Range Report 6GT Project/Range Report

[K4ylr]

It was in stock on the Alpha Munitions website a week ago. It probably won't be long before it's back. The reviews of the Alpha brass are night and day better than the Norma, and it has the same short neck as Lapua 6BR fireformed.

I've heard different things too about 6GT performance. Some have said you will get Dasher speeds at lower pressure, which doesn't make much sense to me (I think barrel life is mainly related to speed, and I'm not sure pressure really comes from case fill). Plus lower case fill usually makes for less accuracy. Others are saying the speed will be between Dasher and Creedmoor.

Gotcha, I was genuinely asking. I'm coming from a 6.5creedmoor shooting factory ammo and was planning to jump into the deep end with reloading and a 6mm-based cartridge this coming year.

At the time I was having a hell of a time finding Dasher brass that wasn't the frowned upon Norma and was a little shy about having to go through the brass prep to make Dasher brass...on top of having to get mag kits and anecdotal reports of iffy loading.

I can see for the guys that have been running 6mm catridges for a long time that the GT is more of a side step and just something different than a truly game-changing round.

 

[Txmxracer]

Is anyone running the 108 ELDM? If so how is it shooting? Having a new GT spun up as soon as I shoot my last match of the year on Saturday.

 

[Darkside-Six]

So just got out and ran some more rounds down my GT. 34.5 Varget and 105 Hybrids. This is barely 60 rounds down the pipe and I fully expect the barrel to speed up a bit but had zero pressure signs so far.

 

[kthomas]

This cartridge seems like a very good option for those that want 6 BR parent cartridge type performance, but without the initial setup of mags/mag kits and fireforming. I wouldn't be surprised if this caliber becomes really popular.

However, if someone is already invested in 6 Dasher, 6BRA, 6 BRX, etc - I really don't see enough gain to completely swap over to the 6 GT. If you already run one of these cartridges, the feeding problem is a non-issue if you already have the equipment, and IMO fireforming isn't as big of a hassle as some make it out to be. These are great performing cartridges, and the 6 GT isn't going to turn the world upside down for those shooting 6 BR type cartridges.

I believe most are going to try to hot rod the cartridge to squeek the most amount of performance out of it, and barrel life numbers are going to be lower then the expectations in this thread. Most can't resist the allure of extra ballistic performance that comes with pushing a cartridge hard. I think barrel life numbers will average out between a 6 Dasher and 6 Creedmoor.

 

[BoilerUP]

However, if someone is already invested in 6 Dasher, 6BRA, 6 BRX, etc - I really don't see enough gain to completely swap over to the 6 GT.

This is basically where I'm at; Dasher speeds for 2gr more powder doesn't make a value proposition worthy of changing away from Dasher (assuming one doesn't experience feed issues)...especially since Alpha is making both Dasher and GT brass. I do think most folks will lean into the GT a bit, though, ultimately achieving 6XC/6x47L performance with 110-115 class bullets without the benefit of increased barrel life.

Obviously if 6GT barrel life proves consistently 10-15%+ better at Dasher velocities, or better velocity for same barrel life, that proposition equation changes...along with any potential for quality loaded factory ammo.

I'm glad there's folks out there willing to financially invest in beta testing the new shiny, the more data becomes available the more informed folks can be.

 

[Darkside-Six]

All very good points in here. As I mentioned previously, I had not sit 6mm up until this and had planned on switching for the 2020 season so I had to come into this brand new with dies, brass, barrel, etc. I’ve never been one to chase speed, I chase Accuracy. But the barrel life, if true, was the big seller for me.

 

[kthomas]

All very good points in here. As I mentioned previously, I had not sit 6mm up until this and had planned on switching for the 2020 season so I had to come into this brand new with dies, brass, barrel, etc. I’ve never been one to chase speed, I chase Accuracy. But the barrel life, if true, was the big seller for me.

I think it's a great option for someone in your position. Barrel life will be good if you don't hammer it too hard. For someone getting into 6mm, it's definitely a hard option to overlook.

 

[Tactical Taz]

So, just to be clear, your GS got sticky bolt lift at 3080 or he got sticky bolt lift at some velocity and what he settled on was 3080?

Hard bolt lift at 3080 (on a barrel that still has under 40 rounds). I was just trying to show an example of potential velocities. Of course we have to read between the lines a little here as the barrel may speed up. We would not use a load that is anywhere near hard bolt lift by any means. I hope to show what velocities we have seen so far since there doesn't seem to be much info. I am not sure how that compares to how hard you can push those bullets in a dasher.

