6mm GT

[Sheldon N]

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?

If I understand correctly the crux of your argument is “l’m smart therefore you are wrong”.

Two statements come to mind for me... the first being an old proverb, “Let another man’s lips praise you and not your own”. Second is the truism that the highest level of knowledge is demonstrated when one can explain things to others. These are both things that could be quite beneficial to this forum if taken to heart, and will make many more friends than a caustic tone and confrontational posts.

To close the loop on the pressure vs temp discussion I’ll propose a small thought experiment. Imagine a gunpowder which produced no heat, ie. cold burning. Take a charge of this powder and set it off in a small sealed chamber, then after the combustion is complete you can open a valve and release the pressure.

When you release the pressure there must be a cooling effect caused by expansion of gas, this this is basic thermodynamics (like a bottle of propane getting cold when you use your camp stove). The question we are seeking to answer is when you set off the gunpowder (which in our thought experiment makes no heat itself) did it produce heat from compression?

If you say “No” then the experiment just produced cooling energy which did not previously exist. The work energy of the gas was not lost, so where did the cooling energy come from?

It is only possible for equilibrium to exist if the act of compression (setting off the gunpowder in a confined space) also produced heat, in equal proportion to the cooling effect seen when you open the valve. Only one answer makes sense and conforms to the basic laws of thermodynamics.


Circling back to the 6mm GT what does this mean? IMO it means there’s no free lunch and no magic cartridges. Pressure/heat/duration are still going to kill barrels. Sure a longer neck helps a bit to keep the flame in the chamber and a shorter fatter case burns powder more efficiently than a straight walled case but this is so similar to all the other 6mm cases I doubt you’ll see any difference. It’s simply another rung on the case size ladder to choose from. Who knows, maybe it will be Goldilocks for someone out there.

 

[308pirate]

If I understand correctly the crux of your argument is “l’m smart therefore you are wrong”.

Two statements come to mind for me... the first being an old proverb, “Let another man’s lips praise you and not your own”. Second is the truism that the highest level of knowledge is demonstrated when one can explain things to others. These are both things that could be quite beneficial to this forum if taken to heart, and will make many more friends than a caustic tone and confrontational posts.

To close the loop on the pressure vs temp discussion I’ll propose a small thought experiment. Imagine a gunpowder which produced no heat, ie. cold burning. Take a charge of this powder and set it off in a small sealed chamber, then after the combustion is complete you can open a valve and release the pressure.

When you release the pressure there must be a cooling effect caused by expansion of gas, this this is basic thermodynamics (like a bottle of propane getting cold when you use your camp stove). The question we are seeking to answer is when you set off the gunpowder (which in our thought experiment makes no heat itself) did it produce heat from compression?

If you say “No” then the experiment just produced cooling energy which did not previously exist. The work energy of the gas was not lost, so where did the cooling energy come from?

It is only possible for equilibrium to exist if the act of compression (setting off the gunpowder in a confined space) also produced heat, in equal proportion to the cooling effect seen when you open the valve. Only one answer makes sense and conforms to the basic laws of thermodynamics.


Circling back to the 6mm GT what does this mean? IMO it means there’s no free lunch and no magic cartridges. Pressure/heat/duration are still going to kill barrels. Sure a longer neck helps a bit to keep the flame in the chamber and a shorter fatter case burns powder more efficiently than a straight walled case but this is so similar to all the other 6mm cases I doubt you’ll see any difference. It’s simply another rung on the case size ladder to choose from. Who knows, maybe it will be Goldilocks for someone out there.

You're all over the place cherry picking the parts of physics and thermo that bolster your semi intellectual argument. I'm done with this .

I may or may not be smarter than you. That's a question of who's more intelligent and has no bearing on this.

I'm sure there are fields i which you are more knowledgeable than I. Of that I have no doubt. Thermodynamics and engineering mechanics aren't it, of that I assure you.

 

[FatBoy]

norma makes dasher brass, has anyone tried it?

It's excellent brass. The long next is actually been great. It's true that you should get a matched reamer, but that's true of all chamberings.

 

[steve123]

If the mags match the action it makes sense. As long as the mags work. Inventing a mag has been the Achilles heel of many a manufacturer.

I would imagine it would feel similar to running a Howa Mini action with a much lighter lift. Maybe I didn't give it enough practice but I was constantly over running it against it's stops and limits. I figured it would be faster, you know, because it's shorter. But it just didn't work out that way.

I have a Borden Timberline. It's definitely not my smoothest action.

