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Range Report 260 rem vs 260 ackley
- Thread starter Ryanar15
- Start date
Re: 260 rem vs 260 ackley
I like to keep it simple, so I prefer a 260 Rem with the 140 VLD's. When you have an AI, you have to fire form your brass, which is one more step that takes time, bullets, powder, and primers. You'll gain a little velocity, but IMO not worth the extra effort. And it would suck loosing brass at a match!
I like to keep it simple, so I prefer a 260 Rem with the 140 VLD's. When you have an AI, you have to fire form your brass, which is one more step that takes time, bullets, powder, and primers. You'll gain a little velocity, but IMO not worth the extra effort. And it would suck loosing brass at a match!
Re: 260 rem vs 260 ackley
About 50 FPS............ Nothing wrong with a standard 260. And yes I have had both.
About 50 FPS............ Nothing wrong with a standard 260. And yes I have had both.
Re: 260 rem vs 260 ackley
I had both also. The AI netted me 50-100 fps with the same charge weight, depending on which powder I used, slower powder= more gain.
This was with the same barrel, but one inch shorter barrel length on the AI. Cut the tenon off and re-chambered to AI after 1700 rounds of standard 260 down the barrel.
I had both also. The AI netted me 50-100 fps with the same charge weight, depending on which powder I used, slower powder= more gain.
This was with the same barrel, but one inch shorter barrel length on the AI. Cut the tenon off and re-chambered to AI after 1700 rounds of standard 260 down the barrel.
Re: 260 rem vs 260 ackley
Fireforming isn't as bad as its made out to be. I get excellent accuracy in my 6mm Crusader fireforming loads. My buddy gets excellent accuracy fireforming his 260AI cases. If you spend a little time working the fireforming load, you can find accuracy with it. Then its no longer a chore, its just another load. One where you only get the performance of the parent caliber.
Fireforming isn't as bad as its made out to be. I get excellent accuracy in my 6mm Crusader fireforming loads. My buddy gets excellent accuracy fireforming his 260AI cases. If you spend a little time working the fireforming load, you can find accuracy with it. Then its no longer a chore, its just another load. One where you only get the performance of the parent caliber.
Re: 260 rem vs 260 ackley
Fireforming is not an issue for me. I make my .260 brass by running Win .243 brass through the F/L resizer. Aside from flash hole reaming, that's my whole brass prep program.
My first loading is just that, loading with a standard load.
AI's have seldom made sense to me. A) most AI's have a corresponding chambering that requires no case forming. B) most AI's are made to increase case capacity, and like as not, that case capacity is going to get used. Effectively it's hotloading, but with some allowance to increase the case capacity and avoid catastrophe. My point is that catastrophe or not, the chambering is being driven at or beyond original capability, and that's simply <span style="font-style: italic">got</span> to have throat life issues.
If you feel the .260's not enough, what you really need is a 6.5x55, and if that won't do it, there's the 6.5-284...
AI? Naaah!
Greg
Fireforming is not an issue for me. I make my .260 brass by running Win .243 brass through the F/L resizer. Aside from flash hole reaming, that's my whole brass prep program.
My first loading is just that, loading with a standard load.
AI's have seldom made sense to me. A) most AI's have a corresponding chambering that requires no case forming. B) most AI's are made to increase case capacity, and like as not, that case capacity is going to get used. Effectively it's hotloading, but with some allowance to increase the case capacity and avoid catastrophe. My point is that catastrophe or not, the chambering is being driven at or beyond original capability, and that's simply <span style="font-style: italic">got</span> to have throat life issues.
If you feel the .260's not enough, what you really need is a 6.5x55, and if that won't do it, there's the 6.5-284...
AI? Naaah!
Greg
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SilentStrike</div><div class="ubbcode-body">can i get 3000 to 4000 rounds of barrel life with a 260 rem
</div></div>
You will not have the needed accuracy for target shooting with that many rounds. Especially if you shoot F-class or other matches with 20 round strings. Figure 2,500, YMMV
Good luck
Jerry
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SilentStrike</div><div class="ubbcode-body">can i get 3000 to 4000 rounds of barrel life with a 260 rem
</div></div>
You will not have the needed accuracy for target shooting with that many rounds. Especially if you shoot F-class or other matches with 20 round strings. Figure 2,500, YMMV
Good luck
Jerry
Re: 260 rem vs 260 ackley
I think the 2500 round estimate is very close to reality. After 1000rd, some borescoping, plus comparing seating depths and throat migration, I discussed this with the L-W customer service folks and their estimate was 2400.
That was shooting 142SMK at 2800fps using a a load that was about .5 to 1.0gr below published max.
I don't shoot 1000yd anymore, and do FV200 matches twice a month. I am now shooting 95gr V-Max with a near min charge of propellant.
