Looks like the GAP clan is releasing another new cartridge. Alpha will be making the brass. The guys at Breach Bang Clear posted a video on their instagram page.
The Dasher alternative.
The Dasher alternative.
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6mm GT
- Thread starter Mormegil87
- Start date
Lower pressure means drastically better barrel life. Looks like a .224 Valkyrie formula used on a 6mm. Sounds promising
I would say the big draw based off the video is Dasher performance without the Dasher issues and prep work. However, it's all for not if Lapua, Alpha, or anyone else for that matter start producing factory Dasher brass.
I think you’re right.
Just for comparison sake. Looks to be a dead split between the dasher and a 6x47 Lapua. Dasher is 1.2” to the 40 degree shoulder, GT is 1.3”, Lapua is 1.4” to a 30 degree shoulder. Neck lengths are almost identical between the GT and 47.
This may explain why Alpha hasn't released dasher brass.. which is unfortunate.
I'm in for a 22 GT...
I'm in for a 22 GT...
Ever since the 6.5 SAUM I'm dubious of the claims they make for their cartridges.
The 6.5 SAUM had some very over-exaggerated claims. They definitely inflated the barrel and brass life. That's an overbored cartridge.
Guess we will see what the 6mm GT is all about. Lots of great 6mm options out there today, not sure what this will do better than the other options out there. That said, it's always great for us consumers to have options.
What issues did you have with the Dasher? Keeping it in tune?
I have no experience with Dasher (6BRA shooter myself), but some people swear by the Dasher, others seem to have a lot of issues with it.
I tend to agree here. I know several top shooters that are running the 6x47 or 6 creed at 2950ish with a DTAC with excellent results. I don’t see the need for a new case to accomplish that.
I do think that a slightly short 6x47 with a 40 degree shoulder has the potential to be a bit more efficient in how much powder is needed and still maintain reasonable pressure levels.
The thing is, if you want 3050fps with a 105 bullet you’ve already got lots of options.
Great! You should tell the benchrest guys about it and maybe it will catch on .
Ya, those claims were obviously bogus. I’m surprised so many bought into it. I feel pretty much the same way about the Valkyrie.
I’m curious about their load data for a 105 at 3050 with little pressure.
Because I have a 24” 6xc and I can get 3050 with rl16 .3 grains below ejector marks, 2980 with h4350 and not far from max. And from what I can tell the 6gt should have about based on the data from this years prb caliber article. Dasher is 41.6 grains capacity, 6x47 is 48.5, xc is 50.2. If the guy is halfway between a dash and a x47 then I would be in the ballpark of 45 grains of capacity. And it’s making or improving upon the larger cases. Which makes me think they couldn’t really be that low pressure. Right? What’s the catch that I’m missing?
Because I have a 24” 6xc and I can get 3050 with rl16 .3 grains below ejector marks, 2980 with h4350 and not far from max. And from what I can tell the 6gt should have about based on the data from this years prb caliber article. Dasher is 41.6 grains capacity, 6x47 is 48.5, xc is 50.2. If the guy is halfway between a dash and a x47 then I would be in the ballpark of 45 grains of capacity. And it’s making or improving upon the larger cases. Which makes me think they couldn’t really be that low pressure. Right? What’s the catch that I’m missing?
Its hard to keep up these days! Good for them I guess,they market their stuff very well.
Starting to feel like the golf industry,company’s launching new shit every 6-12 months.
I shot a dasher last year and am back to the 6.5 creed this year,plenty more bullets around now that everyone has gone to the 6mm’s.
Starting to feel like the golf industry,company’s launching new shit every 6-12 months.
I shot a dasher last year and am back to the 6.5 creed this year,plenty more bullets around now that everyone has gone to the 6mm’s.
I may have to hold off on my 224 Grendel barrel - a 22 GT is exactly what I'm looking for.
88/90/95 gr bullets easily moving around 3000, but less brass prep, and a standard bolt face.
Less powder = less recoil/less throat wear/etc.
we'll see how it all shakes out.
If this new 6GT is like the 6 CM but with lower pressures, a.k.a. longer barrel life, it might be interesting. Very interesting times we live in regarding the firearms industry!
22BR will get the 88 ELDM to 3050 with less than 29grs of Varget. I am going to try H4895 in mine.
I think the 6mm market is pretty much done. Hard to make it more efficient
and magically go faster and burn a lot less powder and shoot .1's
How about the 6 creed with less powder. Wow new round, more barrel life and accurate, plus 3000fps..
I'm going to call it the 6L (less )
and magically go faster and burn a lot less powder and shoot .1's
How about the 6 creed with less powder. Wow new round, more barrel life and accurate, plus 3000fps..
I'm going to call it the 6L (less )
Hopefully Alpha makes Dasher brass if this flops.
Is there a correlation published somewhere between chamber pressure and flame temperature and duration (what actually kills barrels)?
223 Remington is pretty high pressure........
Nah, 223 rem is lower pressure. I think saami max is 55k psi.
