Range Report 6GT Project/Range Report

[NorCal Vu]

As a lot of you have already heard and seen, George Gardner of GA Precision and Tom Jacobs (2x 600yd/1000yd Benchrest Shooter of the Year) have developed a new round called the 6GT.

Some basic info on the 6GT:

Parent case: 6.5x47L
35 degree shoulder for better feeding.
No magazine inserts or modifications required.
Optimal case efficiency @ 34-35.5 grains of varget.
3020-3080 fps with 103-105 grain bullets and approx 3000 fps with 115's.

Alpha will be coming out with commercial brass by August of 2019.

Dies are currently available from Hornady. RCBS and Redding are due by late fall of 2019

Reamers and Head space gauges are available through GA Precision.

I was just about to pull the trigger on a Dasher build but the 6GT popped up. After doing some reading and talking to George I decided to get one spun up to gather real world data vs. the Dasher, 6BRA, 6BR, 6BRX, and 6CMs we have in our club.

My wants:
1. Push a 115gn DTAC @ 2920 to 2930fps safely in the Sacramento heat.
2. Commercial brass (soon) I don't mind forming to get the ball rolling, but don't want to make 1000s of pieces from scratch.
3. No freaking mag kits. I want to run the same mag I do with every other caliber I own. 260rem, 6.5x47L, 308win, ect.
4. Barrel needs to go 2200 to 2500 rounds with match grade reliability and accuracy. Subjective and will vary by individual needs. Luckily I don't shoot very tight.

George said the 6GT will do everything I am looking for so here we are.

Rifle specs:
GAP Templar Action
Bartlein 1:7.7 twist 6mm M40 Contour finished @ 26"
Huber Trigger Single Stage
KMW Sentinel Stock
Vortex Optics 4-27 Razor
APA Lil Bastard Brake

He was also kind enough to send me 20 loaded rounds made from 6.5x47 brass, some Alpha brass to test, dies, Giraud shell holder, and answer a bunch of text concerning forming brass.

I have not done a lot of wildcat type rounds so I enlisted Dan Bertocchini's aka "Dasher Dan" help. He likes to geek out on this stuff and has a lot more experience than I do with this type of thing. Dan also shoots a lot tighter than I do.

 

[NorCal Vu]

The 6GT was formed initially from 6.5x47L. The size of the cartridge is between a Dasher and 6x47L.

Left to Right

Dasher - 6GT - 6x47L

I have not done a lot of "wildcating" so I enlisted Dan Bertocchini's aka "Dasher Dan" help. He likes to geek out on this stuff and has a lot more experience than I do. Dan also shoots a lot tighter groups than I do, so that'll help with range reports.

If you like reloading AND have all the tools, it's actually not bad to do. If you hate to be in the reloading room but have the desire to try the 6GT, wait till Alpha comes out with brass.

Setup did take a bit but the process should go a lot faster now that we are dialed in.

Tools needed:
Hornady 6GT dies.
Giraud Trimmer
Giraud Annealer
Neck turner with 35 degree cutter and 6mm setup. I have the 21st Century power lathe turner which made this process a lot easier and faster. Turning the necks is the longest part of the process.
Mini Chop Saw from Harbor Freight (30.00). No, I am not joking and yes, you need a lil chop saw. Think 300blk out days before brass was readily available.
2 presses is a huge help.

Steps 1-5 will get you 6GT brass that will chamber and shoot, but have a quite a bit of run out and I don't think it's optimum for load dev.

Step 1: FL all your 6.5x47L brass if it has been fired.
Step 2: Run it through the 6GT sizer with a .266 bushing. You will need to run the case up a little at a time. George told me to size the neck, then 100thou each push of the ram, back off each time.
Step 3: Chop the long neck off so you only have to trim a little bit with the Giraud.
Step 4: Trim on Giraud: Length:
Step 4: Turn the necks. You will have a bit of brass to remove as there is a huge donut from pushing all that brass down.
Step 5: Tumble and load.