My expectation is that this will add a considerable number of rounds to the bore/throat life projection.
Greg
I think the 2500 round estimate is very close to reality. After 1000rd, some borescoping, plus comparing seating depths and throat migration, I discussed this with the L-W customer service folks and their estimate was 2400.
That was shooting 142SMK at 2800fps using a a load that was about .5 to 1.0gr below published max.
I don't shoot 1000yd anymore, and do FV200 matches twice a month. I am now shooting 95gr V-Max with a near min charge of propellant.
My expectation is that this will add a considerable number of rounds to the bore/throat life projection.
Greg
Re: 260 rem vs 260 ackley
Depends on how you plan to use rifle and what contour barrel used.
I've seen several 260s with HV contour barrels, used on tactical rifle for practice & match, that made it to 1800 - 2000 rds before LR performance wasn't acceptable.
I've also seen several 260s with #5/6 sporter contour barrels, tactical rifle for practice and match, that made 1300ish rds before LR performance wasn't acceptable.
If you never run strings of fire greater that 10 rounds, never shoot barrel hot......barrel will last longer but since I rarely/never use my rifles in that fashion I couldn't give you a good estimate of barrel life.
Tactical rifle matches and/or F-class matches I'd plan on 2000 rds before needing a new barrel to maintain sub MOA accuracy at 1K.
Depends on how you plan to use rifle and what contour barrel used.
I've seen several 260s with HV contour barrels, used on tactical rifle for practice & match, that made it to 1800 - 2000 rds before LR performance wasn't acceptable.
I've also seen several 260s with #5/6 sporter contour barrels, tactical rifle for practice and match, that made 1300ish rds before LR performance wasn't acceptable.
If you never run strings of fire greater that 10 rounds, never shoot barrel hot......barrel will last longer but since I rarely/never use my rifles in that fashion I couldn't give you a good estimate of barrel life.
Tactical rifle matches and/or F-class matches I'd plan on 2000 rds before needing a new barrel to maintain sub MOA accuracy at 1K.
Re: 260 rem vs 260 ackley
There's a few advantages to AI'ing a case and as always a few caveats. Of the advantages is first the increased capacity. Unless you use a slow enough powder and have a long enough barrel to use the hot gases, that isn't all that great of an advantage.
The increased shoulder angle is what usually gives most of the capacity advantage. The other thing it really does, good or bad, is create sort of a dynamic pressure dam. As powder is ignited in the case and pressure moves forward it is slowed by the sharper angle of the shoulder causing higher pressures to build. Momentarily of course. So, the shoulder angle giving increased capacity kind of works hand in hand in some cases. In some cases the increased pressure restricts flow of the ignited plasma. So, maybe it's not always a great idea to go with a 40 deg. shoulder. The WSSM's and WSM all work on the fatter cartridge theory and stayed in the 30-35 deg. range. Therefore, my opinion, having loaded AI's from .17 up to .375, is that the larger the diameter the more angle you can have. Having a sharp shoulder on a small diameter is counter productive. A .260 could have a .35 degree shoulder. Better flow....
The other thing an AI gets you is the shoulder blown out to make the case walls straighter. This allows the case to better grip the walls of the chamber while the firing process takes place. Basically, it helps reduce bolt thrust. And, helps increase brass life. That is if you're not trying to push the round to it's absolute limit. I've seen some AI cases fired from a tight chamber go more than 30 reloads. I generally consider this to be the more productive reason to cut an AI chamber.
Cutting an AI chamber is great when it comes to high taper cases like the .250 Savage and all the Mauser cases Ackley improved. But, the .260 is only getting .005" bigger at the shoulder. Not much gain there. Any case based off the .308 isn't going to get a whole lot of improvement by going this route. But, some of the same guys I shoot with up north say it's the best way to go for extended accuracy of cases and barrels. Use slower powder loads and let the steep shoulders do their work. And don't load so hot you trash the brass...because if you do, it's pointless.
There's a few advantages to AI'ing a case and as always a few caveats. Of the advantages is first the increased capacity. Unless you use a slow enough powder and have a long enough barrel to use the hot gases, that isn't all that great of an advantage.
The increased shoulder angle is what usually gives most of the capacity advantage. The other thing it really does, good or bad, is create sort of a dynamic pressure dam. As powder is ignited in the case and pressure moves forward it is slowed by the sharper angle of the shoulder causing higher pressures to build. Momentarily of course. So, the shoulder angle giving increased capacity kind of works hand in hand in some cases. In some cases the increased pressure restricts flow of the ignited plasma. So, maybe it's not always a great idea to go with a 40 deg. shoulder. The WSSM's and WSM all work on the fatter cartridge theory and stayed in the 30-35 deg. range. Therefore, my opinion, having loaded AI's from .17 up to .375, is that the larger the diameter the more angle you can have. Having a sharp shoulder on a small diameter is counter productive. A .260 could have a .35 degree shoulder. Better flow....