Heat is what kills barrels, like you said temp and duration. Where pressure comes into play is in creating that heat. Ignore flame temp of the powder burn itself and just consider compressing something like an inert gas such as helium. If you took a 10 cubic feet of helium at standard atmosphere and compressed it down suddenly to 65k psi it would generate a tremendous amount of heat. That’s why pressure contributes to destroying a barrel, because it is part of the factor that generates heat.
My thoughts on this cartridge when it comes to 6br Lapua brass....
OK, I see what's going on. While what you describe is thermodynamically correct, that isn't what's happening inside a cartridge case when the powder burns.
OK there may be a little bit of compressive heating, but 99.9999999% of the heat generated comes from the chemical reaction of combustion. That's why powder quantity and type (single vs double base, kernel size, etc) is I believe the dominant factor in torching throats.
Then there's the duration of exposure to heat which is affected somewhat (I believe) by the cross sectional area of the case mouth.
To be completely honest, over the years I've noticed that laymen attribute a bunch of things to pressure that simply are not so.
I don't know man, I had a 6 creed barrel chew the throat in 800 rounds. Went with a dasher next go round and have significantly less barrel heat when shooting. I can do a 10 round string and barely have any barrel heat where the 6 creed was HOT! Burning 10 grains less powder to the same bore diameter has to mean something. I digress though, regardless of barrel life comparisons, the dasher is just so damn much fun to shoot! It's like a little pop gun that performs.
That Borden super short 6 action sounds like the real deal. Just talked to John and ordered one. Said it will work just fine in my MPA chassis. Guess we will see
This is the theory behind the 6mm Competition Match that Joe Hendricks developed. I love mine. After more than 1200 rounds this year through my Krieger 6mm Comp Match barrel shooting 105 and 115's using either RL26 or H1000 or (my favorite) Ramshot Magnum my velocities are still the same, no change after the first 200 rounds and the distance to the lands appears to be basically the same as well. To be fair, most of those rounds were HBN coated.
The problem with the 6mm Comp Match is that I'm running between 49 - 50grs of Ramshot Magnum with a 115gr Dtac at 3050fps. This equates to approximately 7.6lbf recoil in my 15lb gun. This is almost double what a 6mm Creed or Dasher would see. This doesn't seem like much, but after a few hundred rounds in a day, it still wears on you. And, with the lower recoiling caliber your recoil management only need to be half as good to have better follow through on your shots.
I love my 6mm Comp Match and I'll continue to shoot it, but I'm actually looking at a 224 Grendel this year......(easier than a 22 Dasher)....but the 22GT may be alright too.
Regards,
Ross
Why do you believe that? Based on what?
I’m all for elevating the discussion above the laymen level to something knowledgeable and factual.
The reason it's rarely used is because it has a longer neck than Dasher brass fireformed from what was originally BR brass. This means it either requires trimming or it needs a different reamer.
Apparently it's decent stuff, and I think the longer neck could be beneficial, but because it doesn't fit the standard dasher reamer chambers it's not popular at all.
Believe what, that pressure has no bearing on throat wear? I don't believe so. I know so. I know so based on my academic and practical knowledge of engineering mechanics, thermodynamics, and metallurgy.
I told you, for all practical purposes there is no gas being compressed in a rifle's chamber. The pressure rise is not caused by an input of mechanical work into a closed system (which is how gasses are compressed). The pressure rise is caused by the generation of a gasseous mass in a closed system (closed until the bullet leaves the barrel) that for a brief moment has a constant volume (until the bullet begins to move).
How is that mass of gasses being created? As a by product of combustion. The other by product of combustion is heat. The exposure of barrel steel just ahead of the case mouth to extremely high temperature plus the physical erosion of the accelerating gasses and solids is what destroys the throat.
There is some gas (air) between the chamber walls and the case which is compressed when the brass expands, but that is hardly what can be called a closed system so any compressive heating generated there is either trivial or non-existent and in any case it never reaches the throat.
You know what else is true? Peak chamber pressure has no relationship to muzzle velocity. The size of the area under the pressure vs time curve is what does.
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You speak with an air of authority and certainty. Setting aside whether this is simply a personality trait let’s entertain the discussion.
Burn 35 grains of loose powder with a match, sitting on the ground. It creates (for the sake of argument) 10 cubic feet of gas. Now set aside whether creating that gas in a confined space is a compressive force, you still have the counterpoint of gas expansion being a cooling force. If there is no compression, are you only left with expansion cooling, where greater total volume/pressure produces greater cooling on expansion? To me that flies in the face of logic.
The much more plain answer is that the gas created on burning is a fixed volume, and to create it in a confined space is to convert that energy into work aka compressive force. The byproduct of that compressive force is both the energy that moves the bullet and unavoidably the heat generated by compression of gasses.