Note: I would anneal after the first firing for sure.

I took a few extra steps to ensure I had as nice as factory brass as possible for load dev.

Instead of Step 5: Tumble and load, I decided to form the cases using the cream of wheat method of forming. (COW) This is the first time I have ever done this and it actually works pretty well. I was able to form 175 cases in about 1.5 hours without burning up the barrel or components.

Using two old RCBS manual powder drops, I was able to charge cases quickly.

Step 6: Drop 8.0gn of Hodgon Titegroup and fill the case up with COW to the necks. Stuff a piece of tissue in it so the COW and powder stays put. I will also add that use regular small rifle primers as well. No need for CCI 450s for this process.

Step 7: Fire the COW loaded rounds. If you have never done this, it's loud. Sounds like a pistol going off. Ear pro still a must.

Step 8: Tumble and anneal.

Step 8: Resize with 6GT dies.

Step 9: (you can skip this but I am OCD), I threw the cases back on the neck turner to hit any high spots. It took a lil off.

Step 9: Resize and load. At this point you have as perfect a piece of brass that can be. I am hoping to match the quality of factory Alpha brass when it comes out.

The piece of brass on the left is how the case looks after COW fire forming.

Below is a pic of what the brass looks like going through the process.
Left to right: 6.5x47L brass, sized with the 6GT bushing die with a .266 bushing, chopped/trimmed and turned, and fired formed.

Dan on the chop saw:

21st Century Powered Lathe is the cats meow of neck turners!

Ready to load:

First loaded 6GT.

 

[leftyk82]

Pics!

Visible now

 

[NorCal Vu]

First Range Report:
May 11th
Dan took the gun out for initial break in. All rounds were fired at 200yards at Sac Valley Shooting Center.

We were able to load 49 rounds in our first session. I have no idea how we did not end up with 50......

3 rounds were shot @ GAP for pressure testing.
20 rounds of GAP loaded 105 Hybrids were fired.
49 rounds of forming and test loads were fired.

First 10 rounds out of the gun:
GAP Loaded 105 Hybrids. I think Dan said the velocity was 2975fps? He'll jump in here shortly I am sure.

Next 5 of the GAP 105 Hybrid Ammo

Non-Formed Brass
105gn Hybrid
34.5gn of Varget - 3020fps

Non-Formed Brass
105gn Hybrid
33.5gn of Varget

Non-Formed Brass
108 ELDM
33.5gn Varget 2960
Dan called the one at 11oclocked. Noob.

The 115s did not shoot as well. I think we loaded them way too long because they were a PITA to chamber. That being said, 33.5 got 2915FPS on a new barrel.

Dan wanted to try some speed test with H4350 and 115s, so we did.

36.5gn only got 2888FPS.

 

[NorCal Vu]

Round Count Log

3 rounds were shot @ GAP for pressure testing.
20 rounds of GAP loaded 105 Hybrids were fired.
49 rounds of forming and test loads were fired.

Cream of wheat fire formed 175 cases with 8.0gn of Tite Group.

87 rounds 5/27/19 - load dev day.

55 rounds 5/31/19 - Zero rifle, gathered dope from 200 to 1K

Cream of wheat formed 160 more cases.

100 rounds - 6-1-19/6-2-19 NCPPRC LR Matches, 80 to 90 degree weather. COF 2 + 3

120 rounds - 7-21-19 NCPPRC Steel Match weekend. 108s 2960fps 33.5gn of varget 108gn ELDMs

(Cleaned) Zeroed with 15 rounds

8-9 - 25 rounds of load dev
Cream of Wheat FF 201 pieces of brass.

8-16-19 Range/Test Day - 26 rounds

9/20 COW formed 230 pieces of brass

GT 2.0 (1:7 twist)

Broke in the barrel 25 rounds.
Zeroed, practice and shot a LR match: 100 rounds. 112s MB @ 2970fps. 8-3/8-4 2019
8-9-19 Load Dev Day 100 rounds

8/23/19 - 50 rounds @ 600yds


8-16-19 Load Dev and more testing of the 1:7 65 rounds

9-7 & 9-8-2019 - 100 rounds, long range match weekend.

