Range Report 6GT Project/Range Report

[ReplicaSnipers]

I've got a reamer and dies, just waiting on Alpha brass to clear Brisbane customs...this has taken more time than it should have but I should have one up and running next year.

Nice. Did you buy the brass directly from the US? How much was it if you don’t mind me asking? Also are you going to hang onto the reamers or wish to sell them afterwards? I’ve got some on order but estimated arrival not for 14-16 weeks!! That’s put a spanner in my works!

 

[KWilson]

Nice. Did you buy the brass directly from the US? How much was it if you don’t mind me asking? Also are you going to hang onto the reamers or wish to sell them afterwards? I’ve got some on order but estimated arrival not for 14-16 weeks!! That’s put a spanner in my works!

3GT have a decent shipment of 6GT and a smaller shipment of 6 Dasher sitting in customs - it's taken so long to get it their import paperwork expired. Brass will be around $350 per hundred...

 

[GoferDog]

I will post a step by step of the 47 Lap brass to 6GT at some stage, but for anyone with any reloading nous at all it is very simple. Not to mention half the price. 47 brass is completely cleaned at 13 thou. Leaves you with a 269 loaded round. I would die losing brass at $3.50 a piece...

 

[GoferDog]

After going through the bushing die and before trimming.

 

[762 ULTRAMAGA]

Man this thread was 18 pages hot the first year then nothing...
I'm really interested in some updates now that Lapua announced GT brass.

Are those of you who've been shooting the GT getting barrel life significantly better than a 6 creed, or comparable to initial claims??

Is there a tangible benefit going with the GT over a BRA shooting 110-115s in longer distance matches here in the west?

 

[Kadams1563]

Best part of GT over BRA is not fire forming Lapua 6BR brass and it will feed better.

The GT is a good round. IMO 6GT if you want a little more speed or STRAIGHT 6BR if not.

 

[Niles Coyote]

I've been using one since late 2019, love the cartridge and I have been getting 3000+ on my barrels. The first barrel went to 3600 round before it had a sudden change in POI and drop in velocity but looking back I think it was starting to show signs at 3200 as I had a few shots drop here and there that were unexplained misses. My other three I have taken off once they hit 2900-3000 range. They are sitting in reserve for training use to finish out their life. That said, I am running the 6GT slower than most, pushing 108's,109's and 110's in the 2830-2850fps range.

I've been considering moving to 6mm BR or BRA now that more reliable mags are available but the cost of brass, dies and having Barrels chambered ready to go have kept me with the GT for now. At the speeds I am running I have not had any issues with brass primer pockets in either Hornady or Alpha.

I'm currently running 32 grains of Varget under a 108 Elite Hunter jumping .060" from Alpha brass on its tenth firing pictured below. This barrel has about 2300 rounds on it when this was recorded and has tended to be a faster than usual barrel, other barrels required a half to full grain more powder to reach this speed. It's a proof barrel and I suspect it has a tighter bore than the Benchmark's and Bartlien's I have used in the past.

 

[762 ULTRAMAGA]

I've been using one since late 2019, love the cartridge and I have been getting 3000+ on my barrels. The first barrel went to 3600 round before it had a sudden change in POI and drop in velocity but looking back I think it was starting to show signs at 3200 as I had a few shots drop here and there that were unexplained misses. My other three I have taken off once they hit 2900-3000 range. They are sitting in reserve for training use to finish out their life. That said, I am running the 6GT slower than most, pushing 108's,109's and 110's in the 2830-2850fps range.

I've been considering moving to 6mm BR or BRA now that more reliable mags are available but the cost of brass, dies and having Barrels chambered ready to go have kept me with the GT for now. At the speeds I am running I have not had any issues with brass primer pockets in either Hornady or Alpha.

I'm currently running 32 grains of Varget under a 108 Elite Hunter jumping .060" from Alpha brass on its tenth firing pictured below. This barrel has about 2300 rounds on it when this was recorded and has tended to be a faster than usual barrel, other barrels required a half to full grain more powder to reach this speed. It's a proof barrel and I suspect it has a tighter bore than the Benchmark's and Bartlien's I have used in the past. View attachment 8325410

That's impressive! Thanks for the input.
You're already getting BR barrel life so why would you even consider changing things up?

