget powder, we pushed 115gr DTACs at 2950+ FPS on a pretty hot day. We ran the charge weight up until the bolt was hard to lift.

Using this very hot charge, we were able to get 14 firings before the primer pocket failed. That is pretty solid considering that this brass was a pre-production sample that Alpha said did not meet its primer pocket design requirements. With these results, I think a shooter pushing 110-115 grain class bullets in the low 2900s will get 16 to 20 firings from a piece of brass.

Is the GT here to stay?
All signs are pointing to “Yes”. Dies are readily available from Hornady, RCBS, and Redding. Chamber reamers are being produced by PT&G and JGS that can be purchased through GA Precision.

Alpha Munitions is hard at work getting quality brass to the shooters. Quite a few people have already chambered up 6GT barrels before they even have brass in hand. I think we will see this cartridge go mainstream in PRS/NRL-style competition in 2020. With Alpha Munitions production brass almost ready to hit the shelves, I think we will see a lot more data come in from the field by the end of this year.

The Verdict — The 6GT Is Looking Great So Far
I am really digging the 6GT and the capabilities it offers. It can launch 103gr Vapor Trails at 3000+ FPS or lob heavy 115gr DTACs in the low to mid 2900s comfortably. George Gardner has texted me some pictures of very impressive groups pushing an 115gr DTAC at 3000 FPS with Alliant Reloder 16 (a very temp-stable powder with a burn rate close to H4350). That being said, if a guy wanted to push that type of speed and bullet weight, the 6mm Creedmoor is a better solution in my opinion. So far my “go to” 6GT load is a 112gr Barnes Match Burner at 2900 FPS. My other favorite load is a Hornady 108gr ELDM at 2970 FPS.

I think the down-range performance of the 6GT over a 6mmBR and the 6BR variants will be valuable on those days where shooting conditions are not as perfect. Recoil is about the same as the 6BR variants (6BRA, 6 Dasher etc.), but noticeably less than a 6mm Creedmoor. The extra energy down range will make a spotter’s job a bit easier when targets extend beyond 800 yards.

Forming GT Brass from Lapua 6.5×47
Before the new Alpha Munitions brass was available, I tested the cartridge using 6GT made from parent Lapua 6.5×47 Lapua brass necked-down and reformed. George Gardner walked me through the process of forming 6GT brass out of Lapua 6.5x47L. The process is time-consuming and is a huge PITA even with the correct tools. More detailed instructions can be found on my 6GT thread on the AccurateShooter Forum. READ Forum Thread HERE.

Here is a photo of what the brass looks like going through the forming/trimming process.
Left to right: 6.5×47 Lapua brass, sized with the 6GT bushing die with a .266 bushing, chopped/trimmed and turned, and fired-formed.

The formed-from-Lapua 6GT brass performed well and is a good option if one has the time and desire, but I’ll be moving over to factory Alpha Munitions brass once it is readily available.

6GT Tested at 1000 Yards
After seeing what Tom Jacobs is doing with his benchrest gun running Alpha Munitions brass, there is no doubt the 6GT is plenty capable out to 1000 yards and beyond. I have a feeling the Benchrest and F-Open guys are going to dig this new 6mm cartridge as well, at least for 600 yards. Note, in this photo it appears Shot #5 is under a paster, but that might just be a Ballistic-X software input error, meaning that this is actually a 4-shot group. Either way it is still impressive.

This story first ran two years ago, but we’re bringing it back to give you guys a smile this summer. Anyone interested in long range accuracy should enjoy this tale of an amazing 800-yard shot by a talented fellow nick-named “Junebug”…

If you were challenged to hit a quarter (i.e. a 25-cent piece) at 800 yards, how would you respond? Well here’s the story of a man who did take that challenge, and proceeded to put a bullet right through the quarter. Forum member Randy D., aka “Birdog”, provides this entertaining account of how his friend Junebug drilled a quarter at 800 yards one Tennessee evening….

Hitting a Quarter at 800 Yards

Story and photos by Birdog
A friend from Indy visited the DOME last summer and returned home telling stories of eggs at 800 yards. He called me back and said his friends did not believe it and wanted to know if I could hit a quarter out at 800 and mail it to him.

Well, I had finally got the time for that challenge last Sunday. My friend Junebug came over and I told him about a new challenge. Junebug is sort of like Voldoc and does not like to be told it can’t be done and set his sights on the quarter. George Clay had his sleeved 700 6XC with 115gr DTACs and Bug had his Diamondback 6 BRDX and 103gr Vapor Trail bullets.

