quote:

Originally posted by 45 2.1:
Well Larry……. You really have no idea what this thread is about. It certainly isn’t about you or your precious theory. It is about: AR 15 Fast Twist Cast Experience. Do you have one of these fast twist rifles… 7 twist or 8 twist? You bought the mold, but as of this date it seems to be unused according to what you have said. Until you have used the 22 Nato bullet in a fast twist rifle, anything you say is conjecture without proof. BTW, Joe and I have the original first run molds and have been the sole suppliers to others (which you were not included for very obvious reasons) of these 22 Nato bullets until the GB molds came in, some ten months after we had the first cut molds. We know what they will do. You, on the other hand do not. Until you do have some HV experience with it, anything negative you do have to say would be considered Trolling.

quote:

Originally posted by SmokinJ:
Larry, pre ban Colt HBAR 7 twist 5.56 NATO. Did Colt buy their barrels from Lothar Walther?

quote:

Originally posted by SmokinJ:
My 5.56 AR15 is a Colt pre ban HBAR with a 7 twist in 5.56. You said this . All are 20" barrels (sorry joe, no slick Lothar Walther barrels) . My Colt doesn't have a LW barrel.
You should know that from the first post. Did you read that post? Then why would you think all my rifles have LW barrels?

quote:

Originally posted by SmokinJ:
Oh, so you're saying 45 2.1 has LW barrels on all his guns?

quote:

Originally posted by SmokinJ:
Gosh Gibby, I'm confused. Why did you even mention LW barrels in any of your post??

quote:

Originally posted by SmokinJ:
Except for having tighter bore and groove dimensions, modern barrels are tough to get shoot cast at HV because of the extremely shallow groove depth. You've read what Madenshooter says about that. So the LW barrels are a hindrance in that respect.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by SmokinJ:
Except for having tighter bore and groove dimensions, modern barrels are tough to get shoot cast at HV because of the extremely shallow groove depth. You've read what Madenshooter says about that. So the LW barrels are a hindrance in that respect.

Yes, but HV with cast in shallow or multiple grooved barrels can be done.

Larry Gibson

quote:

Originally posted by Larry Gibson:
Joe

Just about everything has a limit. A car engine has a limit to rpm. Angle grinder discs, circular saw blades, etc., have a limit to rpm. No, they have a threshold where things start going bad when that threshold is exceeded. A blue printed and balance car engine runs at higher RPM than the standard engine, Grinders, saw blades also can be spun to a higher RPM if they are finely balanced. Even unbalanced car tires can spin smoothly to a certain speed/RPM threshold before they start wobbling and bouncing yet balance them and they will run to a much higher speed/RPM. The better balanced, the higher the RPM threshold gets pushed to with your own examples. The "blue printing" and "balancing" mentioned are akin to how we cast, size, load, fit and accllerate cast bullets. The "spinning" or RPM is akin to what happens to the bullet in flight out side the barrel. hat's where the centrafugal force acts on the bullets imbalance. Have enough imbalance at a high enough RPM and it exceeds the RPM threshold. You are wrong on many points in that paragraph. First grinder discss, saw blades, car flywheels, etc., are balanced. Balanced is balanced. What makes them reach their limit is the material strength. Ever hears of a scatter shield on a car bell housing? Blue printing a car engine means that every part is at the engineering measuring specifications. Like pistong clearance, bearing clearance, ring clearance, just to name a few. The engine runs better if all those are correct. It's actually different stronger parts that let an engine run to higher rpm. For example bearings. You don't have the same bearings in a family engine that is in a racing engine.