We all hope the Super 6 is well sorted in feeding with the new mags and ejecting well?!! I'm really unlucky on ejection with my Mausingfield and my Surgeon XL - with shorter cartridges, like 6mmBR and 6.5 Saum in them.

The only shorter action I have is a CZ 527, I love the length of the bolt, it feels right to me. This feel is certainly a personal thing so... I haven't handled the SS6 so I comment further.

If I had my idea of a perfect action coming to reality it'd be a scaled down Fortner action made specifically for the 6mmBR family! But the SS6 is getting closer.

Thank goodness for prefits! Between the cheaper price and longer barrel life of 6mmBR I'm not so concerned with barrel life anymore. Next project will be finding a reduced load with I4895, only because I found 10 lbs for $130.

I never did try loading down 6x47L with cool burning powders, maybe someday.

6GAP, it'll be fun to watch what happens with it!

 

[Triggerf16]

Dave Tooley has chambered a 6x44 for several years now. Sounds similar. I have no experience with it. But Dave is a smart guy.

 

[SharpsNitro]

For you guys debating science there is a lot of literature out there on developing and testing solid propellants for guns. I’ve never professionally worked with solid propellants, just liquids and gasses.

A quick search found this article that might help the discussion although it is geared towards the larger guns.

https://pdfs.semanticscholar.org/f39d/588cb0aaee8825634d3bc5a8c1c33bd642d1.pdf

Edit: Here is another paper on erosion in artillery barrels. It has some relevant information. The primary problem is getting the data needed for the commercial powders (i.e. adiabatic flame temperatures, burn rates, heat release, etc.)

https://www.arl.army.mil/arlreports/1999/ARL-TR-1954.pdf

 

[ThePretzel]

I'm sure there are fields i which you are more knowledgeable than I. Of that I have no doubt. Thermodynamics and engineering mechanics aren't it, of that I assure you.

Considering the fact that you're not the only engineer involved in the discussion and that you completely discount the ideal gas law, I'm going to go ahead and "assure you" that what you're thinking may not be as true as you think.

A pressure spike of 60,000 PSI (max SAAMI average pressure) will cause a fair amount of heat. How much heat?

Case capacity of a 6.5 Creedmoor is approximately 52.5 grains of water, or 3.4 grams meaning the volume is approximately 3.4 milliliters. Approximately 50% of this volume will be taken up by solids (the gunpowder and the bullet, taking into account packing density of gunpowders is less than 100%) meaning we get a gaseous volume of ~1.7 milliliters.

Initial Condition:
101,325 * 0.0017 = n * R * 273.15
n = (101,325 * 0.0034)/(R * 273.15)

Solving for n we get that the original amount of gas in the chamber is approximately 0.07585 moles.

Gunpowder is approximately 75% Potassium Nitrate (KNO3), 15% Charcoal (C), and 10% Sulfur (S). The approximate chemical formula for the burning of gunpowder is as follows:

10 KNO3 + 8 C + 3 S -> 2 K2CO3 + 3 K2SO4 + 6 CO2 + 5 N2, of which Carbon Dioxide and Nitrogen are gasses while Potassium Carbonate and Potassium Sulfate are solids. By a percentage of the weight of the original gunpowder, perfect combustion will create 21.96% CO2, 11.65% N2, and 66.39% solids.

Let's use a standard 6.5 Creedmoor load of 40 grains of powder, which with perfect combustion would create approximately 8.784 grains of Carbon Dioxide and 4.66 grains of Nitrogen gas. This translates to 0.5692 grams of CO2 and 0.302 grams of N2, or 0.0129 moles and 0.0108 moles of the two gasses respectively combining for a total of .0237 moles of gas created by perfect combustion of 40 grains of gunpowder.

This means that the new amount of gas in the chamber after combustion (during the pressure spike) is 0.09955 moles. We also have a new volume since the gunpowder isn't there anymore, meaning the volume is approximately the 3.4 milliliter case capacity. The pressure of 60,000 PSI translates to approximately 413,685,420 pascal.

Post Combustion Condition (60,000 PSI):
413,685,420 * .0034 = 0.09955 * 8.3145 * T
T = (413,685,420 * 0.0034)/(0.09955 * 8.3145)

Our final temperature after the combustion, ignoring the heat from combustion itself, is approximately 1,700,000 degrees Kelvin (1.69931 x 10^6). This translates to 3,059,540 degrees Fahrenheit.

The temperatures realistically experienced in the chamber will be a significant amount lower because combustion is not perfect, nor is it instantaneous, and the volume is constantly expanding - this is an idealized spherical cow in a vacuum type calculation. This is demonstrated by the graphs posted already above.