9/20 - 9/22 - Steel Match weekend. 165 rounds

10/4 10/5 10/6 - 175 rounds.

10-13 - 10-14 Bakersfield Match - 220 rounds

Tehama Match - 100rds

Range Day 50rounds 3-6-2020

10-20-19 Deep clean barrel and shot 50 rounds. Fouled barrel in, zeroed (moved scope), and tested a few seating depths. Pushed 112s out 35thou to stay 20 off the lands. 1050rds down the pipe.

11/2 - 11-3 Shot a light practice and Long Range Match. 85 rounds total.
1135 down the pipe and still hamming at distance.

11/17-11/18 - Club Steel Match weekend. 150rds.
1285rds total

11/23 - 11/24 - Tehama Steel Match and practice. 120rds
1405rds

12-6 - 12/7 110rds - NCPPRC SOTY Match
1515 rounds

12/14 Accuracy Test @ 1515 rounds.
Shot 45 rounds of various loads.
1560rds total.

January Range Sessions - Just a few rounds here and there. LR Match was called off due to fog.
60 rounds.
1620rds Total

Feb LR Match and Practice
2/2/2020
80rds
1700rds

3-6-2020
75 rounds Range Day
1775rds.

 

[NorCal Vu]

Notes:

Small flash hole on x47 brass will not work with Hornady 6GT die set, which is made for large flash holes.
Resolution: Ran the decapping pin out long on the x47 die and de-capped the 6GT brass, then sized.

Made a OAL Gauge case:

This is what I got for each bullet measured with Ogive touching the lands:

105gn Berger Hybrid: 1.950"
108gn Hornady ELDM: 1.960"
110gn Hornady ATip: 1.980"
112gn Barnes Match Burner: 1.970"
115gn DTAC: 1.960"

 

[NorCal Vu]

5-27-19 Load Dev Range Report

Cleaned the barrel so I fouled it in with 5 rounds using brand new Alpha brass. These were the first 5 out of the barrel that AM. Moved the zero a touch, fired 3 more.

Checked Zero @ 200yds to foul the barrel in a little. This was with Cream of wheat (COW) formed brass.

Ran these bullets: 105 Berger Hybrids, 108 Hornady ELDM, 110 Hornady ATip, 112 Barnes Match Burner, and 115 DTAC

Data gathered. Looks like I got a solid load for 105s, 108s, 110s, and 112s. Gotta work on that 115s. Dan did most of the shooting while I wrote down numbers and worked the Magnetospeed.

Fired 12 rounds and then let the barrel cool down each time. Will probably load up the 108s and run them out to distance this weekend at our LR match.

Fired 4 rounds of each, except for Target # 15

 

[NorCal Vu]

5-31-19 Shot a NCPPRC LR Practice from 200, 300, 425, 500, 600, 800, 900, and 1000.

Used the COW formed brass (still has a fair amount of run out), but was able to gather pretty solid numbers all the way out.

Used the 108ELDM pushed by 33.5gn of Varget giving me about 2940. Barrel is broke in and sped up.

Conditions were nice. Got into the mid 80s by 11am. Winds were from 11 to 2oclock.

10ring is 4"x3"

Kestrel and everything tracked pretty well. 10ring is 4"x3"

Shot the match on Saturday and Sunday. Saturday went OK, blew some wind calls at distance that cost me. The .270BC life is something I am not use to coming from a 6.5mm 140gn bullet.

Here are some groups from that match. We shoot 3 round per string at various distances.

Dropped 1 out of 12 @ 900. Pretty decent water line considering the mirage and me just not being the worlds best shooter. LOL Brass was COW formed. Should tighten up a lil with full formed brass.