Gibby your rpm limit is vague. When you first came out with the threshold there wasn't any pushing the limit up. Once again joe, the RPM threshold is not nor has it ever been a "limit". It is a threshold that can be moved up or down. I have always said that. For the common cast bullets pushed with "regular" cast bullet loads the threshold generally falls in the 120-140,000 RPM range. Again, we can lower or raise that figure. But it answers the question we most often see; why does my 311291 (or similar cast bullet) lose accuracy above 1900 fps out of my '06 when I load it with 2400, 4759, 3031, 4985, etc? The answer is the bullet is exceeding the RPM threshold (that point at which the centrafugal force adversely affects accuracy) for the componants he is using in the 10" twist of his '06. Yes we can tell him how to raise or even lower that RPM threshold but telling him that does not answer the question of why te accuracy oes south at 1900+ fps. The answer to his question is; the RPM threshold is exceeded at 1900+ fps with your componants. As I said you came up with the "limit" as we kept shooting more and more rifles out of your threashold. It's bad you don't know the reason those powders you named won't shoot higher rpm. I'll tell you...it's because they are much faster then the slow powders and they slam the fragile cast alloy bullet we use and damage it. Damage it you unbalance it. It also may, because of it's abrupt pressure speed, start it into the bore crooked. They also create different barrel harmonics.

What there was, was "Joe has an exception rifle". That's what you use to say to me, remember that? Today you have at least accepted we have pushed quite a few rifles out of your original threshold boundaries. Yes, I did say that but you are taking it out of context. You can raise, lower or just accept the RPM threshold in any rifle/cartridge with a twist that is fast enough. I do not think there are "exceptional rifles" in that context. We can shoot a correct cast bullet at HV/RPM with rack grade commercial, misurp and custom made barrels/firearms. The RPM threshold will probably be different for the same cartridge componants as the barrel quality is different is all. I don't believe it was out of context. You didn't have an answer to why me and my rifles could do it.

I'm trying to get you to except that over spinning a bullet of any material doesn't destroy it's accuracy super bad. I never siad over spinning "destroys" accuracy "super bad". That's your words you are trying to convince everyone I said and mean. It's simply not true. Yes it is true. For the distances that most of us shoot a higher rpm isn't going to affect our accuracy enough for us to be discouraged by our groups.

You claim the high rpm affects the bullet in flight. Well if that was true how come very high velocity cartridges with fast twists shoot bullets to very long distances with accuracy?


They do, I never "claimed" they didn't. What I said was that over spinning a bullet (cast or jacketed) will cause some degree of inaccuracy. Let's take the .223/5/56 in ARs for example as it is the topic cartridge/rifle of this thread; The 8" twist is the accepted twist for best accuracy at 600 - 1000 yards with 70 - 85 gr bullets right (yes joe, that's what ALL the winning HP shooters use). Why don't they use a 7" twist barrel anymore? Because it was found the 8" twist did not over spin the bullets and gave better accuracy at longer range than the 7" twist. The same bullets also drifted less in the wind with the 8" twist because the BC was higher. Why don't they use the 9" twist? Because that twist does not adequately stabilize (underspins) the bullet and it is not as accurate as the 8" twist. That is with jacketed bullets of course. Every bullet, cast or jacketed, will have an optimal rotational speed (RPM) at which it will give the best accuray. Simple answer to that one Gibby. The heavier bullets that the 8 twist won't shoot really reduce the velocity. Added to that when loaded in the 5.56/223 in AR's they encroach on the already small powder capacity and limit velocity even more that is needed for 1000 yards. There is also increased pressure with the 7 twist, maybe more bullet damage, and more barrel wear.

It is easy to determine by actually measuring the BC of the same bullet at the same velocity out of different twists barrels. The BC measures the efficiency of the bullet in flight. Ergo the higher the BC the more efficient the bullet is in flight. If a bullet is overspun or underspun it will have a lower BC. I have actually completed this test numerous times with different bullets, jacketed and cast by measuring the BC (M43 Oehler with screens at the muzzle and at 100 yards) of the same bullet and the the same load from dfferent twists at the same velocity in the .223 with 7, 8, 9, 10, 12 and 14" twists and in the .308W with 10, 12 and 14" twists. Every bullet test preferred a certain twist rate which gave the highest BC. The others gave lower BCs because the bullet was over or under spun. That is a ballistic fact joe. Again insignificate for what we are doing.