Do you honestly believe though, in the face of the hard math and the data provided, that there is still no correlation between the temperatures and the pressures experienced within the chamber and throat of the barrel?

 

[Yoteski]

Considering the fact that you're not the only engineer involved in the discussion and that you completely discount the ideal gas law, I'm going to go ahead and "assure you" that what you're thinking may not be as true as you think.

A pressure spike of 60,000 PSI (max SAAMI average pressure) will cause a fair amount of heat. How much heat?

Case capacity of a 6.5 Creedmoor is approximately 52.5 grains of water, or 3.4 grams meaning the volume is approximately 3.4 milliliters. Approximately 50% of this volume will be taken up by solids (the gunpowder and the bullet, taking into account packing density of gunpowders is less than 100%) meaning we get a gaseous volume of ~1.7 milliliters.

Initial Condition:
101,325 * 0.0017 = n * R * 273.15
n = (101,325 * 0.0034)/(R * 273.15)

Solving for n we get that the original amount of gas in the chamber is approximately 0.07585 moles.

Gunpowder is approximately 75% Potassium Nitrate (KNO3), 15% Charcoal (C), and 10% Sulfur (S). The approximate chemical formula for the burning of gunpowder is as follows:

10 KNO3 + 8 C + 3 S -> 2 K2CO3 + 3 K2SO4 + 6 CO2 + 5 N2, of which Carbon Dioxide and Nitrogen are gasses while Potassium Carbonate and Potassium Sulfate are solids. By a percentage of the weight of the original gunpowder, perfect combustion will create 21.96% CO2, 11.65% N2, and 66.39% solids.

Let's use a standard 6.5 Creedmoor load of 40 grains of powder, which with perfect combustion would create approximately 8.784 grains of Carbon Dioxide and 4.66 grains of Nitrogen gas. This translates to 0.5692 grams of CO2 and 0.302 grams of N2, or 0.0129 moles and 0.0108 moles of the two gasses respectively combining for a total of .0237 moles of gas created by perfect combustion of 40 grains of gunpowder.

This means that the new amount of gas in the chamber after combustion (during the pressure spike) is 0.09955 moles. We also have a new volume since the gunpowder isn't there anymore, meaning the volume is approximately the 3.4 milliliter case capacity. The pressure of 60,000 PSI translates to approximately 413,685,420 pascal.

Post Combustion Condition (60,000 PSI):
413,685,420 * .0034 = 0.09955 * 8.3145 * T
T = (413,685,420 * 0.0034)/(0.09955 * 8.3145)

Our final temperature after the combustion, ignoring the heat from combustion itself, is approximately 1,700,000 degrees Kelvin (1.69931 x 10^6). This translates to 3,059,540 degrees Fahrenheit.

The temperatures realistically experienced in the chamber will be a significant amount lower because combustion is not perfect, nor is it instantaneous, and the volume is constantly expanding - this is an idealized spherical cow in a vacuum type calculation. This is demonstrated by the graphs posted already above.

Do you honestly believe though, in the face of the hard math and the data provided, that there is still no correlation between the temperatures and the pressures experienced within the chamber and throat of the barrel?

 

[jinxx4ever]

It's excellent brass. The long next is actually been great. It's true that you should get a matched reamer, but that's true of all chamberings.

thank you, that;s what i was wanting to know, I'm having a barrel threaded and chambered , i'll have it chambered to fit

 

[FatBoy]

thank you, that;s what i was wanting to know, I'm having a barrel threaded and chambered , i'll have it chambered to fit

Trying not to derail the thread, but the PTG reamers are out there and new they're only $175. A neck reamer is even cheaper if you didnt want a reamer and wanted an extra .001" neck clearance, etc. After shooting Norma dasher bit out of box and skimmed .0015" I see no difference in performance or pressure.

My 2nd one we throated out about .040" so I can load out longer. The standard reamer seats at the exact same seating depth as the standard 6BR Norma Match reamer, which wastes some of the neck on the Norma Dasher. I suspect I'll be able to get a little more MV as I can compress a slower powder, but no rounds down that pipe yet.

 

[Mormegil87]

After watching a few more videos, it sounds like testing won't be done until summer and production brass won't be available until late summer early fall. That should give plenty of time to evaluate and see how it stacks up to current offerings.

 

[Sheldon N]

Huh?

Deep breath, deep breath. Now repeat after me....

“I shoot a 6 SLR and I shoot better than all these nerds. I’d rather have a sharp stick in the eye and replace two barrels than do all that math”

There, don’t you feel better? ?