Junebug and Shayne. The quarter was at back fence row on left of photo, 80 yards short of a half-mile

Early to mid-afternoon is not the time for precision 800-yard shooting as the mirage was terrible and the wind was gusting in the high humidity and 95 temps. We took a few shots and got close but no HIT.

I told Junebug to go home and load some shells and come back at 7:00 and I believed we could make it happen. After 7:00 pm is the best time to shoot as the mirage disappears and the wind goes to zero. We met again at 7:00 and had Shayne Halliburton as witness. I took a few shots then Junebug took a few zeroing shots on metal. He was not satisfied with the grouping so he switched brass.

He had some new Hydro-formed brass that had never been fired. He took three sighters on the metal plate and the first two made two little black spots that were touching. Followed with a third shot that almost touched the first two. Darkness was setting in and I told Bug he better try the quarter now. Through my March scope I could barely see the bright quarter and my 1/16th dot completely covered the quarter.

Junebug moved the Diamondback to the quarter and touched her off. A half second later the bright spot on the black paper was gone. I jumped up and did a dance and war hoop and the Bug jumped up for a high five. Now we hoped we could find the quarter. Luckily it jumped out in front of the backer less than five feet and Bug found it immediately.

Junebug’s Rifle Specifications
Stock: Zebra-painted stock (Shehane ST1000 we believe)
Action: Stiller Diamondback
Scope: March 10-60x52mm with 1/8 MOA clicks
Cartridge: 6mm BRDX (6mmBR Norma 40° Improved similar to Dasher)
Bullet: 103-grain Vapor Trail
Gunsmith: Barrel smithed by Tim Claunch, Memphis, Tennessee

For more information (including history of the Zebra rifle), view this Shooters’ Forum Thread. Credit Boyd Allen for finding this story in our 6mmBR and 6BR Improved Sub-Forum. T-DOME photo by Forum member George.

To demonstrate the talent of the shooters, and the accuracy of their rifles, consider these numbers. During the event, the field of competitors shot a total of 1,128 targets. Amazingly, 210 targets, roughly one-fifth of the total, had 5-shot groups under 2.10 inches. And 62 were less than 1.5 inches. Eleven targets had 5-shot groups measuring under one inch! Yes, sub-inch at 600! The smallest group shot at the Nationals was a tiny 0.624″ by Ben Peters. Donna Matthews shot the best overall target of 0.859″ with a score of 50. Amazingly, Donna’s 0.859″/50 was just one of ninety (90) perfect, 50-point scores.

Astonishing Rifle Precision at 600 Yards
There were sixty-two groups under 1.5″ (i.e. sub-quarter MOA) shot during the IBS 600-yard Nationals. And there were eleven groups under 1 inch. (All groups are five shots.) What’s more, three shooters had 16-target Aggregates under 2 inches (i.e. under 1/3-MOA). That’s stunning — the level of precision in today’s 600-yard game is amazing.

Total Targets Shot – 1128
Sub-2″ Groups Fired – 210
Groups Fired Less than 1.500″ – 62
Sub-1″ Groups Fired – 11
Small Group – 0.624″ (Ben Peters)
Best Single Target – 0.859″/50 Score (Donna Matthews)
Perfect Scores of 50 – 90

These impressive numbers demonstrate how competitive the 600-yard game is these days, and how hard it is to win (even when Mother Nature cooperates).

Ryan Hunt Wins Championship in Tight Battle
When the smoke cleared, Ryan Hunt was the Two-Gun winner, earning the title of 2014 IBS 600-yard National Champion. Congrats to Ryan, who finally won the Championship after finishing near the top three years running. Closely following Ryan were Steve Wilson in second and Darrell Dacus in third. To prove how tough this year’s event was, consider this: Hunt’s 16-target Group Aggregate was a mere 1.8868″, while second place Steve Wilson had a 1.9524″, and third-place Darrell Dacus had a 1.9744″. Those three marksmen all shot stunning, sub-2″, 16-target Aggregates! And the difference between first and third place (with 16 targets shot over two days) was a mere 0.0876″. Think about that….