Wouldn't this accuracy killing spin/spiral be exaggerated at the very long distances? It certainly is. That is the linier/non linear expansion of group tests I'm always telling you about. It is easy enough to tell if the bullet has exceeded the RPM threshold by comparing group sizes at short and longer ranges; if linear the bullet has not exceeded the RPM threshold. If the non linear the bullet hs exceeded the RPM threshold.

With jacketed bullets it's easy enough to tell comparing 10 shot group sizes between 100 and 300 (preferably 500 or 600 if weather conditions permit) yards. With cast bullets in rifles the group dispersion is easily determined with 10 shot groups at 100 and 200 yards. If the groups are non linear in dispersion the RPM threshold for that load/components has been exceeded. I can tell you our 300 to 350 yards groups with HV in fast twists (and slow twists) don't exhibit that.

Now I realize a rifle/cartridge/bullet combination that drills a hole a 100 yards will print larger groups the further you move the target out and that's because there are a lot of things combined together that cause that. It's not solely rpm alone. You are "realizing" correctly. Normal group dispersion under the RPM threshold will be linear in nature. However, read the explanation in the Hornady manuals and you will see that the inaccuracy of a bullet in flight, even the slightest of inaccuracy, is mostly influenced by unbalanced bullets and the adverse affect the RPM has on them. The highr the RPM the greater the adverse affect. It's why they strive to make match bullets especially as balanced as possible. It's why we shoot groups instead of one hole.

Thing about this, what would a bullet do in outer space..in a vacuum?


We aren't shooting bullets in space. What happens there doesn't matter on Earth, it's apples and oranges........ In space though it would be better for the bullet (and the football) if the was not rotational spin at all. The bullet nor the football have to spin in space as both would go on a straight line. They both, if lauched point forward would continue to fly point forward until some other force acted upon them.

Bullets and footballs need to be rotated on Earth to fly through the atmosphere. If spinning in space the adverse affects of the centrafugal force on any imbalance in either the bullet or the football would still have an affect on the flight. The centrafugal force would be "another force" acting upon either. Best we don't spin either in space........

An analogy that Gear told you was the football. Even when the football reached the end of it's trajectory and has lost most all it's spin, it still stays on course.

Very bad analogy joe, as explained above. Additionally, there would be no "trajectory" as we think of trajectory on Earth caused by gravity of the Earth and the football would not stop spinning as there would be nothing to slow the spin (Newtonian law of physics; an object in motion tends to stay in motion).

You and gear might want to study ballistics a little bit or at least consult with a "rocket scientist" before making such analogies. I am not a rocket scientist though I have discussed this topic with several and I have studied ballistics. It's always study or read something with you. You done very good running Dr B off the thread mentioned by both Gear and Bob in this thread. Now there's a highly educated man in the field you are discussing, but as always you know better. He knew better to just leave the thread. There is no changing your mind, showing you anything, or debating with you. You go on and on till you have thoroughly run everythone off. See anyone else participating in this thread now beside me, gear, bob, and you? Honest question HONEST QUESTION..and answer it Gibby...Do you realize that you do that?

Larry Gibson

quote:

Originally posted by SmokinJ:

quote:

Originally posted by Larry Gibson:
Joe

Just about everything has a limit. A car engine has a limit to rpm. Angle grinder discs, circular saw blades, etc., have a limit to rpm. No, they have a threshold where things start going bad when that threshold is exceeded. A blue printed and balance car engine runs at higher RPM than the standard engine, Grinders, saw blades also can be spun to a higher RPM if they are finely balanced. Even unbalanced car tires can spin smoothly to a certain speed/RPM threshold before they start wobbling and bouncing yet balance them and they will run to a much higher speed/RPM. The better balanced, the higher the RPM threshold gets pushed to with your own examples. The "blue printing" and "balancing" mentioned are akin to how we cast, size, load, fit and accllerate cast bullets. The "spinning" or RPM is akin to what happens to the bullet in flight out side the barrel. hat's where the centrafugal force acts on the bullets imbalance. Have enough imbalance at a high enough RPM and it exceeds the RPM threshold. You are wrong on many points in that paragraph. First grinder discss, saw blades, car flywheels, etc., are balanced. Balanced is balanced. What makes them reach their limit is the material strength. Ever hears of a scatter shield on a car bell housing? Blue printing a car engine means that every part is at the engineering measuring specifications. Like pistong clearance, bearing clearance, ring clearance, just to name a few. The engine runs better if all those are correct. It's actually different stronger parts that let an engine run to higher rpm. For example bearings. You don't have the same bearings in a family engine that is in a racing engine.