The other thing an AI gets you is the shoulder blown out to make the case walls straighter. This allows the case to better grip the walls of the chamber while the firing process takes place. Basically, it helps reduce bolt thrust. And, helps increase brass life. That is if you're not trying to push the round to it's absolute limit. I've seen some AI cases fired from a tight chamber go more than 30 reloads. I generally consider this to be the more productive reason to cut an AI chamber.
Cutting an AI chamber is great when it comes to high taper cases like the .250 Savage and all the Mauser cases Ackley improved. But, the .260 is only getting .005" bigger at the shoulder. Not much gain there. Any case based off the .308 isn't going to get a whole lot of improvement by going this route. But, some of the same guys I shoot with up north say it's the best way to go for extended accuracy of cases and barrels. Use slower powder loads and let the steep shoulders do their work. And don't load so hot you trash the brass...because if you do, it's pointless.
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: apache kid</div><div class="ubbcode-body">Why not just load down a 6.5-284 to lower pressures?
</div></div>
My WAG on this is that you don't get the accuracy you're looking for.
If you load less powder to lower pressures, then you will have diminished load density, which can effect your ES and SD.
If you load more slower burning powder to lower pressures, you get +100% load density but don't develop enough pressure to get a full burn, which effects your ES and SD.
Also to equal .260Rem performance in a 6.5x284 case, you will still have to burn more powder than in a .260Rem case.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: apache kid</div><div class="ubbcode-body">Why not just load down a 6.5-284 to lower pressures?
</div></div>
My WAG on this is that you don't get the accuracy you're looking for.
If you load less powder to lower pressures, then you will have diminished load density, which can effect your ES and SD.
If you load more slower burning powder to lower pressures, you get +100% load density but don't develop enough pressure to get a full burn, which effects your ES and SD.
Also to equal .260Rem performance in a 6.5x284 case, you will still have to burn more powder than in a .260Rem case.
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">to equal .260Rem performance in a 6.5x284 case, you will still have to burn more powder than in a .260Rem case</div></div>
What is going to effect throat life more?
An extra 5 to 6 grains of powder or an extra 5k to 6k psi?
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">If you load more slower burning powder to lower pressures, you get +100% load density but don't develop enough pressure to get a full burn, which effects your ES and SD.</div></div>
I'm not sure I follow you on this,
A full burn, it's a fact that all your powder is burned within 2" to 3" of your chamber.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">to equal .260Rem performance in a 6.5x284 case, you will still have to burn more powder than in a .260Rem case</div></div>
What is going to effect throat life more?
An extra 5 to 6 grains of powder or an extra 5k to 6k psi?
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">If you load more slower burning powder to lower pressures, you get +100% load density but don't develop enough pressure to get a full burn, which effects your ES and SD.</div></div>
I'm not sure I follow you on this,
A full burn, it's a fact that all your powder is burned within 2" to 3" of your chamber.
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: apache kid</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">to equal .260Rem performance in a 6.5x284 case, you will still have to burn more powder than in a .260Rem case</div></div>
What is going to effect throat life more?
An extra 5 to 6 grains of powder or an extra 5k to 6k psi?
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">If you load more slower burning powder to lower pressures, you get +100% load density but don't develop enough pressure to get a full burn, which effects your ES and SD.</div></div>
I'm not sure I follow you on this,
A full burn, it's a fact that all your powder is burned within 2" to 3" of your chamber.
</div></div>
Personally, I would say the extra 5-6K of pressure wears out throats faster.
Also, all the powder is ignited and pretty much vaporized in the first 2"-3", but it's not done burning (chemically combining). Rapid oxidation is still occurring almost as long as you have expanding gases. Which is usually to the end of the barrel if not farther. Decompression at the muzzle of the barrel eliminates the continued process if there is unburned "fuel". Shoot a gun at night if you don't believe that. And, then tell me what muzzle flash is.
Burning slower powder works in an AI case because of the "pressure dam" dynamics. You can't just load a slower powder in a case and expect it to work better. As buffybuster said you won't get enough push initally to get the bullet going fast enough. You may need to go to a high pressure powder, like Alliant and VV 500 series powders. It takes a little playing with but many AI cases do work well once you get them tuned in.
The interesting thing is the 6.5-284 has a steep shoulder already. So it takes to a slower powder a little better I think than does the .260 Rem case. Sometimes we all feel the need to find our own way in this and as was suggested before you could go to a 6.5x55 Swede. That will only gain you about 2-3 gr. over the .260. But, if you went with the 6.5x55 AI you could get the good brass, Lapua. And increase your capacity as well by about 10 gr.
