6 MM GT

[cuirc]

I am going to have a 6 mm GT built in the near future I guess a couple of months plus the gunsmith's lead time. Preparing for that "birth" if you will the baby will need feeding. I am at a loss for reloading information and if possible pictures of the grouping. Also having made that decision, I would like to find and information on the cartridge to add to what I already know. Any one please if you have your favorite load(s) and are willing to share I would appreciate it. If you have any articles or write ups on the cartridge I would appreciate getting anything you have to share.
I am just getting into the Precision Rifle discipline. It is really as much an engineering interest as it is a shooting challenge. Love to hear from anyone out there.

 

[kcsmith]

6gt

There’s a couple threads going on that pop back up from time to time. Now that the cartridge is pretty well understood and all the non load questions are asked, time to make sticky for loads and such. My current: 109 berger 0.020 off Cci 450 34.0 Varget Hornady Brass 2950 fps

www.snipershide.com

 

[Rio Precision Gunworks]

Load 33.0 gr of varget and a 109 berger .030 of lands. Spend all the time you can shooting off a barricade at 100yds.

That's just about all there is to know about getting started with 6gt in PRS.

 

[davere]

There's a metric shit ton of data here, Hornady publishes data for the cartridge, etc. It's not hard to find... I mean, basically, a psuedo-random charge of Varget or H4350 with any typical 6mm competition bullet, seated at a random jump... pretty much works, almost as well as BR/BRA/Dasher

 

[ECK]

Here’s what I did when I got my 6GT:

Bought 200 rnds of Hornady factory ammo (109 gr ELD-M) to break the barrel in and get some brass for reloads. The factory 109’s shot pretty well from the get go, so I bought some 109 ELD-M projectiles from GA Precision and tried to replicate the factory load, but with H4350 since I had a lot of it. I ladder tested them, and found several speed nodes in the 2800’s and one in the low 2900’s (which was where the factory load was). But then I read that a lot of guys were settling on low-mid 2800 fps, so I went with one of those nodes and played around with seating depth until I was getting groups in the .3XX’s (FWIW, I suck at shooting groups so was giddy as all get out when pretty much all my test loads were <.7XX” and majority were <.5XX”).

I also tested 108 ELD-Ms when I ran out of the 109’s and they also shot really well. Finally settled on the 115 DTACs and bought enough of those to shoot out my barrel.

Basically what I found was pretty much all the bullets I tested shot really well out to 1K w/ H4350. Or at least good enough for the matches I was shooting.

 

[Badjujuu]

Damn good info!

 

[cuirc]

Load 33.0 gr of varget and a 109 berger .030 of lands. Spend all the time you can shooting off a barricade at 100yds.

That's just about all there is to know about getting started with 6gt in PRS.

Thank you

 

[Niles Coyote]

You will find good loads with Varget, RL-15.5, N150 in the 32-34 range with 103-110 grain bullet weights, SW Precision tends to need a few tenths of a grain less than Varget and H4350 tends to need around 2 grains more to reach the same velocity. I pretty much stay in the 32-32.5 range with Varget and depending on the barrel this usually puts me between 2810-2860fps with 110 A-tips, 109 ELD's, 109 Hybids and 108 Elite hunters.

A few years ago Precision Rifle Blog published work Mark Gordon of SAC was doing and there have been a few podcast's with Scott Satterlee on the same subject as well, regarding bullet seating depth. Their findings suggested that jumping your bullet .055" or more led to more consistent results for the life of the barrel without the need to tune seating depth every few hundred rounds verses seating closer to the lands. I have adopted this approach with my last 3-4 barrels have shared that same experience for the most part. While I can't say I never needed to change seating depth, I did find that it seemed to hold true for 1-2 thousand rounds. I usually exhausted my supply of a given bullet type before the barrel quit shooting. Before adopting this approach, I'd seat to .015-.025" and notice changes in POI as well as groups opening up as the throat geometry changed leading load tuning.

When I started with the 6gt in 2019, Hornady was the only one making brass for a few months and it shot well. I picked up some Alpha brass two years ago and it shot consistently tighter. Lapua advised they will start production at this years Shot show, but I have not heard a release date on it yet.