 

[3rd shooter]

I'm really looking forward to see how the round develop's this year. I really hope it is hyper accurate with no feeding issues as promised. It would be great if it really is better than than the Dasher. I'm tired of waiting for good Dasher brass. I for one am looking forward to what it offers in real life. It would be great if it is super accurate like Dasher, low recoil, easy to load, long barrel life and brass that is available. That's a lot to ask but I will hope its true. I personally like the 6mm's and am excited to have another option. Only time will tell how it shakes out. I do have to say I have really been disappointed with the industry support of the Dasher. Its a great round and lots of fun to shoot. Just wish Lapua or Alpha would of supported and help develop it. Maybe even Prime or Hornady sponsor it for commerical production. #1 in PRS last year have to say something. Just my 2 cents. I like Dasher and hope to really like the GAP 6mm GT. I believe in George and for one would like to thank him for bringing this round to market. Thank you Sir for all you have done for the Industry and sport.

 

[Triggerf16]

Dave Tooley has chambered a 6x44 for several years now. Sounds similar. I have no experience with it. But Dave is a smart guy.

Here is the link: http://www.6mmbr.com/gunweek038.html

 

[Milo 2.5]

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.

Trimming 55 thou off to get it running is no big deal. Norma brass for the most part is some of the most consistent brass made, high quality stuff.
But primer pocket retention is not a strong suit of Norma brass, this is probably the biggest reason it won't catch on.

 

[canezach]

Trimming 55 thou off to get it running is no big deal. Norma brass for the most part is some of the most consistent brass made, high quality stuff.
But primer pocket retention is not a strong suit of Norma brass, this is probably the biggest reason it won't catch on.

I have no idea about the life expectancy of the Norma Dasher's primer pockets, since i'm only on my second firing of a batch of 200, but it goes a little further, in my opinion, as to why the Norma brass didn't catch on.

Yes, there's the trimming, which apparently didn't sit well with guys running Lapua chambers, but there was also the need to use a different shell holder because Norma increased the rim thickness to beef up the primer pockets. Then you have the guys running their Dashers at light speed, which I don't think the Norma is quite capable of achieving. I use 32.0 grains of Varget to get into the low 2900s with the 105 Hybrid or 107 SMK. If I go another 0.3 grains higher, I start to run into pressure signs. Guys using Lapua brass are running those same bullets at 3000+. If you tried running the Norma brass at those velocities, you'd be tearing up your brass in a few firings. Personally, i'm fine at 2916 fps, but some guys aren't. That's not even mentioning the need for a Norma reamer if you want to take advantage of the longer neck, which I think is a plus.

I think some people were expecting the Norma brass to be an equal match to Lapua, when in reality, you wouldn't expect that of any other brass maker. My Hornady, Prime, and Alpha 6.5 Creedmoor brass are all different and i've made some incredibly accurate ammo using all three, but I know I can't run the Hornady as hot as I can the Prime, which I can't run as hot as Alpha

 

[TheMammoth]

Considering the fact that you're not the only engineer involved in the discussion and that you completely discount the ideal gas law, I'm going to go ahead and "assure you" that what you're thinking may not be as true as you think.

A pressure spike of 60,000 PSI (max SAAMI average pressure) will cause a fair amount of heat. How much heat?

Case capacity of a 6.5 Creedmoor is approximately 52.5 grains of water, or 3.4 grams meaning the volume is approximately 3.4 milliliters. Approximately 50% of this volume will be taken up by solids (the gunpowder and the bullet, taking into account packing density of gunpowders is less than 100%) meaning we get a gaseous volume of ~1.7 milliliters.

Initial Condition:
101,325 * 0.0017 = n * R * 273.15
n = (101,325 * 0.0034)/(R * 273.15)

Solving for n we get that the original amount of gas in the chamber is approximately 0.07585 moles.

Gunpowder is approximately 75% Potassium Nitrate (KNO3), 15% Charcoal (C), and 10% Sulfur (S). The approximate chemical formula for the burning of gunpowder is as follows:

10 KNO3 + 8 C + 3 S -> 2 K2CO3 + 3 K2SO4 + 6 CO2 + 5 N2, of which Carbon Dioxide and Nitrogen are gasses while Potassium Carbonate and Potassium Sulfate are solids. By a percentage of the weight of the original gunpowder, perfect combustion will create 21.96% CO2, 11.65% N2, and 66.39% solids.

Let's use a standard 6.5 Creedmoor load of 40 grains of powder, which with perfect combustion would create approximately 8.784 grains of Carbon Dioxide and 4.66 grains of Nitrogen gas. This translates to 0.5692 grams of CO2 and 0.302 grams of N2, or 0.0129 moles and 0.0108 moles of the two gasses respectively combining for a total of .0237 moles of gas created by perfect combustion of 40 grains of gunpowder.