 

[NorCal Vu]

Info Requested/Things to do:

1. Water capacity/Case weight

2. Make a modified case to COAL measurements

 

[D_TROS]

Not bad bro. Interesting for sure. I think you better off with just a 6x47? Meaing - F that brass prep lol...

Pretty sweet package tho. Keep us updated.

Regrds
DT

 

[NorCal Vu]

Not bad bro. Interesting for sure. I think you better off with just a 6x47? Meaing - F that brass prep lol...

Pretty sweet package tho. Keep us updated.

Regrds
DT

With Alpha and possibly other manufacturers coming out with commercial brass, I think the 6GT is worth exploration.

We have Dashers, BRs, BRA, BRX, 6x47s, and every other variant you can think in our club to compare and contrast to.

I have looked at the 6x47. If I wanted to do that, I rather go 6XC or just a 6CM and be done with it.

 

[4RingShooter]

Not bad bro. Interesting for sure. I think you better off with just a 6x47? Meaing - F that brass prep lol...

Pretty sweet package tho. Keep us updated.

Regrds
DT

What up Dorgan!

I agree, if factory brass wasn't in the works it would be a lot of work to fill a case capacity void. I've been running the dasher for a few years now and love it but the fact that no manufacturers have stepped up to make quality dasher brass is disappointing. Running this case with less pressure at dasher speeds would be gtg for me, If you want more speed go with a larger case.

 

[Capt Academy]

I can't wait for your final results! Really interested in this caliber.

 

[GTMANN]

The 6GT was formed initially from 6.5x47L. The size of the cartridge is between a Dasher and 6x47L.

Left to Right

Dasher - 6GT - 6x47L
View attachment 7077918

I have not done a lot of "wildcating" so I enlisted Dan Bertocchini's aka "Dasher Dan" help. He likes to geek out on this stuff and has a lot more experience than I do. Dan also shoots a lot tighter groups than I do, so that'll help with range reports.

If you like reloading AND have all the tools, it's actually not bad to do. If you hate to be in the reloading room but have the desire to try the 6GT, wait till Alpha comes out with brass.

Setup did take a bit but the process should go a lot faster now that we are dialed in.

Tools needed:
Hornady 6GT dies.
Giraud Trimmer
Neck turner with 35 degree cutter and 6mm setup. I have the 21st Century power lathe turner which made this process a lot easier and faster. Turning the necks is the longest part of the process.
Mini Chop Saw from Harbor Freight (30.00). No, I am not joking and yes, you need a lil chop saw. Think 300blk out days before brass was readily available.
2 presses is a huge help.

Below is a pic of what the brass looks like going through the process.
Left to right: 6.5x47L brass, sized with the 6GT bushing die with a .266 bushing, chopped/trimmed and turned, and fired formed.

View attachment 7077920

Dan on the chop saw:
View attachment 7077921

21st Century Powered Lathe is the cats meow of neck turners!

View attachment 7077922

Ready to load:

View attachment 7077923


First loaded 6GT.

View attachment 7077924

Step 1: FL all your 6.5x47L brass if it has been fired.
Step 2: Run it through the 6GT sizer with a .266 bushing. You will need to run the case up a little at a time. George told me to size the neck, then 100thou each push of the ram, back off each time.
Step 3: Chop the long neck off so you only have to trim a little bit with the Giraud.
Step 4: Turn the necks. You will have a bit of brass to remove as there is a huge donut.
Step 5: Tumble and load.

Did you anneal before loading after sizing down? What did you turn the necks too? Thanks!

 

[idahoorion]

Hey Vu, nice write up, Excalibur is pretty happy with the 6 slr but it's worn out so viewing with interest. Carry on!

Idahoorion

 

[Steelhead]

Watching with interest. Thanks for the report!

 

[KWilson]

Thanks for the detailed writeup, keen to look into this cartridge when it becomes available. Question: Is there anything stopping you from forming brass out of either 6XC or 6 creedmoor brass to avoid the small primer hole with the Hornady FLS? And is it necessary for you to neck turn or is it simply a tight neck chamber you had a reamed?