No joe, they are not balanced. Take them off a solidly mounted spindle and they wobble and vibrate. Run them to a higher RPM and they vibrate all over and wobble. Truely balance them and they won't. Then you could run them to a high enough RPM for disintegration. Everyone knows the blue printed engine runs to a higher RPM than thestandard engine because the parts are balanced, everyone except you 3 apparrently.

Gibby your rpm limit is vague. When you first came out with the threshold there wasn't any pushing the limit up. Once again joe, the RPM threshold is not nor has it ever been a "limit". It is a threshold that can be moved up or down. I have always said that. For the common cast bullets pushed with "regular" cast bullet loads the threshold generally falls in the 120-140,000 RPM range. Again, we can lower or raise that figure. But it answers the question we most often see; why does my 311291 (or similar cast bullet) lose accuracy above 1900 fps out of my '06 when I load it with 2400, 4759, 3031, 4985, etc? The answer is the bullet is exceeding the RPM threshold (that point at which the centrafugal force adversely affects accuracy) for the componants he is using in the 10" twist of his '06. Yes we can tell him how to raise or even lower that RPM threshold but telling him that does not answer the question of why te accuracy oes south at 1900+ fps. The answer to his question is; the RPM threshold is exceeded at 1900+ fps with your componants. As I said you came up with the "limit" as we kept shooting more and more rifles out of your threashold. It's bad you don't know the reason those powders you named won't shoot higher rpm. I'll tell you...it's because they are much faster then the slow powders and they slam the fragile cast alloy bullet we use and damage it. Damage it you unbalance it. It also may, because of it's abrupt pressure speed, start it into the bore crooked. They also create different barrel harmonics.

And when the "damaged" bullet is in flight what makes it inaccurate? You give the very reason why the RPM thresholdis there! At a certain level each of those powders damage the bullet so inaccuracy occurs in flight caused by the RPM threshold. Maybe if we called it; Joe's when the powder slams the bullet and unbalances it accuracy goes south theory. Maybe you'd understand it that way.......nah......you are just arguing for the sake of arguing............

What there was, was "Joe has an exception rifle". That's what you use to say to me, remember that? Today you have at least accepted we have pushed quite a few rifles out of your original threshold boundaries. Yes, I did say that but you are taking it out of context. You can raise, lower or just accept the RPM threshold in any rifle/cartridge with a twist that is fast enough. I do not think there are "exceptional rifles" in that context. We can shoot a correct cast bullet at HV/RPM with rack grade commercial, misurp and custom made barrels/firearms. The RPM threshold will probably be different for the same cartridge componants as the barrel quality is different is all. I don't believe it was out of context. You didn't have an answer to why me and my rifles could do it.

Well joe, not only you and rifles do it but so do mine, so do Von Gruffs and so do some others. It's not the rifles, it's knowing how to push the RPM threshold (whether or not you believe in it) upwards. Von Gruff is a perfect example. BTW; 45 2.1; A160 gr jacketed bullet can and is pushed to 2650 in modern actions chambered for the 7x57 cartridge when it is loaded to it's potential. Von Gruff definately pushed the RPM threshold up with his 160 gr cast but it is not to the potential of the cartridge in his rifle, very nice though.

I'm trying to get you to except that over spinning a bullet of any material doesn't destroy it's accuracy super bad. I never siad over spinning "destroys" accuracy "super bad". That's your words you are trying to convince everyone I said and mean. It's simply not true. Yes it is true. For the distances that most of us shoot a higher rpm isn't going to affect our accuracy enough for us to be discouraged by our groups.