Edit to add: are all the reports of people running dasher speeds because that is where they have found the upper end to be, or because that is where a node is and they want to run it there versus at the higher node?

 

[trophyhunter]

Hard bolt lift at 3080 (on a barrel that still has under 40 rounds). I was just trying to show an example of potential velocities. Of course we have to read between the lines a little here as the barrel may speed up. We would not use a load that is anywhere near hard bolt lift by any means. I hope to show what velocities we have seen so far since there doesn't seem to be much info. I am not sure how that compares to how hard you can push those bullets in a dasher.

Edit to add: are all the reports of people running dasher speeds because that is where they have found the upper end to be, or because that is where a node is and they want to run it there versus at the higher node?

I don’t recall dasher as it’s been a few barrels back, but my BRA is at 2960 with 105 hybrids. I’ve filled the mag full of water to test pressure as I don’t have a way to “test” it, works great. I can easy push to 3015fps. I didn’t cause I kinda knew where the bullets like to be. And I wanted my brass to hold up. I usually start my barrels on 10 pieces of brass and use those over and over to ensure sizer, chamber & brass all match up. Well those first 10 are still my test, warm up dummies with well over 25 firings. Primers still hold tight, no split necks and same speeds as my other brass that is on 8th firing.
A buddy with this same reamer, tried to run 115’s with 2000MR. He was pushing 2900-3000 with no pressure issues(see pic).
I know lots are running even slower, for trace, recoil or just to run the slower node. But BRA & Dasher had some gas left in the case.

 

[kthomas]

Some of the smaller BR type cartridges have a tendency to mask pressure signs really well. The BRA is known for this. You may think you are not near pressure until you shoot a match in the rain and all of a sudden start having issues.

Smart move on shooting the BRA at 2960 fps instead of 3015 fps. The marginal ballistics advantage isn't worth the tradeoff of reliability. I recently reduced my speed from 3005 fps to 2974 fps - I didn't show any pressure issues, but also didn't want to find out the hard way at a rainy match. ~3000 fps in a BRA is on the high side.

I'm curious if the GT also masks pressure well. People are getting good speeds on here without seeing any signs of pressure, will be interesting to see if there are issues with 6 GT's in the rain and such.

 

[verdugo60]

So just got out and ran some more rounds down my GT. 34.5 Varget and 105 Hybrids. This is barely 60 rounds down the pipe and I fully expect the barrel to speed up a bit but had zero pressure signs so far.

Nice. So when barrel speeds up you could easily get 3050 avg if not more. How was accuracy?

 

[Darkside-Six]

Nice. So when barrel speeds up you could easily get 3050 avg if not more. How was accuracy?

Pretty good so far. I plan on working up a load with A-Tips after I shoot these last 40 hybrids. Got a box of 105’s to kinda warm up with cause I’ve herd from a few that you need to get the barrel settled a bit before really working up a load. But so far these are looking really good

 

[trophyhunter]

Some of the smaller BR type cartridges have a tendency to mask pressure signs really well. The BRA is known for this. You may think you are not near pressure until you shoot a match in the rain and all of a sudden start having issues.

Smart move on shooting the BRA at 2960 fps instead of 3015 fps. The marginal ballistics advantage isn't worth the tradeoff of reliability. I recently reduced my speed from 3005 fps to 2974 fps - I didn't show any pressure issues, but also didn't want to find out the hard way at a rainy match. ~3000 fps in a BRA is on the high side.

I'm curious if the GT also masks pressure well. People are getting good speeds on here without seeing any signs of pressure, will be interesting to see if there are issues with 6 GT's in the rain and such.

Ya in south texas we never know the weather. I always water test my ammo. Fill a mag with ammo, fill the mag with water, start sending rounds ?. You can tell towards the end of 10rds all dripping wet it’s getting heavier but not stiff. But the AI also mask bolt lift & extraction well. But if I haven’t pierced or blown primers under those conditions, I call it good.
As everyone else I’m anxious to see pressure & barrel life on the GT

 

[B-P-UU]

Is Alpha brass in stock anywhere?

 

[Kadams1563]

I got my GT barrel today. Gunsmith jacked it up and cut it as a 24" instead of 26". So we'll see what the velocity is with 4350. I'm not interested in shooting Varget

so is he replacing it or are you gonna shoot it?

I wouldn’t worry too much about it. Just run 30 FPS or so slower.