This means that the new amount of gas in the chamber after combustion (during the pressure spike) is 0.09955 moles. We also have a new volume since the gunpowder isn't there anymore, meaning the volume is approximately the 3.4 milliliter case capacity. The pressure of 60,000 PSI translates to approximately 413,685,420 pascal.

Post Combustion Condition (60,000 PSI):
413,685,420 * .0034 = 0.09955 * 8.3145 * T
T = (413,685,420 * 0.0034)/(0.09955 * 8.3145)

Our final temperature after the combustion, ignoring the heat from combustion itself, is approximately 1,700,000 degrees Kelvin (1.69931 x 10^6). This translates to 3,059,540 degrees Fahrenheit.

The temperatures realistically experienced in the chamber will be a significant amount lower because combustion is not perfect, nor is it instantaneous, and the volume is constantly expanding - this is an idealized spherical cow in a vacuum type calculation. This is demonstrated by the graphs posted already above.

Do you honestly believe though, in the face of the hard math and the data provided, that there is still no correlation between the temperatures and the pressures experienced within the chamber and throat of the barrel?

Fucking. Rekt. Boi.

 

[Milo 2.5]

I have no idea about the life expectancy of the Norma Dasher's primer pockets, since i'm only on my second firing of a batch of 200, but it goes a little further, in my opinion, as to why the Norma brass didn't catch on.

Yes, there's the trimming, which apparently didn't sit well with guys running Lapua chambers, but there was also the need to use a different shell holder because Norma increased the rim thickness to beef up the primer pockets. Then you have the guys running their Dashers at light speed, which I don't think the Norma is quite capable of achieving. I use 32.0 grains of Varget to get into the low 2900s with the 105 Hybrid or 107 SMK. If I go another 0.3 grains higher, I start to run into pressure signs. Guys using Lapua brass are running those same bullets at 3000+. If you tried running the Norma brass at those velocities, you'd be tearing up your brass in a few firings. Personally, i'm fine at 2916 fps, but some guys aren't. That's not even mentioning the need for a Norma reamer if you want to take advantage of the longer neck, which I think is a plus.

I think some people were expecting the Norma brass to be an equal match to Lapua, when in reality, you wouldn't expect that of any other brass maker. My Hornady, Prime, and Alpha 6.5 Creedmoor brass are all different and i've made some incredibly accurate ammo using all three, but I know I can't run the Hornady as hot as I can the Prime, which I can't run as hot as Alpha

Did not the 2nd batch of Norma brass rectify the rim and shellholder issues? I wasn't that interested in the Norma brass other than neck length(not a bad thing), so I never kept up

 

[canezach]

Did not the 2nd batch of Norma brass rectify the rim and shellholder issues? I wasn't that interested in the Norma brass other than neck length(not a bad thing), so I never kept up

I think so. I bought a few hundred of the first batch when Bullets.com dropped the price because they were releasing the second batch (I think they were calling it F-class or Palma). Then Bullets.com closed shop and discounted the second batch, so I picked 300 of those, but I’ve only been using 200 from the first batch for matches.

 

[bodhisafa]

Small primer?

 

[canezach]

Yes, the Norma Dasher brass is small primer. I'm only on my third firing with the Norma brass, but I have no complaints. My load is either 31.9 or 32.0 grains of Varget, CCI 450 primers, and either the Berger 105 Hybrid or the 107 SMK. MV is low 2900s for either bullet. I don't see a need to run my load to 3000+ fps. I have a 6 Creedmoor barrel for that.

If I get 6 reloads out of the Norma brass, that should put me at 2400 rounds through the barrel, so the barrel will be at or near the end of its life. I'll probably have another barrel or two spun with the Norma chamber and use the rest of the brass

 

[BLKWLFK9]

Werd on da skreet is, lapua will be dropping dasher brass later this year.

 

[bodhisafa]

Sorry gents meant to specify...is the 6GT small primer?

 

[2c1fr]

Going to see what happens with this one

 

[bodhisafa]

I’m looking to have a barrel chambered in it

 

[seafury]

Looks promising. Just ordered a 6BRA on a new impact action so I’ll have fun with that for a while. I may have to check out the GT at some point.

 

[Ranger188]

Sorry per post #88. Got ahold of the Lapua USA parent dist. company, ( Capstone ) and they said
they are looking at this caliber, but at this time have no production date. ( 6 Dasher )
And Alpha isn't either.
Take this anyway you want. I'm not holding my breath for it.