The top three shooters in Light Gun (LG) overall were Bo Wass, followed by Ryan Hunt and Steve Wilson. LG group winners were Ryan Hunt followed by Spencer Lamm and Johnny Powers. In LG score, Bo Wass was #1, followed by Justin Roberson and past champion Sam Hall. Heavy Gun Group was won by Steve Wilson with Ben Peters and Mike Moses in second and third. (NOTE: Bo Wass shot a standard 6mmBR, not a 6BR improved, showing the parent cartridge is still competitive at 600.)

The top three shooters in Heavy Gun (HG) overall were Darrell Dacus, followed by Steve Wilson and Ryan Hunt. (Note: Darrell shot a straight 6mmBR with Berger 105s, not a Dasher.) HG score was won by Jim Bauer followed by Andy Ferguson and Darrell Dacus. Top Youth shooter was Rory Jacobs (5th Place Heavy Gun Overall). Among the lady shooters, Sally Bauer took top honors, finishing in 7th place in the Two Gun Overall. Donna Matthews also shot well finishing with 5th place in Light Gun score. To see all the standings, with complete match results, visit the IBS Long Range Results webpage.

Equipment: 6mm Dasher and Vapor Trail Bullets Dominate Memphis Match
The 6 Dasher was definitely the dominant cartridge shot this year, with the original 6mmBR a distant second. In the action department BAT was a runaway first with only two other manufacturers being listed. Barrels were a little more evenly distributed. Krieger and Brux had 8 entries each and Bartlein with 3. Nightforce scopes were well represented with 16 out of the Top 20 shooters (Top 10 LG and Top 10 HG). March, Leupold, and Sightron filled out the rest of that list. Lapua made a clean sweep with no other brass manufacturer listed. To our surprise, ALL Top 20 shooters used CCI 450 primers. Varget was the powder of choice with LRM (Long Range Match pull-down), IMR 8208 XBR, and Norma 203B each being mentioned once. Notably, in the bullet category, there was a new “most popular projectile” this year. Vapor Trail bullets were used by 10 out of the Top 20 competitors with Berger coming in second with 7 of the Top 20. Spencer and Fireform bullets each had one Top 20 selection.

Great Conditions in Memphis
We had great weather conditions to shoot this year. Mornings had temps in the mid 50s with minimal wind to start. The mirage showed up later in the morning but didn’t seem to affect the competition. The three full relays enjoyed temperatures in the mid-80s with mostly sunny skies. The afternoons were relatively calm and sunny to finish the shooting day. On both days, shooting finished around 2:00 and the rest of the day’s events were completed by 4:00 to 5:00 pm, leaving plenty of time to get cleaned up to go out for the evening.

Praise for the Match Organizers
We have to give lots of credit to the Range Official Malcom Koleas and the target crews for their flawless and determined execution of Relay changes, along with providing, clear, repetitive directions to the shooters. All competitors could easily see the results of the many hours of hard work that went into making this match run so well. Many thanks to Mike Moses, David Dorris, and the rest of the crew that made this shoot so special.

Thanks again to Memphis Sport Shooting Association and all other range owners for giving us a place to practice the shooting disciplines we enjoy. The MSSA range is open to their membership 7 days a week and can host almost every shooting discipline one can imagine. If you have get a chance, please take the time to visit this facility, a first rate club for sure.

If you have ever shot Spencer bullets you know how good they are. Unfortunately, the era of Spencer-branded bullets is coming to a close. Clay has decided to sell his bullet-making operation. The good news for shooters is that Clay’s bullet-making expertise will be passed on to a new owner/operator, Tom Jacobs, who will employ Clay’s bullet dies and presses to carry on the tradition of Spencer bullets. Clay’s bullet designs will now be produced in Missouri by Vapor Trail Bullets. Here’s the official announcement:

Vapor Trail Bullets is pleased to announce the acquisition of Spencer Bullets. Clay Spencer, long known for his world record-setting, hand-made bullets, has sold his bullet-making equipment and personally trained Vapor Trail Bullets owner Tom Jacobs in the manner and methods to continue this successful tradition. The bullet making operation has been moved to Spickard, Missouri. Vapor Trail Bullets looks to expand the product line while continuing to produce the bullets Clay Spencer is known for. For bullet orders please contact Tom Jacobs at 660-748-8111.

How Custom Bullets Are Made on Hand Presses
If you’ve ever wondered how custom, match-grade bullets are made, here are images of bullets being made in Clay Spencer’s shop. The images show bullet cores being seated and bullets being “pointed up”. These same presses (modified RCBS Rockchuckers), dies, and other tools have been moved to Missouri to be used by Vapor Trail Bullets.