 

[Darkside-Six]

I got my GT barrel today. Gunsmith jacked it up and cut it as a 24" instead of 26". So we'll see what the velocity is with 4350. I'm not interested in shooting Varget

Damn that sucks. RL16 is a good powder for it as well.

 

[sleeplz]

Hornady 6mm GT Brass

GAP 6mm GT brass, manufactured by Hornady

www.gaprecision.net

Only hornady left

 

[verdugo60]

I'm going to shoot it. Just the appropriate finishing touch. I guess I can't be too harsh. He sent me a check for the cost of the barrel so it's free. He wanted to make it right.

I guess straight jacket finally came through huh? ( Besides screwing up your barrel length.)

Let us know how it shoots, I'm excited to hear how the H4350 does!

 

[Kadams1563]

Need a reamer.

got to pull the trigger on a GT today for a few rounds. That just made me more excited.

have brass, dies, powder, barrel. Just need reamer and bullets.

 

[verdugo60]

I forgot to control box for the Magneto Speed today but I shot up to 38grs of 4350 without being compressed and no signs of pressure

Any accuracy testing? Also what bullet?

 

[LawnMM]

Hornady?

 

[verdugo60]

@reubenski, thanks for sharing your data. What match? I think Chad at LRI bushed my AI bolt a few years ago, no problems since then, he did good.

This post got me pumped, was already planning to try 105 hybrids with H4350. My brass and dies will be here this weekend, barrel next week hopefully. If I can get out before Christmas I'll post my info with the bushed bolt, I have mostly CCI 400's for SRP's.

 

[LawnMM]

Yep, all Hornady so far. I'm going to compare Alpha and Hornady using the same load tomorrow

I can tell you how that'll turn out now ?

 

[LawnMM]

IMO Hornady brass sucks. It's soft and there's quite a few anecdotal threads to that effect on the Hide.

Seems to do better in bolt guns than auto loaders but I'm personally not a fan.

I'd be shocked if Alpha didn't do better.

 

[Kadams1563]

Keep Hornady at low pressures and you will have no problems is what the consensus seems to be. With that being said I ran Hornady in 6.5 creed until Lapua was released. Hornady had soft primer pockets and the primers were falling out at 3 firings. I guess I was pushing it too hard though so it was my fault it sucked.

I will be loading Alpha in the GT and H4350 gonna go for low node for break in and then ramp it up to 3000FPS with a 108,

 

[LawnMM]

Yeah, it's the consumers fault the brass sucks ?

I've run Lapua hard too, the worst most pressure pounded and violated cases never dropped a primer

 

[Airw4ves]

What bushing size are folks using for Alpha brass and .002 - .003 neck tension?

 

[LawnMM]

Meh, if between the nodes I dunno if it proves anything. I'll reserve judgment till you're done.

 

[Skyking]

I have shot the 6 creed for the last 4 years. Tempest action aw mags. Never had a feeding issue. My 6 creed and barrel where done after the Hornady prs match in june. I have seen way to many guys with feeding issues in the br family for me to want to make the switch. I wont own a gun that loses me points because it doesn't feed or function correctly. For me I made the switch to the GT 100% to have the good things of the br family without the feeding issues. I have 400 rounds down the barrel so far and love it. Berger 109 will be here next week.

I could care less how many rounds I get down the barrel. When it's done will change it. I never found pressure, worked my way up to this load and stopped once the accuracy was there.

Alpha is just up the street from me. They said next GT production run will start at the end of Dec

My load info.
Tempest action
Proof barrel 7.5 twist. 27 inches
Hornady brass
Cci br4
H4350 37
Berger 105 30 off.
3015 SD 1

200 yard groups.

 

[Skyking]

 

[kthomas]

My Dasher's and BRs feed better out of my TL3's than the GT does out of my AI. I keep having to pull the spring and follower out of my AW mag and stretching it. I also get about 1 in 15 that gets the bullet tip hitting the end of the barrel tenon.

Once you get a rifle dialed in to run a 6BR type case from a magazine, it runs like a well oiled sewing machine. Both my Mausingfield 6BRA and my wife's LP Fuzion 6 BRA run incredibly well.

 

[verdugo60]

My Dasher's and BRs feed better out of my TL3's than the GT does out of my AI. I keep having to pull the spring and follower out of my AW mag and stretching it. I also get about 1 in 15 that gets the bullet tip hitting the end of the barrel tenon.

Well that sucks. I just want it to run in my AT! 1/4 moa would be nice too but I would settle on 1/2 if it would run reliably...