An item of note regarding that, the 6.5-284 has almost 30-06 case capacity in water (64 gr.). A full length Mauser case (7x57, 8x57) has about 57 gr. water capacity and 61 when AI'd. The 6.5x55 has 54 and 60-61 when AI'd. The .260 has about 51 and 55 gr. That's all water up to the top of the neck. To find out what your actual capacity would be fill a fired case and slip a bullet down to where you would seat it and then pull the bullet and weigh it.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: apache kid</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">to equal .260Rem performance in a 6.5x284 case, you will still have to burn more powder than in a .260Rem case</div></div>
What is going to effect throat life more?
An extra 5 to 6 grains of powder or an extra 5k to 6k psi?
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">If you load more slower burning powder to lower pressures, you get +100% load density but don't develop enough pressure to get a full burn, which effects your ES and SD.</div></div>
I'm not sure I follow you on this,
A full burn, it's a fact that all your powder is burned within 2" to 3" of your chamber.
</div></div>
Personally, I would say the extra 5-6K of pressure wears out throats faster.
Also, all the powder is ignited and pretty much vaporized in the first 2"-3", but it's not done burning (chemically combining). Rapid oxidation is still occurring almost as long as you have expanding gases. Which is usually to the end of the barrel if not farther. Decompression at the muzzle of the barrel eliminates the continued process if there is unburned "fuel". Shoot a gun at night if you don't believe that. And, then tell me what muzzle flash is.
Burning slower powder works in an AI case because of the "pressure dam" dynamics. You can't just load a slower powder in a case and expect it to work better. As buffybuster said you won't get enough push initally to get the bullet going fast enough. You may need to go to a high pressure powder, like Alliant and VV 500 series powders. It takes a little playing with but many AI cases do work well once you get them tuned in.
The interesting thing is the 6.5-284 has a steep shoulder already. So it takes to a slower powder a little better I think than does the .260 Rem case. Sometimes we all feel the need to find our own way in this and as was suggested before you could go to a 6.5x55 Swede. That will only gain you about 2-3 gr. over the .260. But, if you went with the 6.5x55 AI you could get the good brass, Lapua. And increase your capacity as well by about 10 gr.
An item of note regarding that, the 6.5-284 has almost 30-06 case capacity in water (64 gr.). A full length Mauser case (7x57, 8x57) has about 57 gr. water capacity and 61 when AI'd. The 6.5x55 has 54 and 60-61 when AI'd. The .260 has about 51 and 55 gr. That's all water up to the top of the neck. To find out what your actual capacity would be fill a fired case and slip a bullet down to where you would seat it and then pull the bullet and weigh it.
Re: 260 rem vs 260 ackley
I appreciate your post,
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Shoot a gun at night if you don't believe that. And, then tell me what muzzle flash is.</div></div>
From my understanding,
The ball of flame is the hot gas from the powder reigniting when it hits the oxygen of the atmosphere, not still-burning powder.
I appreciate your post,
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Shoot a gun at night if you don't believe that. And, then tell me what muzzle flash is.</div></div>
From my understanding,
The ball of flame is the hot gas from the powder reigniting when it hits the oxygen of the atmosphere, not still-burning powder.
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: apache kid</div><div class="ubbcode-body">I appreciate your post,
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Shoot a gun at night if you don't believe that. And, then tell me what muzzle flash is.</div></div>
From my understanding,
The ball of flame is the hot gas from the powder reigniting when it hits the oxygen of the atmosphere, not still-burning powder.
</div></div>
That too. Either way it's un-oxidized content still in hot mode. I think of it like a firestorm (if you've ever seen one) where trees and brush vaporize and that content goes up. But you don't see the bright orange flame until it gets a couple hundred feet off the ground. Powder as ignited moves down the barrel as a gas releasing it's own oxygen and creating pressure in a rapidly expanding volume (chamber and bore). At some point the oxidation material runs out but hot gases containing combustables within it do re-ignite when fresh oxygen is introduced. But, this situation requires high pressure to keep the ignition going.
Anyhow, another way to watch this work is shoot paper from 5 yds. or less, then look for powder burns. As the unburned powder particulates congeal in the cooler air and then hit the paper. This is really noticeable in straight-walled cartridges out of pistols. Still using smokeless powder of course.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: apache kid</div><div class="ubbcode-body">I appreciate your post,
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Shoot a gun at night if you don't believe that. And, then tell me what muzzle flash is.</div></div>
From my understanding,
The ball of flame is the hot gas from the powder reigniting when it hits the oxygen of the atmosphere, not still-burning powder.