 

[Dthomas3523]

Sorry per post #88. Got ahold of the Lapua USA parent dist. company, ( Capstone ) and they said
they are looking at this caliber, but at this time have no production date.
And Alpha isn't either.
Take this anyway you want. I'm not holding my breath for it.

Not following? George Gardner says Alpha is going to be producing brass for 6GT.

 

[Ranger188]

I'm following, your not. I'm the one who posted Alpha was making 6GT brass (in another thread ))
If you read post #88 it said that word on the street was Lapua was making 6 Dasher brass....

 

[Dthomas3523]

I'm following, your not. I'm the one who posted Alpha was making 6GT brass
If you read post #88 it said that word on the street was Lapua was making 6 Dasher brass....

“You’re” and your post was confusing as shit.

 

[Bender]

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?

Yup definitely an Engineer, pretty sure he passed the “how to be an asshole and condescending at the same time” POLSCI-4400 level at undergraduate level with top honors.

I was a construction superintendent for years, I know the condescension from 1.78 miles away, and have “fixed” many engineers problems. I am not an engineer, I was just a guy on the ground telling the engineer water doesn’t flow up hill, but.... maybe at engineering school they engineered a way to do engineerish black magic where they engineered a cool engineering trick that actually makes water flow up hill, see, but I’m just a dumb guy who lives in a place called “Reality” where I got to spend 15mins on a phone to an engineer explaining that, in fact, water does not flow up hill so well, I didn’t give a flying large-mouse-posterior what his blue prints said.

 

[Dthomas3523]

Yup definitely an Engineer, pretty sure he passed the “how to be an asshole and condescending at the same time” POLSCI-4400 level at undergraduate level with top honors.

I was a construction superintendent for years, I know the condescension from 1.78 miles away, and have “fixed” many engineers problems. I am not an engineer, I was just a guy on the ground telling the engineer water doesn’t flow up hill, but.... maybe at engineering school they engineered a way to do engineerish black magic where in their engineered a cool engineering trick that actually makes water flow up hill, see, but I’m just a dumb guy who lives in a place called “Reality” where I got to spend 15mins on a phone to an engineer explaining that, in fact, water does not flow up hill so well, I didn’t give a flying large-mouse-posterior what his blue prints said.

It does if there’s a pump or the source of water is high enough above......

????

 

[Bender]

It does if there’s a pump or the source of water is high enough above......

????

Shut yer pie hole.......

 

[Codiekfx400]

Is the 6mm gt a srp or lrp?

 

[BLKWLFK9]

SRP

 

[Cody S]

yeah I'm going to stick to my 6 creedmoor using reloder 23 going 3050fps in a 27" barrel.
600 rounds, no sign of wear at all.
definitely recoils harder than a dasher at 2975, which I find odd and it proves to me there is some merit to less powder less recoil.
but again it's a 6mm creed, recoil is mild at worst anyways.
if it was dasher with a longer neck I was going to go for it. looking more and more I think I'll sell my dasher stuff and just use a 6br and 6 creed. 3150fps is easily done with the 110s and a faster powder.

 

[generalzip]

yeah I'm going to stick to my 6 creedmoor using reloder 23 going 3050fps in a 27" barrel.
600 rounds, no sign of wear at all.
definitely recoils harder than a dasher at 2975, which I find odd and it proves to me there is some merit to less powder less recoil.
but again it's a 6mm creed, recoil is mild at worst anyways.
if it was dasher with a longer neck I was going to go for it. looking more and more I think I'll sell my dasher stuff and just use a 6br and 6 creed. 3150fps is easily done with the 110s and a faster powder.

That's exactly what I did. 6BR at 2910 and a 6 creed at 3175 with 105 hybrids. Also have a DTAC load for the creed at 3070.

 

[Nortex]

yeah I'm going to stick to my 6 creedmoor using reloder 23 going 3050fps in a 27" barrel.
600 rounds, no sign of wear at all.
definitely recoils harder than a dasher at 2975, which I find odd and it proves to me there is some merit to less powder less recoil.
but again it's a 6mm creed, recoil is mild at worst anyways.
if it was dasher with a longer neck I was going to go for it. looking more and more I think I'll sell my dasher stuff and just use a 6br and 6 creed. 3150fps is easily done with the 110s and a faster powder.

23 in 6 creed is where it's at. It's a hidden gem of a combination.

 

[ThePretzel]

That's exactly what I did. 6BR at 2910 and a 6 creed at 3175 with 105 hybrids. Also have a DTAC load for the creed at 3070.