 

[47guy]

@Skyking

I’ve shot a BRX for a few years and 3 straight BR barrels and NEVER had feed issues...if someone is having feed issues a little feed lip tuning will fix it...simple.&

as far as your 3 shot 1fps SD...it means nothing...go shoot 50 rounds over the chrony and then talk about your SDs.

I’ve been chasing SDs and ESs for a long time and I’ve NEVER had a 40-50 shot sample under 20-25fps...but I had several 5 shot 0 SD groups and a couple 10shot groups at 1fps and 2fps in a 6.5x47 but over a large sample ALWAYS in the low to high 20s.

 

[LawnMM]

50 rounds over a chronograph is a waste of ammo.

Statistics are great when you're into math, little wasteful in this game. If you're into benchrest, go nuts, targets in tactical matches are more than big enough to overcome the 3fps variation in sample sizes of 10 and 50.

 

[47guy]

50 rounds over a chronograph is a waste of ammo.

Statistics are great when you're into math, little wasteful in this game. If you're into benchrest, go nuts, targets in tactical matches are more than big enough to overcome the 3fps variation in sample sizes of 10 and 50.

We’re not talking 3fps variations and in a few of the matches I shoot 30fps will send you over the top at 850yds and you don’t get another shot but that’s not the point the point is that a 3 shot SD Is not solid data.

as far as wasted ammo well I shoot a few prone matches so what better time to collect data?

 

[LawnMM]

Who did the chamber?

 

[Steelhead]

Anyone have a GAP10 chambered in this round? Or would it even work in a gas gun?

 

[lte82]

Hit the range twice today. Put 175rds on the barrel since getting it Thursday. 38.5gr H4350 is compressed when jumping a Hybrid 25 thou. StaBall starts to compress at around 40.6 - 40.8gr. Got some wonky results on Sunday because I pulled the action out of the MPA chassis Saturday. I torqued the 4 action screws down to 45 lbs and figured that would be enough since they're smaller screws. After shooting strangely large groups Sunday and again this morning, I got smart and broke out the 65 lb torque limiter. Fixed the issue.

Alpha Brass does shoot better with H4350 over Hornady. StaBall shoots surprisingly well, in Hornady brass. Haven't tested seating depth in this barrel yet. I got another tip jam today over the course of 80rds. And I felt two more near jams while chambering.

I've thought about selling this barrel, dies, and brass a couple of times over the last three days. Just not sure if the GT is giving me anything over a Dasher. Doesn't seem to shoot as well so far but that could be a number of things. A person could definitely shoot 105s at 3050 without undue pressure although StaBall seems to shoot better at 2960 - 2970.

Have you tried Varget yet? Pretty much magic in my 47's.

 

[stevenc23]

Serious question: Why are so many using H4350 when G. Gardner states in the video above that other than feeding the main benefit of the 6GT is that it has a perfect powder in Varget as opposed to the 6x47L which is stuck between Varget and H4350?

 

[V-Ref]

Hornady brass. Blem RDFs. Piercing primers. Compressed loads. Action screw torque. Two different powders. Two different primers. No seating depth test. 170 rounds. And it’s supposed to shoot like 32.5 of Varget in a Dasher shooting 105s?

How about try the known Varget loads in Alpha brass with a bushed bolt? What if 34.5-35.0 gr of Varget made the gun shoot. Then experiment with IMRs, RDFs, etc.

The comment about giving up on it, made it sound like your not just tinkering around, and looking to find a stable load.

 

[B-P-UU]

Serious question: Why are so many using H4350 when G. Gardner states in the video above that other than feeding the main benefit of the 6GT is that it has a perfect powder in Varget as opposed to the 6x47L which is stuck between Varget and H4350?

Because Varget at speeds north of 3000 fps is basically going to mirror the 6 Creedmoor in terms of barrel life.. possibly worse since varget eats throats pretty bad. Could be fine at one of the lower nodes.

You can't get enough H4350 in a case to hit pressure, 100% case fill, slower burning, etc... we'll see, I'm starting with H4350 and 109's or 112's

 

[verdugo60]

Not sure about others but probably the same as me: Varget seems to torch throats a bit quicker than H4350 or H1000.

It would be another percieved advantage over Dasher if the slight increase in case capacity allowed H4350 in place of Varget.

 

[verdugo60]

I appreciate the data collecting and sharing @reubenski. I just got my brass, dies and 105's in today. AI barrel might come this week from GAP.

I'll be trying Hornady brass with H4350, Varget, 110 SMK's, 105 Hybrids and 115 DTACS.