</div></div>
That too. Either way it's un-oxidized content still in hot mode. I think of it like a firestorm (if you've ever seen one) where trees and brush vaporize and that content goes up. But you don't see the bright orange flame until it gets a couple hundred feet off the ground. Powder as ignited moves down the barrel as a gas releasing it's own oxygen and creating pressure in a rapidly expanding volume (chamber and bore). At some point the oxidation material runs out but hot gases containing combustables within it do re-ignite when fresh oxygen is introduced. But, this situation requires high pressure to keep the ignition going.
Anyhow, another way to watch this work is shoot paper from 5 yds. or less, then look for powder burns. As the unburned powder particulates congeal in the cooler air and then hit the paper. This is really noticeable in straight-walled cartridges out of pistols. Still using smokeless powder of course.
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">then look for powder burns. As the unburned powder particulates congeal in the cooler air and then hit the paper.</div></div>
True, but is this not powder that would not burn anyways?
For lack of better words, it's dead powder from the case to the ground. It never was going to ignite.
I am still trying to figure all this out, my questions are not challenges so to speak.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">then look for powder burns. As the unburned powder particulates congeal in the cooler air and then hit the paper.</div></div>
True, but is this not powder that would not burn anyways?
For lack of better words, it's dead powder from the case to the ground. It never was going to ignite.
I am still trying to figure all this out, my questions are not challenges so to speak.
Re: 260 rem vs 260 ackley
What you want to occur is the majority of the powder to be ignited within the case and be consumed within the first 1-2" of the throat maintains an optimal pressure to volume ratio. That will provide a consistent pressure curve.
If the powder is too slow for the case capacity, the primer will only ignite a portion of the powder in the case and the pressure wave will push the powder into the throat and burn in the 2-4" of the barrel. This large increase in volume will result in a less consistent pressure curve.
What you want to occur is the majority of the powder to be ignited within the case and be consumed within the first 1-2" of the throat maintains an optimal pressure to volume ratio. That will provide a consistent pressure curve.
If the powder is too slow for the case capacity, the primer will only ignite a portion of the powder in the case and the pressure wave will push the powder into the throat and burn in the 2-4" of the barrel. This large increase in volume will result in a less consistent pressure curve.
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: apache kid</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">then look for powder burns. As the unburned powder particulates congeal in the cooler air and then hit the paper.</div></div>
True, but is this not powder that would not burn anyways?
For lack of better words, it's dead powder from the case to the ground. It never was going to ignite.
I am still trying to figure all this out, my questions are not challenges so to speak.</div></div>
Per your first paragraph, a lot depends on the efficiency of the case/bullet/rifle set-up. It might not have been dead powder if the case was more efficient. A classic example of an inefficient round is the .30-30. It doesn't burn much powder but it doesn't put stuff out near as fast as other cases of equal capacity. I credit the shallow shoulder. On the other hand look at the 6 BR. Lots of velocity in that little case (of about the same size as the 30-30. And if you look at cases when they are done firing...the 6BR usually has a lot less junk in it.
As to the second part of your post, it's good to challenge. Even those who seek to teach you. If you don't understand something and the guy telling to you only tells you once, or doesn't tell it all, how are you going to know if you don't put it back to him and ask? So don't worry about challenging.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: apache kid</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">then look for powder burns. As the unburned powder particulates congeal in the cooler air and then hit the paper.</div></div>
True, but is this not powder that would not burn anyways?
For lack of better words, it's dead powder from the case to the ground. It never was going to ignite.
I am still trying to figure all this out, my questions are not challenges so to speak.</div></div>
Per your first paragraph, a lot depends on the efficiency of the case/bullet/rifle set-up. It might not have been dead powder if the case was more efficient. A classic example of an inefficient round is the .30-30. It doesn't burn much powder but it doesn't put stuff out near as fast as other cases of equal capacity. I credit the shallow shoulder. On the other hand look at the 6 BR. Lots of velocity in that little case (of about the same size as the 30-30. And if you look at cases when they are done firing...the 6BR usually has a lot less junk in it.
As to the second part of your post, it's good to challenge. Even those who seek to teach you. If you don't understand something and the guy telling to you only tells you once, or doesn't tell it all, how are you going to know if you don't put it back to him and ask? So don't worry about challenging.
Re: 260 rem vs 260 ackley
Ideally all the powder would be consumed in the case but that doesn't occur with our current methods. So the next best thing would be to try and maximize the amount of powder consumed within the case (by efficient case geometry) and the remaining powder within a short distance in the throat.
In the past there were some experiments involving front ignition which ignited the powder just under the bullet and it "burned" back to the casehead. Results were generally favorable but inconclusive due to some manufacturing inconsistencies. I don't think it got past the experimental stage in small arms.
Ideally all the powder would be consumed in the case but that doesn't occur with our current methods. So the next best thing would be to try and maximize the amount of powder consumed within the case (by efficient case geometry) and the remaining powder within a short distance in the throat.