 

[lte82]

Whats the case capacity with lapua brass?

 

[lumberjack78]

Thanks for the detailed writeup, keen to look into this cartridge when it becomes available. Question: Is there anything stopping you from forming brass out of either 6XC or 6 creedmoor brass to avoid the small primer hole with the Hornady FLS? And is it necessary for you to neck turn or is it simply a tight neck chamber you had a reamed?

Hornady has small diameter decap pins if that is a concern.

 

[4RingShooter]

Whats the case capacity with lapua brass?

After one fire forming the lapua brass was around 43.3 grains of h20 capacity. My dasher weighs at to 41.9 for comparison. If Alpha can match that capacity or get close to it we will be gtg. If they don't and it has too much you might as well just run a 6x47.

 

[lte82]

After one fire forming the lapua brass was around 43.3 grains of h20 capacity. My dasher weighs at to 41.9 for comparison. If Alpha can match that capacity or get close to it we will be gtg. If they don't and it has too much you might as well just run a 6x47.

Yea my 6x47s go 3020 @ 35.5 varget with really good accuracy and brass lasts forever. Seems like the GT is going to do about the same with maybe a grain or so less powder then?

 

[LawnMM]

I enjoyed the read, but I can't help myself ?

Subscribing for the barrel life results

 

[bschneiderheinze]

Alpha 6gt

 

[lte82]

Alpha 6gt
View attachment 7082899

Nice!! Want to sell me some? LOL! But I'm serious though.

 

[bschneiderheinze]

I think you’ll have to get in line it’s Tom’s test brass. He has shot some awesome groups with it at 600 and 1000 with a PRS rifle

 

[KWilson]

Alpha 6gt
View attachment 7082899

Do you know if there is a reamer print available or is it currently kept in-house at PTG with Dave Kiff? Keen to try this in Australia but there's a few moving parts involved such as ordering a reamer, brass, dies etc. Do you know if the brass design is finalised in terms of it's overall dimensions?

 

[bschneiderheinze]

I believe GA precision has the reamer specs. As far as the brass yes that is box of 500 pieces I think Alpha is just waiting on time to produce enough for demand suppose to be available this summer/fall.

 

[bschneiderheinze]

I’m not drinking the koolaide I’m going with the 6brx. GT looks like to much recoil for me

 

[47guy]

I’m not drinking the koolaide I’m going with the 6brx. GT looks like to much recoil for me

hard to beat the BRX with a 108g berger .025 off the lands varget and a fed 205M...

 

[bschneiderheinze]

Probably going to be to 103 vapor trails for me from here on out been using 107 smk.

 

[mws2000]

Following

 

[NorCal Vu]

Range report posted.

 

[bodhisafa]

^where is it posted?

 

[4RingShooter]

^where is it posted?

https://www.snipershide.com/shooting/threads/6gt-project-range-report.6943024/post-7732785

 

[Sendero_Man]

Hope that info helped you out Vu

Scott

 

[3rd shooter]

Thanks. Enjoyed the info. Keep us posted as to your progress. I'm very interested although I was expecting much better groups. Thats one thing about those Dasher, they are an Hyper accurate round.

 

[NorCal Vu]

Thanks. Enjoyed the info. Keep us posted as to your progress. I'm very interested although I was expecting much better groups. Thats one thing about those Dasher, they are an Hyper accurate round.

Groups are all relative for me because I am not a group shooter. Dan was on the gun, but he doesn't shoot a left handed KMW stock on a regular basis either.

Taking the GT out to distance tomorrow. See how those 108s fly. I will say that even with COW forming, here is a fair amount of run out still.

Vu

 

[Rutter]

I’d like to here how the 110’s shoot out to distance, if you already have data on that I’d sure appreciate seeing it. Thanks in advance.

 

[NorCal Vu]

I’d like to here how the 110’s shoot out to distance, if you already have data on that I’d sure appreciate seeing it. Thanks in advance.