You know you're spoiled when half moa average 5 shots groups are just "ok". We live in the Golden age of precision rifle. ????

 

[stevenc23]

How is a case size so specific to a burn rate when Varget and 8208 shoot well from 223 to 308? You look at what the reccomended powders were 20 years ago and what we're using in those cases now. We're obviously trending to slower powders. Like, who was it that first started using H1000 in a 6 Creed and boasting longer barrel life numbers? ?

Just going by what the creator of the 6GT said at the 2:40 mark

 

[stevenc23]

Cool, cool....

Hey @stevenc23 don't you shoot a Dasher?

Yes, shooting mostly Dasher and 6BR (but also 223, 223AI, 308, 6x47L, 6.5 Creed and 6.5PRC ), but you know I like the latest greatest shiniest toys out there. So when the Dasher barrel is toast will be considering the GT.

Also not sure I came across clearly. What I was meant to say was that after watching the interview with George and his comments on the 6GT and Varget I was surprised to see so many people going with H4350 in place of Varget. I certainly understand that there are many choices of powder for any cartridge.

 

[trophyhunter]

How is everyone stating that Varget is a throat burner and H4350 is easier on throats but on a big majority of the calibers that run either almost prove completely opposite?

6.5creed,6creed,243 all use H4350 and torch a barrel real fast
BR, BRA,Dasher,223,308,BRX all use Varget and some would say last longer then H4350 & creeds

i can’t see an extra 2-3grs of Varget are going to kill a barrel at 6creed speeds when creeds use 10gr more

 

[K4ylr]

@reubenski in your opinion, if I'm diving straight into the GT as my first 6mm and not looking to drag race the cartridge is it still viable? I'm looking at it for the potential to get near-3000 FPS shooting 105s or 109s while potentially loading with StaBall on a progressive using the RCBS dies to make accurate enough loads. If not, I'd be using R-16 and funneling/dropping that.

I have no experience shooting Dashers or the the BR siblings so the minute differences and/or similarities with the the other 6mm's is't something I'm familiar with or would be comparing to based on my own experiences. Obviously for the guys with barrels coming out the ass and thousands of rounds of other 6mm's all doing slightly different things it's a little less of a cut and dry choice; as you've noticed.

 

[Darkside-Six]

How is everyone stating that Varget is a throat burner and H4350 is easier on throats but on a big majority of the calibers that run either almost prove completely opposite?

6.5creed,6creed,243 all use H4350 and torch a barrel real fast
BR, BRA,Dasher,223,308,BRX all use Varget and some would say last longer then H4350 & creeds

i can’t see an extra 2-3grs of Varget are going to kill a barrel at 6creed speeds when creeds use 10gr more

Exactly. I’ve been following a couple of top shooters who have been shooting the GT for a while now and have well over 2K rounds down the barrel pushing A-Tips at 3010 with Varget.

Just shoot why works.

 

[phlegethon]

Because it's all about burn rate relative to case size. You're right, 4350 is a throat torcher in 6 Creed. In fact, 4350 is to 6 Creed that Varget is to Dasher. You get top velocity in a Creed with 4350. That's why people, myself included, are using RL23, 4831SC, RL26, H1000. All powders of a burn rate that won't push top velocity because you can't get top chamber pressure in that size of a case. Hence, easier on throats. This goes back to the long life theory in the 6.5 SAUM 4S and why people were using H1000 in the Creed. There's context that is implied when people say Varget is a throat torcher...in a Dasher and x47.

I think it’s been shown that velocity of the bullet is the largest factor in throat erosion. And I’ve never heard of H1000 in 6 Creedmoor before you mentioned it here. When I searched for discussion, all I found was a few threads where people said they tried it and it didn’t work well for them.

edit: note also this from https://precisionrifleblog.com/2019/09/06/6mm-6-5-creedmoor-load-data/
Mostly H4350. No H1000.

 

[verdugo60]

I'm not balls deep in competition or 6mm intracisies but reubenski is correct in that H1000 and H4350 are generally easier on throats vs Varget. Varget is a great, useful powder and in traditional 223 heavy loads and 308 barrel life isn't noticed as much because they last 5-8k.

Look up the 6SLR, etc. It was the "cure"
using H1000, to the 243's and 6 Creedmoors that were torching barrels in 1K rounds or less with Varget.

If I can get 2K rounds of legit velocity and accuracy from a GT with Varget or H4350 I'll be super happy. If it feeds reliably in my regular AI AT I'll be stoked too. If it performs more like a 6creed I'll do a Creed next or maybe a 6x47l.