In the past there were some experiments involving front ignition which ignited the powder just under the bullet and it "burned" back to the casehead. Results were generally favorable but inconclusive due to some manufacturing inconsistencies. I don't think it got past the experimental stage in small arms.
Re: 260 rem vs 260 ackley
260, but you can burn that up fast as well as the .260 AI {edit: by loading them as hot as they'll go}. You could, I would expect get 2k-3k rounds out of it good enough for competition.
Now, if you go really easy on your barrels like I do...I just topped 2k in my 7x57 and it's just starting to show erosion. It has at least another 2k if not 4k to go before it wears out at that rate.
260, but you can burn that up fast as well as the .260 AI {edit: by loading them as hot as they'll go}. You could, I would expect get 2k-3k rounds out of it good enough for competition.
Now, if you go really easy on your barrels like I do...I just topped 2k in my 7x57 and it's just starting to show erosion. It has at least another 2k if not 4k to go before it wears out at that rate.
Re: 260 rem vs 260 ackley
Results of 50 grains of slower RL 25 powder in the 260 Rem.
COAL 2.825 22" barrel
Results of 50 grains of slower RL 25 powder in the 260 Rem.
COAL 2.825 22" barrel
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sandwarrior</div><div class="ubbcode-body">
Burning slower powder works in an AI case because of the "pressure dam" dynamics. You can't just load a slower powder in a case and expect it to work better. As buffybuster said you won't get enough push initally to get the bullet going fast enough. You may need to go to a high pressure powder, like Alliant and VV 500 series powders. It takes a little playing with but many AI cases do work well once you get them tuned in.
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If you are referencing that statement I made a few posts back, how do other powders like VV N160 and H4350X , VV N560, and RE-19/22 work behind that bullet? I'm thinking a little better velocity?
Nice group by the way!
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sandwarrior</div><div class="ubbcode-body">
Burning slower powder works in an AI case because of the "pressure dam" dynamics. You can't just load a slower powder in a case and expect it to work better. As buffybuster said you won't get enough push initally to get the bullet going fast enough. You may need to go to a high pressure powder, like Alliant and VV 500 series powders. It takes a little playing with but many AI cases do work well once you get them tuned in.
</div></div>
If you are referencing that statement I made a few posts back, how do other powders like VV N160 and H4350X , VV N560, and RE-19/22 work behind that bullet? I'm thinking a little better velocity?
Nice group by the way!
Re: 260 rem vs 260 ackley
My theory (I said theory) on dealing with the pressure dam concept is to use a primer with sufficient brisance to punch through the length of the powder column and reach to the base of the cartridge.
In theory, this ignites the entire central core of the charge, driving the rest of the charge outward against the casewall. The charge then burns radially (from central axis toward the casewall), largely restricting the central core as a passage for the exit of gas.
In theory, a sharper (more perpendicular to the bore axis) shoulder angle aids in this process.
Greg
My theory (I said theory) on dealing with the pressure dam concept is to use a primer with sufficient brisance to punch through the length of the powder column and reach to the base of the cartridge.
In theory, this ignites the entire central core of the charge, driving the rest of the charge outward against the casewall. The charge then burns radially (from central axis toward the casewall), largely restricting the central core as a passage for the exit of gas.
In theory, a sharper (more perpendicular to the bore axis) shoulder angle aids in this process.
Greg
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">My theory (I said theory) on dealing with the pressure dam concept is to use a primer with sufficient brisance to punch through the length of the powder column and reach to the base of the cartridge.
<span style="font-weight: bold">In theory, this ignites the entire central core of the charge, driving the rest of the charge outward against the casewall. The charge then burns radially (from central axis toward the casewall), largely restricting the central core as a passage for the exit of gas.
In theory, a sharper (more perpendicular to the bore axis) shoulder angle aids in this process.</span>
Greg</div></div>
In theory that is how it is supposed to work. However, what always happens is that ignition goes upward in a cone. How high and how sharp depends a lot on powder choice and primer as well as temp outside.
In perfect theory this would predicate the use of a faster powder. Unfortunately faster powders don't fill the larger improved cases giving little advantage to them. Use of a magnum primer and slower powder is the only way to make this work. This does give the steeper cone and the outward radial burn. My only problem with this is the lower corners actually ignite slower and don't come into play as areas that produce highly productive pressure. They produce productive pressure, just not as much.