 

[Evlshnngns]

Lapua brass will supposedly have less powder capacity, should be even closer to dasher.

 

[Darkside-Six]

Best part of GT over BRA is not fire forming Lapua 6BR brass and it will feed better.

The GT is a good round. IMO 6GT if you want a little more speed or STRAIGHT 6BR if not.

I’ve been shooting it since 2019. Average barrel life has been roughly 3500 rounds +/- a hundred or so. Lapua will be interesting but I switched to the Alpha over the Hornady a few years ago and have been please. Nothing wrong with the Hornady. I had some of the first batches and think I had 10 or so for rings on them. Made it through 2 barrels. The Alpha is a little thicker brass similar to how Lapua is and has been holding up better. I’m not going to run right out and switch to Lapua the minute it drops but may look at grabbing a bunch later on when I swap out my barrel again. As far as the difference with GT over BR is not having to fire form brass and no feeding issues.

 

[762 ULTRAMAGA]

I’ve been shooting it since 2019. Average barrel life has been roughly 3500 rounds +/- a hundred or so. Lapua will be interesting but I switched to the Alpha over the Hornady a few years ago and have been please. Nothing wrong with the Hornady. I had some of the first batches and think I had 10 or so for rings on them. Made it through 2 barrels. The Alpha is a little thicker brass similar to how Lapua is and has been holding up better. I’m not going to run right out and switch to Lapua the minute it drops but may look at grabbing a bunch later on when I swap out my barrel again. As far as the difference with GT over BR is not having to fire form brass and no feeding issues.

That's also fantastic barrel life, are you running lower pressure loads as well? Do you mind sharing your powder bullet combo

 

[Darkside-Six]

That's also fantastic barrel life, are you running lower pressure loads as well? Do you mind sharing your powder bullet combo

Alpha brass, Varget, and Berger 109 hybrids. I like to run them right at 2850.

 

[ghostrider_OneOne]

That's also fantastic barrel life, are you running lower pressure loads as well? Do you mind sharing your powder bullet combo

I've been shooting the GT for a little over three years now. My barrel life has been very similar to what has already been reported; 3000+ on first barrel (lots of different load development done on this one), 3200+ on next two going about 2835 with 105's. I just got a 400ModBB spun up and very curious to see how that does. Sorry don't have enough data to share on that one. I have only shoot Bartlein and Benchmark barrels 26".
I don't have extensive experience with BR or BRA. I will give the GT another plus for working well with several different powders. Here is what has worked for me:

4166 32.4 105's 2815fps, consistent SD around 4, 20 shot string, I used this powder when I couldn't find anything else, worked great, doesn't get talked about much around here

Varget 33.0 105's 2840fps, SD's around 5, 20 shot string

RL16 37.3 112MB 2910fps SD's around 3.5, 20 shot string, This have been a fantastic load. I don't use it as much as I used to for a couple reasons. First I had issues with carbon rings. I solved this by cleaning more often and doing a better cleaning job (time consuming). Next I have two identical rifles both cambered in 6GT. My thinking was one for matches (whatever barrel shoots best) and one for training. Sadly my local range has had issues with 'Fish and Game' who has administrative authority over land use. They shut down our long range portion of range (1000y to 1450y). I won't get in to the issue but typical BS. So we still have a great range but our max distance is now 950y. At 950y I really don't need a 112 going 2910, it's overkill. The 105's more than do all I need. I want both rifles to be set up exactly the same. If I'm shooting two different loads in each rifle it defeats the purpose.

H4350 36.5 112MB 2900fps SD's around 5.

105's I jump .040 and 112's .060
As for brass, early on I used Hornady. Worked great no issues, got 10-12 firings. Now still using alpha OCD 'gay tiger' head stamp. I bought 600 pieces, 400 have 8 firings and 200 have 16 firings. Primer pocket all tight as day I bought brass. I anneal after firing. Not sure how much longer I will go with the 16's but close inspection looks good. Hornady pockets got loose at 10-12, haven't experienced that with alpha.