Rutter, I am going to play a lil more with that load and shoot them in a F-Class 3x600 match. Don't have many of them so trying to use them the best I can to gather data.

Vu

 

[NorCal Vu]

Updated the range report in the first few posts. Shot the LR match this past weekend. Put about 160 rounds down range and am pretty happy with the results so far.

 

[bodhisafa]

Getting a barrel spun up, can’t wait to see what this cartridge can do

 

[Off Duty Ninja]

Any new updates? I just got a 6GT Proof SS M24 barrel from Straight Jacket Armory for my Bighorn Origin. Can't wait until Alpha releases the brass.

 

[bschneiderheinze]

Groups are all relative for me because I am not a group shooter. Dan was on the gun, but he doesn't shoot a left handed KMW stock on a regular basis either.

Taking the GT out to distance tomorrow. See how those 108s fly. I will say that even with COW forming, here is a fair amount of run out still.

Vu

Just a heads up on bullets the new vapor trail 103’s are out and they are pretty awesome and reasonably priced. I only ordered 500 to start with because we have enough 107’s to finish this but will probably order 2000-3000 for next year.

 

[anotherwannabe]

What is “new” about them? I don’t see anything on Tom’s website about an update.

 

[NorCal Vu]

Latest update:

The 1:7.7 is rocking the 108s pretty well. Been busy the last few weeks so have not been able to hit the range.

Jorge Bonilla sent me some 105 and 115 RDFs to try out as well.

I have a 7 twist Bartlein at Rubicon Precision being spun up on a new Impact Action.

Dan is getting his 6GT spun up as well.

 

[KWilson]

Latest update:

The 1:7.7 is rocking the 108s pretty well. Been busy the last few weeks so have not been able to hit the range.

Jorge Bonilla sent me some 105 and 115 RDFs to try out as well.

I have a 7 twist Bartlein at Rubicon Precision being spun up on a new Impact Action.

Dan is getting his 6GT spun up as well.

Keen to hear how you find the new 115s, whether they like a huge jump like the 105s and whether the weight tolerances are more consistent. I've got the 105s working but would like to try the 115s when they become available in Australia. The 6GT project will likely kick off next year once I've shot out a 6XC barrel. Can't get things like brass, reamers and dies until around October here.

 

[spife7980]

In my 6xc the 105 rdfs liked to be jumped .020 and in my dasher the 115s looks like they like .030-.035 of jump from touching via the wheeler method.

I would start testing them at .020

 

[NorCal Vu]

Been busy the last few weeks to get any more testing done, but did shoot todays steel match and had a 2nd GT built up by Rubicon Precision. I wanted a tighter twist than a 1:7.7 for the heavier bullets so George was kind enough to get me a 1:7 to spin up.

The 108s are running solid @ 2960 with 33.5gn of varget in upper 80s - low 90s degrees. Ran the gun hard on props all day without any feeding issues.

Reamer was purchased from GA Precision and is the same spec as the first rifle.

Specs on 2nd GT

Built by Rubicon Precision in Cool, CA
Impact Precision LH Action
XLR Envy Chassis
Vortex Gen II Razor
Bartlein 1:7 twist
APA Lil Bastard Muzzle Brake
Trigger Tech Diamond

New rig has about 20 rounds down it and is also liking the 33.5gn with 108s ELDM. I'll be focusing more on the 110 to 115 class bullets in 2nd GT.

 

[3rd shooter]

Thank you for the update. Please keep them coming. There are several of us very interested in the development of this round and there is still not much info or testing I can find out there. Your project and information you are sharing is very much appreciated.

 

[NorCal Vu]

I'd be interested to see what H4350 would look like in that. I started shooting it in my Dasher bc Varget is a throat torcher. Im at a compressed 35gr with 105's at 2910

Tried H4350 with a 115 for a pressure test and the case capacity is not there, which does not surprise me since the case was designed to run Varget or something real similar.