Many find the PM threshold with cast bullets in the difference between 50 and 100 yards. Now if your groups are shot under 50 yards then you probably, and obviously aren't discouraged at all.

You claim the high rpm affects the bullet in flight. Well if that was true how come very high velocity cartridges with fast twists shoot bullets to very long distances with accuracy?


They do, I never "claimed" they didn't. What I said was that over spinning a bullet (cast or jacketed) will cause some degree of inaccuracy. Let's take the .223/5/56 in ARs for example as it is the topic cartridge/rifle of this thread; The 8" twist is the accepted twist for best accuracy at 600 - 1000 yards with 70 - 85 gr bullets right (yes joe, that's what ALL the winning HP shooters use). Why don't they use a 7" twist barrel anymore? Because it was found the 8" twist did not over spin the bullets and gave better accuracy at longer range than the 7" twist. The same bullets also drifted less in the wind with the 8" twist because the BC was higher. Why don't they use the 9" twist? Because that twist does not adequately stabilize (underspins) the bullet and it is not as accurate as the 8" twist. That is with jacketed bullets of course. Every bullet, cast or jacketed, will have an optimal rotational speed (RPM) at which it will give the best accuray. Simple answer to that one Gibby. The heavier bullets that the 8 twist won't shoot really reduce the velocity. Added to that when loaded in the 5.56/223 in AR's they encroach on the already small powder capacity and limit velocity even more that is needed for 1000 yards. There is also increased pressure with the 7 twist, maybe more bullet damage, and more barrel wear.

Obviously you don't shoot much HP nor really have read anything about it. The 80 & 85 gr match bullets are seated long because those ranges are shot slow fire. The cartridges are all single loaded into the rifle and do not have to feed from the magazine. Ergo they don't "encroach on the powder space". Besides, you once again ignore the point and context; with bullets of equal weight and velocity the heavier 75 - 85 gr match bullets have lower BCs with the 7 and 9" twists. They have the highest BCs with the 8" twist which is the reason everyone uses them. The top match shooters go through several barrels a year, they don't care about the insignificant difference in barrel life bbetween a 7 and 8" twist. They want accuracy and are smart enough to know where it is found, you aren't.

It is easy to determine by actually measuring the BC of the same bullet at the same velocity out of different twists barrels. The BC measures the efficiency of the bullet in flight. Ergo the higher the BC the more efficient the bullet is in flight. If a bullet is overspun or underspun it will have a lower BC. I have actually completed this test numerous times with different bullets, jacketed and cast by measuring the BC (M43 Oehler with screens at the muzzle and at 100 yards) of the same bullet and the the same load from dfferent twists at the same velocity in the .223 with 7, 8, 9, 10, 12 and 14" twists and in the .308W with 10, 12 and 14" twists. Every bullet test preferred a certain twist rate which gave the highest BC. The others gave lower BCs because the bullet was over or under spun. That is a ballistic fact joe. Again insignificate for what we are doing.

It's only "insignificant" to the 3 of you because it proves a point.

Wouldn't this accuracy killing spin/spiral be exaggerated at the very long distances? It certainly is. That is the linier/non linear expansion of group tests I'm always telling you about. It is easy enough to tell if the bullet has exceeded the RPM threshold by comparing group sizes at short and longer ranges; if linear the bullet has not exceeded the RPM threshold. If the non linear the bullet hs exceeded the RPM threshold.

With jacketed bullets it's easy enough to tell comparing 10 shot group sizes between 100 and 300 (preferably 500 or 600 if weather conditions permit) yards. With cast bullets in rifles the group dispersion is easily determined with 10 shot groups at 100 and 200 yards. If the groups are non linear in dispersion the RPM threshold for that load/components has been exceeded. I can tell you our 300 to 350 yards groups with HV in fast twists (and slow twists) don't exhibit that.