 

[762 ULTRAMAGA]

I've been shooting the GT for a little over three years now. My barrel life has been very similar to what has already been reported; 3000+ on first barrel (lots of different load development done on this one), 3200+ on next two going about 2835 with 105's. I just got a 400ModBB spun up and very curious to see how that does. Sorry don't have enough data to share on that one. I have only shoot Bartlein and Benchmark barrels 26".
I don't have extensive experience with BR or BRA. I will give the GT another plus for working well with several different powders. Here is what has worked for me:

4166 32.4 105's 2815fps, consistent SD around 4, 20 shot string, I used this powder when I couldn't find anything else, worked great, doesn't get talked about much around here

Varget 33.0 105's 2840fps, SD's around 5, 20 shot string

RL16 37.3 112MB 2910fps SD's around 3.5, 20 shot string, This have been a fantastic load. I don't use it as much as I used to for a couple reasons. First I had issues with carbon rings. I solved this by cleaning more often and doing a better cleaning job (time consuming). Next I have two identical rifles both cambered in 6GT. My thinking was one for matches (whatever barrel shoots best) and one for training. Sadly my local range has had issues with 'Fish and Game' who has administrative authority over land use. They shut down our long range portion of range (1000y to 1450y). I won't get in to the issue but typical BS. So we still have a great range but our max distance is now 950y. At 950y I really don't need a 112 going 2910, it's overkill. The 105's more than do all I need. I want both rifles to be set up exactly the same. If I'm shooting two different loads in each rifle it defeats the purpose.

H4350 36.5 112MB 2900fps SD's around 5.

105's I jump .040 and 112's .060
As for brass, early on I used Hornady. Worked great no issues, got 10-12 firings. Now still using alpha OCD 'gay tiger' head stamp. I bought 600 pieces, 400 have 8 firings and 200 have 16 firings. Primer pocket all tight as day I bought brass. I anneal after firing. Not sure how much longer I will go with the 16's but close inspection looks good. Hornady pockets got loose at 10-12, haven't experienced that with alpha.

Man that's some great input, I appreciate all the details.
I'm not far into my creed so I'm in no hurry, but I'll gather some Lapua brass and have a GT barrel ready to go when she quits on me.

 

[sierracharlie338]

Very solid info here. I’ll be adding a GT to the queue very soon. Just need a barrel.

 

[Hopar]

What is an optimal barrel length and twist for the 6GT?

 

[ReplicaSnipers]

Check out the precision rifle blog’s most recent ‘What the pros use’ article.

 

[Niles Coyote]

What is an optimal barrel length and twist for the 6GT?

I didn't see anything on PRB's barrel article regarding twist rate so I will weigh in. Rifling twist is more dependent on the length of bullet you choose to use and the air temp and air pressure you will be using it in than the caliber choice. If your shooting matches year around in super cold climates near sea level, that is where twist will be most critical. A few years ago, Bryan Litz did a test on bullet stability and at the end of his testing suggested that you want to stay at a SG rate of 1.5 or higher to ensure your BC remained consistent. This isn't to be confused with the bullet becoming unstable in flight and hitting the target sideways. Just if you want your ballistic app to be as predictable as possible stay above a 1.5 rating.

So, the best way to answer this is to look it up using your own data. 4DOF and JBM both have calculators and I think it's in the AB app as well.

To this point the 6mm bullet I have found to require the most twist for stability rating is the 109 ELD from Hornady. If you're wanting to use that bullet a 7.25 will work well down to freezing. If you are going colder, as we did at one of our recent Indiana matches where the day opened at -3 degrees and we were within a couple hundred feet from sea level you would have wanted to have a 7 twist. That said, if you were using a Berger 109 hybrid at the same match and conditions you could get by with a 7.25...

So, after all that, I'll end with a lot of folks are using 7.5 and never had a reason to look elsewhere. I've used both 7.5 and 7... I'll probably do a 7.25 next LOL.