You can even get some spicy 6BR DTAC loads if you're motivated. I used a Criteiron pre-fit barrel that was headspaced off of virgin Lapua brass instead of a headspace gauge (tight bore and a tight chamber), and my gun was shooting DTACs at 2850 out of a 28" 6BR barrel without issues. Bolt lift got heavy when velocities got to the 2900 fps mark. My 105 hybrid load fast too, above 2950 fps, for that barrel.

Then again, that was a barrel where I just wanted to see what kind of performance the 6BR could crank out with a setup near-optimized for speed.

 

[tsu45]

Is the 6mm gt a srp or lrp?

99% SWAG that it will be small

 

[lte82]

If a dasher takes 33.5 gr varget, a 6gt 34-34.5 varget, and a 6x47 takes 35.5 gr varget to all go 3050, how significantly different are they going to be recoil and barrel life wise? Seems the trade is peak pressure for a couple grains less powder...

 

[Eric_F]

If a dasher takes 33.5 gr varget, a 6gt 34-34.5 varget, and a 6x47 takes 35.5 gr varget to all go 3050, how significantly different are they going to be recoil and barrel life wise? Seems the trade is peak pressure for a couple grains less powder...

Collisions (or repulsions if you reverse time) can be anywhere on a scale from perfectly elastic (all kinetic energy conserved) or perfectly inelastic (max kinetic energy lost) but in either case momentum is always conserved. And a cartridge igniting is literally a textbook example of an inelastic repulsion. This is because so much energy is dispersed as heat, light, and sound. All of which is to say just calculate the momentum and its easy to compare loads.

The recoil momentum imparted to a rifle from a shot will be (bullet mass)*(bullet velocity) + (powder mass) * (powder/gas velocity). How you estimate average powder/ignition gas velocity I'm not sure, and surely varies by muzzle device. I'll just simplify and say equal to the bullet, which would be like a bare muzzle, so max difference between them.

Assuming those speeds with 105 gr bullets, bullet momentum for all is:
3050 ft/s * (105 gr / 7000 lb/gr) = 45.75 ft-lb/s
The difference is all in powder/ignition gas momentum:

6 Dasher - 3050 fps * (33.5 gr / 7000 lb/gr) = 14.59 ft-lb/s, 60.34 ft-lb/s total

6 GT - 3050 fps * (34.25 gr / 7000 lb/gr) = 14.92 ft-lb/s, 60.67 ft-lb/s total

6x47 - 3050 fps * (35.5 gr / 7000 lb/gr) = 15.47 ft-lb/s, 61.22 ft-lb/s total

So that seems like really minor differences to me. In reality, anyone shooting these is likely to have a very effective brake as well, so maybe half or less of the gas is going that speed, so even less momentum would be imparted and there would be even less difference between the cartridges. Finally, how momentum of the rifle (with constant weight, this also equates to a free-recoil velocity) corresponds to felt recoil is a good question but it's at least a solid starting point and more straightforward with a bolt action than a semi-auto.

Brass availability, ease of reloading, and any barrel life differences seem like the larger differences here.

 

[Ranger188]

I've got to think putting 34g of powder (22GT) compared to 42g of powder (22 Creed)
that the 22 GT would be a better choice and have a longer barrel life and easier on other components.
I'll let you know how many rounds I get out of my 22 creed. Have almost 300 now and started with
RL26 and now using RL23 and see a little fire cracking beginning.
If if you don't believe in all the hype, the 6GT already has factory brass, (eventually Alpha)
something the 6 Dasher and 6 BRA don't. If it get's a little kick in the ass, it might surpass those two
from the drive by's that don't reload at first. Look at the 6.5 Creedmoor. Great marketing job their.

 

[kthomas]

I've got to think putting 34g of powder (22GT) compared to 42g of powder (22 Creed)
that the 22 GT would be a better choice and have a longer barrel life and easier on other components.
I'll let you know how many rounds I get out of my 22 creed. Have almost 300 now and started with
RL26 and now using RL23 and see a little fire cracking beginning.
If if you don't believe in all the hype, the 6GT already has factory brass, (eventually Alpha)
something the 6 Dasher and 6 BRA don't. If it get's a little kick in the ass, it might surpass those two
from the drive by's that don't reload at first. Look at the 6.5 Creedmoor. Great marketing job their.

George has done a great job getting factory support for his new cartridge. Really wouldn't surprise me if it took off and starts to become one of the more popular cartridges in the next few PRS seasons.