However, I take the different route in that I'm trying to ignite the base of the powder stack and burn forward. I achieve this best in lower volume cases. A medium burning powder replaces the fast burning powder. As the base gets ignited and pressure builds it pushes the entire stack against the shoulder increasing pressure and thus decreasing burn time. If all goes well the entire column is ignited by the time the last powder hits the end of the neck. And the major push on the bullet is just after it leaves the neck. With larger cases I rarely bump up much in powder speed. As in the .280 Rem to .280 Ackley I went from using 4350 to 4831. H1000 was too slow. Re-17 has come along and changed a lot of that. With the burn retardant properties it's actually affected how you want to attain speed, not just keep from accidentally blowing up your firearm...and you.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">My theory (I said theory) on dealing with the pressure dam concept is to use a primer with sufficient brisance to punch through the length of the powder column and reach to the base of the cartridge.
<span style="font-weight: bold">In theory, this ignites the entire central core of the charge, driving the rest of the charge outward against the casewall. The charge then burns radially (from central axis toward the casewall), largely restricting the central core as a passage for the exit of gas.
In theory, a sharper (more perpendicular to the bore axis) shoulder angle aids in this process.</span>
Greg</div></div>
In theory that is how it is supposed to work. However, what always happens is that ignition goes upward in a cone. How high and how sharp depends a lot on powder choice and primer as well as temp outside.
In perfect theory this would predicate the use of a faster powder. Unfortunately faster powders don't fill the larger improved cases giving little advantage to them. Use of a magnum primer and slower powder is the only way to make this work. This does give the steeper cone and the outward radial burn. My only problem with this is the lower corners actually ignite slower and don't come into play as areas that produce highly productive pressure. They produce productive pressure, just not as much.
However, I take the different route in that I'm trying to ignite the base of the powder stack and burn forward. I achieve this best in lower volume cases. A medium burning powder replaces the fast burning powder. As the base gets ignited and pressure builds it pushes the entire stack against the shoulder increasing pressure and thus decreasing burn time. If all goes well the entire column is ignited by the time the last powder hits the end of the neck. And the major push on the bullet is just after it leaves the neck. With larger cases I rarely bump up much in powder speed. As in the .280 Rem to .280 Ackley I went from using 4350 to 4831. H1000 was too slow. Re-17 has come along and changed a lot of that. With the burn retardant properties it's actually affected how you want to attain speed, not just keep from accidentally blowing up your firearm...and you.
Re: 260 rem vs 260 ackley
tag, looking at doing a build in two weeks. 260 or 260 AI, haven't decided yet.
tag, looking at doing a build in two weeks. 260 or 260 AI, haven't decided yet.
Re: 260 rem vs 260 ackley
dies cost a shit ton..
brass is a pain
for what?.. a extra 50 to 90 FPS?... not worth it...
dies cost a shit ton..
brass is a pain
for what?.. a extra 50 to 90 FPS?... not worth it...
Re: 260 rem vs 260 ackley
I love my 260 ackley and would do it again. Forming brass is not a pain. For the love of God, why do people think it is. Load a near max load for a standard 260 and go have fun. It will be insanely accurate during fire forming. Some guys fire form during Fclass matches, that is how accurate they can be. Then, take care of your brass as you normally would. If you want to save barrel big time, load down to standard 260 velocities and enjoy excellent barrel life and accuracy. Or be like me, ramp them up to 2920 and smack steel way out there with tremendous accuracy.
I love my 260 ackley and would do it again. Forming brass is not a pain. For the love of God, why do people think it is. Load a near max load for a standard 260 and go have fun. It will be insanely accurate during fire forming. Some guys fire form during Fclass matches, that is how accurate they can be. Then, take care of your brass as you normally would. If you want to save barrel big time, load down to standard 260 velocities and enjoy excellent barrel life and accuracy. Or be like me, ramp them up to 2920 and smack steel way out there with tremendous accuracy.
Re: 260 rem vs 260 ackley
260 standard is what i shoot
139 scenars at 2750... i used to shoot them at 2850
then at 1400 rnds accuracy went away..had it rechambered
cut 4 inches off
now i shoot slower...accuracy is back and im at 2800 rnds
the difference is speed is not as dramatic as miss reading the wind
jwv... the diff at 1000 is .2 mils of wind
i dont see any practical reason to do this
260 standard is what i shoot
139 scenars at 2750... i used to shoot them at 2850
then at 1400 rnds accuracy went away..had it rechambered
cut 4 inches off
now i shoot slower...accuracy is back and im at 2800 rnds
the difference is speed is not as dramatic as miss reading the wind
jwv... the diff at 1000 is .2 mils of wind
i dont see any practical reason to do this
Re: 260 rem vs 260 ackley
The 260 standard is less work and in my opinionfor 100 to 150 fps is not worth all the work invilved in prep.
The 260 standard is less work and in my opinionfor 100 to 150 fps is not worth all the work invilved in prep.
Re: 260 rem vs 260 ackley
I would go with the regular old 260 rem. Plenty to do anything you want and it will be much less work!!
I would go with the regular old 260 rem. Plenty to do anything you want and it will be much less work!!