If they haven't exceeded the RPM threshold then they won't exibit non linear expansion. If they exceed the RPM threshold they will exhibit non linear expansion. That was well enough explained, obviously it escaped you?

Now I realize a rifle/cartridge/bullet combination that drills a hole a 100 yards will print larger groups the further you move the target out and that's because there are a lot of things combined together that cause that. It's not solely rpm alone. You are "realizing" correctly. Normal group dispersion under the RPM threshold will be linear in nature. However, read the explanation in the Hornady manuals and you will see that the inaccuracy of a bullet in flight, even the slightest of inaccuracy, is mostly influenced by unbalanced bullets and the adverse affect the RPM has on them. The highr the RPM the greater the adverse affect. It's why they strive to make match bullets especially as balanced as possible. It's why we shoot groups instead of one hole.

Thing about this, what would a bullet do in outer space..in a vacuum?


We aren't shooting bullets in space. What happens there doesn't matter on Earth, it's apples and oranges........ In space though it would be better for the bullet (and the football) if the was not rotational spin at all. The bullet nor the football have to spin in space as both would go on a straight line. They both, if lauched point forward would continue to fly point forward until some other force acted upon them.

Bullets and footballs need to be rotated on Earth to fly through the atmosphere. If spinning in space the adverse affects of the centrafugal force on any imbalance in either the bullet or the football would still have an affect on the flight. The centrafugal force would be "another force" acting upon either. Best we don't spin either in space........

An analogy that Gear told you was the football. Even when the football reached the end of it's trajectory and has lost most all it's spin, it still stays on course.

Very bad analogy joe, as explained above. Additionally, there would be no "trajectory" as we think of trajectory on Earth caused by gravity of the Earth and the football would not stop spinning as there would be nothing to slow the spin (Newtonian law of physics; an object in motion tends to stay in motion).

What, no counter point to the "in space....ina vacuum.....football analogy? ou always skip over the facts and just talk trash joe.

You and gear might want to study ballistics a little bit or at least consult with a "rocket scientist" before making such analogies. I am not a rocket scientist though I have discussed this topic with several and I have studied ballistics. It's always study or read something with you. You done very good running Dr B off the thread mentioned by both Gear and Bob in this thread. Now there's a highly educated man in the field you are discussing, but as always you know better. He knew better to just leave the thread. There is no changing your mind, showing you anything, or debating with you. You go on and on till you have thoroughly run everythone off. See anyone else participating in this thread now beside me, gear, bob, and you? Honest question HONEST QUESTION..and answer it Gibby...Do you realize that you do that?

Just trying to help you out joe. Just because you make stupid statements that are totally non factual isn't my fault, it's yours. The 3 of you should study ballistics a little, then perhaps you wouldn't come up with such stupid analogies. You might even understand how RPM affects accuracy while the bullet is in flight, who knows huh?I don't recall DrB posting in this thread nor did I mention him. Again you bring up something totally out of context. If DrB left another thread it was of his own violition. Last I recall he asked for a data graph that showed the RPM threshold. I provided it and didn't recieve a courtessy answer, he just didn't answer. Yes I and every one on the CBF and the 6.5 Grendel forums know why no one else is here......because you are here. You got banned from those forums for the same out of context and personal attacks you are making here. I'm betting lots of "lookers" here for the entertainment you 3 provide and the education and facts I provide.

BTW; do you really think you were kidding anyone with your "Gibby" come on routine? Didn't fool me and it didn't fool anyone else. You just asked the same old crap, made out of context statements and came up with stupid analogies. I answered with facts as always and you respond with trash. Same ole banned joe.........

How about you 3 "amigoe's" just discuss your BS and leave me out?