 

[Cascade Hemi]

Load 33.0 gr of varget and a 109 berger .030 of lands. Spend all the time you can shooting off a barricade at 100yds.

That's just about all there is to know about getting started with 6gt in PRS.

Pretty much this. 36.5gr of H4350 also.

 

[cuirc]

You will find good loads with Varget, RL-15.5, N150 in the 32-34 range with 103-110 grain bullet weights, SW Precision tends to need a few tenths of a grain less than Varget and H4350 tends to need around 2 grains more to reach the same velocity. I pretty much stay in the 32-32.5 range with Varget and depending on the barrel this usually puts me between 2810-2860fps with 110 A-tips, 109 ELD's, 109 Hybids and 108 Elite hunters.

A few years ago Precision Rifle Blog published work Mark Gordon of SAC was doing and there have been a few podcast's with Scott Satterlee on the same subject as well, regarding bullet seating depth. Their findings suggested that jumping your bullet .055" or more led to more consistent results for the life of the barrel without the need to tune seating depth every few hundred rounds verses seating closer to the lands. I have adopted this approach with my last 3-4 barrels have shared that same experience for the most part. While I can't say I never needed to change seating depth, I did find that it seemed to hold true for 1-2 thousand rounds. I usually exhausted my supply of a given bullet type before the barrel quit shooting. Before adopting this approach, I'd seat to .015-.025" and notice changes in POI as well as groups opening up as the throat geometry changed leading load tuning.

When I started with the 6gt in 2019, Hornady was the only one making brass for a few months and it shot well. I picked up some Alpha brass two years ago and it shot consistently tighter. Lapua advised they will start production at this years Shot show, but I have not heard a release date on it yet.

Thank You this is a great help.
I am currently loading for 338 Lapua as a precision rifle (Savage elite). I am getting groups of 3 with a longest distance between the holes of about .625 at 100 yards. I am new to this discipline so I hope to do better but how much?
I have also started loading with the same attention to detail for the 308 in an M-24 which I just acquired and as above I am shopping for a 6mmGT.
For the .338 and .308 above, mindful of throat erosion, from boat tail bullets, for some of my practice loads, I am using a flat base bullet to see how it groups compared to the the boat tail. It would be nice to practice with the flat base if I could cut down on barrel ware.

This is the latest from Lapua's web site on the 6 MM GT:
"New for the autumn of 2024, Lapua will offer a superior choice for competitive shooters with Lapua 6mm GT cartridge cases. Experience unparalleled consistency, quality, and durability with Lapua’s 6mm GT as you pursue excellence in the world of practical precision rifle sports.
The incredible growth witnessed in PRS, NRL, and similar competitive shooting disciplines the past 10 years has heralded the development of high performance, short-action cartridges like the 6mm GT. The GT provides flawless feeding from bolt-action, magazine feed platforms when utilizing the latest high ballistic coefficient 6mm projectiles. Its ultra-efficient cartridge provides low recoil impulse for easy target acquisition and offers excellent precision and velocity consistency. The Lapua 6mm GT difference: We provide superior cartridge geometry that is based on the original 6.5×47 Lapua parent case. This maximizes longevity and optimizes case capacity for the competitive shooter."
It is also interesting to note that Brownells lists it in their catalog as "out of stock notify me" so I would take that as progress.

 

[Csafisher]

Get alpha brass and varget. 105 bergers with 32-33grs.

 

[4O6shootist]

The gt shoots like any small 6mm, easy to tune and accurate. Take advantage of the case capacity and chamber it was a long freebore reamer, and run the cheapest highest bc 6mm there is, the 115 dtac. Call Dtubb and tell him you want 2500 of the same lot number. Load 35, 35.3, 35.6 35.9 H4350 seated 30k jump, or 60k jump for 5 shot samples. Pick the smallest group, verify with a few 5 shot groups on paper at 500y, and you're done. 2820-2870fps has all shot well in multiple barrels for me depending on the length. My 28" I run 35.3gr at 2860. The 26" was 35.5 at 2840.

Screw chasing high priced Berger and atip bullets, or pretty much any the not often in stock match stuff. Dtacs been on the shelf every day now for about a year.

 

[ShootnFool8]

I use 34.1 gr of Varget
2970 fps