Re: 260 rem vs 260 ackley
260rem because is it more widely available.
The extra velocity and case efficieny of the 260AI is too much trouble. Fire forming and donuts, neck turning etc...all the extra steps for brass prep...extra cost of dies etc....not worth it to me.
6.5 Creedmoor is a good option too. And if you really worth more velocity, then try the 6.5x284.
260rem because is it more widely available.
The extra velocity and case efficieny of the 260AI is too much trouble. Fire forming and donuts, neck turning etc...all the extra steps for brass prep...extra cost of dies etc....not worth it to me.
6.5 Creedmoor is a good option too. And if you really worth more velocity, then try the 6.5x284.
Re: 260 rem vs 260 ackley
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vkc</div><div class="ubbcode-body">260rem because is it more widely available.
The extra velocity and case efficieny of the 260AI is too much trouble. Fire forming and donuts, neck turning etc...all the extra steps for brass prep...extra cost of dies etc....not worth it to me.
6.5 Creedmoor is a good option too. And if you really worth more velocity, then try the 6.5x284. </div></div>
There is no extra case prep with the 260AI. Use 7-08 Win brass or Lapua 260. Just an extra step with sizing down, but sizing would have been necessary either way. You will not get donuts. And you will never have to trim your brass again after the initial time. To those saying that shooting the 140s in the 2900 range is not practical, then why do people use the 6.5x284 and shoot 2950 fps. You don't gain a lot but you still get that edge. The 6.5x284 is still one of the most popular Fclass cartridges, who wouldn't want 6.5x284 performance using less powder, cheaper brass and dies. Maybe I am just crazy but I am happy I skipped the standard 260 and sold all my 6.5x55 swede brass and dies.
Justin
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vkc</div><div class="ubbcode-body">260rem because is it more widely available.
The extra velocity and case efficieny of the 260AI is too much trouble. Fire forming and donuts, neck turning etc...all the extra steps for brass prep...extra cost of dies etc....not worth it to me.
6.5 Creedmoor is a good option too. And if you really worth more velocity, then try the 6.5x284. </div></div>
There is no extra case prep with the 260AI. Use 7-08 Win brass or Lapua 260. Just an extra step with sizing down, but sizing would have been necessary either way. You will not get donuts. And you will never have to trim your brass again after the initial time. To those saying that shooting the 140s in the 2900 range is not practical, then why do people use the 6.5x284 and shoot 2950 fps. You don't gain a lot but you still get that edge. The 6.5x284 is still one of the most popular Fclass cartridges, who wouldn't want 6.5x284 performance using less powder, cheaper brass and dies. Maybe I am just crazy but I am happy I skipped the standard 260 and sold all my 6.5x55 swede brass and dies.
Justin
Re: 260 rem vs 260 ackley
I've got my brand new 26" barrel at the gunsmith's being chambered in a no-turn tight(er) neck 6.5-08 AI.
All the bullets, brass, powder, and dies are in stand-by, ready to go.
This had better work!!!
B
I've got my brand new 26" barrel at the gunsmith's being chambered in a no-turn tight(er) neck 6.5-08 AI.
All the bullets, brass, powder, and dies are in stand-by, ready to go.
This had better work!!!
B
Re: 260 rem vs 260 ackley
My opinion about additional powder vs additional pressure is that it isn't an "either/or", it's a combination of the both.
IMHO, the additional pressure (and heat energy) contributes to throat checkering. The number and extremes of heat/pressure cycles governs the rate at which checkering progresses.
While aadditional powder accentuates the above issue, it also increases mechanical erosion caused by powder kernels impinging on the throat surface just downstream of the neck/shoulder junction. For this reason, I favor cartridge configurations that permit a longer case neck.
I suspect the additional case neck length constitutes a replaceable throat junction lining, and may favorably affect throat life.
An example might be the neck length difference between the .222 Rem and the .223 Rem. The .223 Rem represents to me all those things (additional powder, less neck length) going the wrong way vs the .222 Rem.
Greg
My opinion about additional powder vs additional pressure is that it isn't an "either/or", it's a combination of the both.
IMHO, the additional pressure (and heat energy) contributes to throat checkering. The number and extremes of heat/pressure cycles governs the rate at which checkering progresses.
While aadditional powder accentuates the above issue, it also increases mechanical erosion caused by powder kernels impinging on the throat surface just downstream of the neck/shoulder junction. For this reason, I favor cartridge configurations that permit a longer case neck.
I suspect the additional case neck length constitutes a replaceable throat junction lining, and may favorably affect throat life.
An example might be the neck length difference between the .222 Rem and the .223 Rem. The .223 Rem represents to me all those things (additional powder, less neck length) going the wrong way vs the .222 Rem.
Greg