Larry Gibson

quote:

Originally posted by SmokinJ:
Gibby,

I answered your replies and your opinions to the questions I posed to you. If you'd debate without running people down that disagree with you we'd all get along better. The methology you use is not a good one. So I want to hear your replied to my disagreeing replies. The centrafugal force doesn't effect the bullet enough to get the groups we're getting. It's something else, that's what the thread was originally about. So you can see why I'm saying the threshold doesn't apply.

quote:

Originally posted by Geargnasher:
Joe, he doesn't see his pattern of self-serving thread destruction because topic is unrelated to agenda. This oblivion is a major characteristic of the illness. Damn annoying, too, when a person is trying to have a good discussion with the small handfull of people on the planet that can REALLY shoot cast boolits well outside of normally tight-lipped, competitive circles.

Gear

quote:

Originally posted by SmokinJ:
Larry, this was posted by you way back in 11/2007, just about 5 years ago:

The RPM threshold is area of velocity where the RPM created by the twist accentuates the defects in cast bullets creating excessive yaw, wobble and pitch of the bullet during flight. Defects in cast bullets are caused by imbalance due to out of round casting, other casting defects, or unwanted obturation during acceleration. Exactly where that threshold is depends on numerous things but those that mostly affect the threshold are; burning rate of powder, quality of cast bullet, design of cast bullet, alloy, fit of bullet to throat/leade and twist of the rifling. I've found over the years that with normal commercial moulds generally available (what most of us use), casting quality bullets of WWs or harder, with proper lube and fit to the throat when using medium to slow burning powders the threshold is in the 125-140,000 RPM range. If we are using the old '06 with a 10" twist and 311291 then the threshold translates to somewhere between 1735 fps and 1944 fps we will find the best accuracy when using 4895 or a slower burning powder.

Fact: Nowhere in that thread did you mention that there was a limit that could be pushed up or down. This is proof of what I'm saying that you have changed your tune to suit your arguments.

quote:

Originally posted by SmokinJ:
Bassackwards said this in that same thread back in 11/2007 and it is all about what my original post was about:

Internal cast ballistics dictates that a slug trying to accelerate is retarded by a twist rate angle in the bore. The more the rate angle is increased, (faster twist) the more that bullet will be held back and pressure will work on the base. In effect, it's the same as using a faster powder and we all know that slower powders do allow higher velocities. Also the more barrel time it will have exposed to that pressure. And the result will be the more barrel vibration and greater harmonics will take place. That is also why the lightest bullet per caliber achieves the highest RPM. And why softer bullets can be used with slower twist rates. And why larger case capacities lengthen pressure curves. Not because of stripping or bullet damage as most believe. So, when you lose cast accuracy is it because of external ballistics or internal ballistics at short ranges? Actually both. You work to mold to achieve perfection and your twist rate fights to destroy it. Pressure does the damage.

Fact: It's not the rpm of an undamaged balanced bullet that destroys it's useable accuracy, it's the fast twist in the barrel that ruins the bullet.

quote:

Originally posted by SmokinJ:
Larry I want you to know the above posts are not personal slams. They are debating your opinion of the threshold. When you reply please don't use such things as: you should read, have you read, you must be stupid, you just don't get it, I suggest, etc. I don't say any of those things to you.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by SmokinJ:
Bassackwards said this in that same thread back in 11/2007 and it is all about what my original post was about:

Internal cast ballistics dictates that a slug trying to accelerate is retarded by a twist rate angle in the bore. The more the rate angle is increased, (faster twist) the more that bullet will be held back and pressure will work on the base. In effect, it's the same as using a faster powder and we all know that slower powders do allow higher velocities. Also the more barrel time it will have exposed to that pressure. And the result will be the more barrel vibration and greater harmonics will take place. That is also why the lightest bullet per caliber achieves the highest RPM. And why softer bullets can be used with slower twist rates. And why larger case capacities lengthen pressure curves. Not because of stripping or bullet damage as most believe. So, when you lose cast accuracy is it because of external ballistics or internal ballistics at short ranges? Actually both. You work to mold to achieve perfection and your twist rate fights to destroy it. Pressure does the damage.

Fact: It's not the rpm of an undamaged balanced bullet that destroys it's useable accuracy, it's the fast twist in the barrel that ruins the bullet.