Fireforming 6BRA is incredibly easy, and the FF loads are more than accurate enough to shoot in comps. However, I can see why some would be deterred by the FF step and would rather jump on the 6GT ship to skip the whole FF process.

 

[Sheldon N]

To me, the only advantage is a little extra capacity to run 4350. I'm at 35gr in the Dasher pushing 105's at 2900. I'm fine with the speed, it's just compressed. I've tried to get away from Varget in cartridges of that size bc it is a throat torcher. In 300rds on my new Dasher barrel 4350 has already demonstrated an erosion rate about a 1/3 of what Varget would normally produce. IMO this cartridge will dissapoint if a person is going to to try to emulate the performance of the bigger 6's with somehow better barrel life. I think a shooter would be happier "right-sizing" it's performance and shooters expectation in the company it keeps (Dasher world: low end 2900's with low recoil).

I wonder if it's more about the pressure you run rather than the powder itself? I have some friends who say they want to go from H4350 to Varget because it's easier on the throats lol. No experience myself with 4350, but it's interesting to see those differing perspectives. Personally I think pressure and total powder quantity are the two biggest factors.

I wonder which would give better barrel life with a 105 Hybrid at 2900... a 6BRA or a down-loaded 6GT with H4350?

 

[spife7980]

but I'm betting folks that are running over 32gr of Varget in a Dasher and over 2950 are running well over 60Kpsi. Ive heard guys talk about running Dashers at over 3000fps. They've got to be close to 70K psi.

I agree. In my 105 rdf testing I read all sorts of wonder loads for high 32s to mid 33s so made my test from 32-33.8 gr varget and bullets .020 off the lands thinking I would skip ahead to the good zone.

I started my testing at 32 gr which got me 2930 fps and it was fine extracting. 32.2 got me 2942 and started to get ever so slight heavy bolt lift on one. Not believing my lying eyes I continued to shoot my series going up to 33 grains in .2 increments. At this point on 33 it was 3009 fps there was unmistakable heavy bolt lift with heavy ejector marks and I was no longer brave enough to keep exploring and I pulled bullets on those charges which were higher.
32.4 was really where I should have called it quits when I first started noticing the issues.

 

[Ranger188]

Haven't seen too many pictures of the 6GT case, but here's one next to a 6.5 Creed

 

[Eric_F]

To me, both 6 BRA and 6 GT seem like great options with little separating them. Dasher seems like too much work in brass prep, and I haven't heard great things about the Norma brass.

6 BRA has essentially factory brass (given how easy and accurate fireforming is), and it's Lapua. Seating dies are easy as they're Dasher, the only hangup is the sizing die is custom. And then mag kits are needed, an added expense for AICS but non existent for other platforms (I'm a special snowflake who likes Tikkas and CTR mags).

6 GT will soon have Alpha brass, which I've heard is comparable if not quite Lapua quality. Dies are available now from Hornady, and soon Redding. No mag kits needed is a plus for sure. Enough case capacity for respectable velocities with 110 and 115 gr would be good too. The tradeoff being more recoil or less barrel life.

Assuming the suppliers are there as promised, I'll be going 6 GT.

 

[Capt Academy]

yeah I'm going to stick to my 6 creedmoor using reloder 23 going 3050fps in a 27" barrel.
600 rounds, no sign of wear at all.
definitely recoils harder than a dasher at 2975, which I find odd and it proves to me there is some merit to less powder less recoil.
but again it's a 6mm creed, recoil is mild at worst anyways.
if it was dasher with a longer neck I was going to go for it. looking more and more I think I'll sell my dasher stuff and just use a 6br and 6 creed. 3150fps is easily done with the 110s and a faster powder.

How many grains of RL-23 are you using in your 6 Creed?

 

[Aaron47pb]

To me, both 6 BRA and 6 GT seem like great options with little separating them. Dasher seems like too much work in brass prep, and I haven't heard great things about the Norma brass.

6 BRA has essentially factory brass (given how easy and accurate fireforming is), and it's Lapua. Seating dies are easy as they're Dasher, the only hangup is the sizing die is custom. And then mag kits are needed, an added expense for AICS but non existent for other platforms (I'm a special snowflake who likes Tikkas and CTR mags).

6 GT will soon have Alpha brass, which I've heard is comparable if not quite Lapua quality. Dies are available now from Hornady, and soon Redding. No mag kits needed is a plus for sure. Enough case capacity for respectable velocities with 110 and 115 gr would be good too. The tradeoff being more recoil or less barrel life.

Assuming the suppliers are there as promised, I'll be going 6 GT.

How is Dasher “brass prep” any different from 6BRA “brass prep”?