If you observe powder burning in an open environment you can see that it doesn’t burn all that fast, not nearly as fast as a bullet fires. The pressure (and heat) of the confined chamber accelerates the chemical reaction of powder burning so that it happens much faster.
There are a couple observable real world phenomena that tend to support this. One is the “spike” in the rate of the pressure curve you see in some powders as you reach max pressure. The addition of a bit more pressure and heat accelerates the whole power cumbustion so that adding a small amount of powder when near max creates much more result than adding the same amount of powder does at lower pressure. If pressure was not connected to combustion temperature then you should not see this acceleration of chemical reaction (powder burning).
The second observation is how barrel life responds to reducing loads (reduced pressure). While this is a broad observation, if you back off a couple grains from max charge (say 7%) the general report is one of a greater percentage increase than the powder change alone. This is suggestive of a nonlinear process at work.
I have a hard time reconciling that pressure and heat are not interrelated.
Borden uses proprietary mags specifically designed to feed the BR family from what I understand, that and an action the correct size for correct delivery of a normal let off from the feed lips. That's a huge reason for me right there!
It took 3 tries for me to get the mag lips tweaked to feed okay with AICS and PR kit, that was very annoying and I almost changed my mind about staying with 6mmBR because of that hassle.
Borden just about pioneered the bolt timing thing which makes an action feel nicer. Also those Borden bumps.....
I get it!
Your anecdotal observations and confusion between correlation and causality are understandable but tiresome.
In a related matter, someone else tried to teach me what runout means referencing wikipedia and "common knowledge"....LOL
This is kinda the same
Combustion of smokeless powder is an extremely complex phenomenon and unless you're a subject matter expert (and I'm not) I'm not sure why I should give any credibility to what you've said.
At least I'm an engineer and have over a quarter century in the profession. How about you?
Awesome. When you're an idiot with nothing to back up your position, resort to ad hominems.
GAP Needs to reinvent the wheel every few years to keep the retards that have to buy a whole new $5k rifle every time there's a new caliber on the market, salivating.
Nevermind it does nothing ballistically different than current cartridge offerings. I'm sure the barrel life will be 6k rounds too! I'll stick with my 6x47.
And yet you haven’t provided any more data to support your position that Sheldon has... only Sheldon is a valued member of this forum who is always helpful and kind. I’m no Sheldon, I wish I was. He’s smart and you’re basically calling him an idiot in not so many words because he’s not old and full of his qualifications (that’s how your comments read to everyone on the other side of the monitor from you). I don’t say that to take away your contributions, you do have contributed many good things to the forum as well but you also always seem to have a stick up your ass for people who don’t push the fact that they went to school a quarter century ago.
Take note, I don’t disagree with you, and I don’t think Sheldon does either, in fact I agree that it’s pretty much the flame temp and abrasives that wear out a barrel. Here’s a couple papers that support that as well. https://www.nap.edu/read/18418/chapter/7
https://apps.dtic.mil/dtic/tr/fulltext/u2/a440938.pdf
But to say that pressure doesn’t influence those temps and you know that for a fact because you’re an engineer by trade and he doesn’t does seem disingenuous.
You're no engineer if you think pressure and temperature aren't correlated, considering the ideal gas law is really basic stuff taught even to high school students. You wanted data, how about having a fundamental law of nature instead?
PV = nRT
Pressure * Volume = moles of gas * universal gas constant * absolute temperature
When the pressure spikes higher, the temperatures will necessarily also spike higher than the same powder at a lower pressure. How much of an effect this increase has on barrel wear vs the increase from a hotter flame temp is less well studied, however.
You guys are like squirrels chasing a nut.
If you guys want to shoot 3050 with a 105, have exceptional barrel life get a bigger cartridge, stuff a reduced charge weight of cooler burning powder. Keep the long neck and 30 degree shoulder for the perfect funnel and easy feeding.
They're all going to feel about the same, or damn similar. Force= mass x acceleration.
You still have the same mass and your acceleration is going to be similar also.
Don't follow the hype, just sit back and let a few people follow the nut for a bit and see how they shake out of the tree.
The perfect cartridge has already been mentioned in this thread a couple of times. An improved shoulder angle at 30 degrees is the most efficient funnel, this has been proven. Throw a long neck on it so it doesn't torch the throat as bad. Slower cooler powder.
Xdeano
If you guys want to shoot 3050 with a 105, have exceptional barrel life get a bigger cartridge, stuff a reduced charge weight of cooler burning powder. Keep the long neck and 30 degree shoulder for the perfect funnel and easy feeding.
They're all going to feel about the same, or damn similar. Force= mass x acceleration.
You still have the same mass and your acceleration is going to be similar also.
Don't follow the hype, just sit back and let a few people follow the nut for a bit and see how they shake out of the tree.
The perfect cartridge has already been mentioned in this thread a couple of times. An improved shoulder angle at 30 degrees is the most efficient funnel, this has been proven. Throw a long neck on it so it doesn't torch the throat as bad. Slower cooler powder.
Xdeano