Bass was quite correct. However he does not say it isn't RPM, he asks the question; "So, when you lose cast accuracy is it because of external ballistics or internal ballistics at short ranges?" I'm sure my answer was something about the bullet is imbalanced during the internal ballistic but there is no "inaccuracy" as such there as the bullet is contained by the barrel. It is during the external ballistic phase that the inaccuracy occurs (if the cast bullet is exceeding the RPM threshold). It is RPM during the external ballisitc phase that is the cause of the inaccuracy.

If the bullet did not have to have spin/RPM to fly point on and there were no spin there would be no inaccuracy from the imbalances in the bullet caused during accelleration in the barrel or in the flight of the bullet during the external ballistic phase. This thing missing there is the spin/RPM ergo that is what causes the inaccuracy.

Your quote of Bass here is another example of your arcane ability to read into someone elses words what just isn't there.

Larry Gibson

quote:

Originally posted by SmokinJ:
There you go Larry calling me stupid. At any rate you didn't have a limit in your first posting of that.

Sometimes the shoe just fits joe. No I didn't have a "limit" in that post. You put the limit there joe, and I always have told you you're wrong.......there is not "limit". You continuing to say there is a "limit" and now using that post in an attempt to prove it only shows stupidity.

Now about Bass's statement, he was just being nice to you calling where the bullet becomes inaccurate the threshold.

Bass and I had a very good discussion and we completed a good test together. Bass, at first, had a hard time seperating the internal ballistic phase from the external ballistic phase just as the 3 of you are. I explained in my previous post the difference. The bullet is "inaccurate" in the barrel. "Inaccuracy" occurs during the external ballistic phase; the bullets flight outside the barrel.

What I'm trying to get you to see is that if the bullet is undamaged in firing, if it is balanced...rpm won't make the accuracy unusable until the bullet comes apart because we have exceeded the alloy's capabilities.

That is correct joe, if the bullet is undamaged and is balanced then the RPM won't make the accuracy "unuseable" if it exceeds the RPM threshold. Before the cast bullet comes apart it will deform and expand causing it to be imbalanced and inaccuracy will thenoccur before it comes apart. By asking these very questions and making these very statements it is obvious you understand the RPM threshold. Just get the "limit" part out of your thinking, understand that the RPM threshold can be movedup or down and it will all fall into place. Joe, you do understand it, your ego just won't let you say Larry is right.

That and why you have said repeatedly that you don't believe the accuracy I have gotten from the rifles that I reported.

First of all I never said you or anyone else couldn't get accuracy at a relative HV from any cartridge/rifle. The key is "relative HV" and what "accuracy" is. I do believe you get accuracy with HV out of your rifles, I get it out of mine also. What I question are many of your claims of consistent sub moa accuracy with almost every rifle from light weight commercial sporter, to milsurp to match grade rifles. Shooting such accuracy at normal velocity is difficult enough in them, Shooting submoa accuracy CONSISTENTY with the at HV is more difficult, especially with the sporter and milsurp rifles. It is the level of your accuracy claims that is questionable to me not the HV claims. Those claims are also very questionable to almost everyone else who has cast bullet shooting experience at HV.

Why are you incapable of saying "Wow Joe, that's pretty darn good, you've been able to get useable accuracy keep that bullet undamaged, balanced, and straight in the bore??

Joe, go back a few post of mine, the one after the sub moa target photo you posted. Doesn't my post strat off with "Wow"! And don't I then commend you and suggest you go compete in CBA matches as you clean their clocks?

Where in that post or the commendation I gave you and 45 2.1 in my own 6.5 thread on the CBF do you not find that I've not said "you've been able to get useable accuracy keep that bullet undamaged, balanced, and straight in the bore" in other words meaning the same thing. How many times have I said you've gotten useable accuracy at HV because you did not "beat the RPM threshold" but merely pushed it up by "keep(ing) that bullet undamaged, balanced, and straight in the bore". Once agan you are halucinating because your ego can not allow you to admit I'm right about the RPM threshld.

One thing further as far as shooting HV in fast twist rifles with useable accuracy. I have taught me zero in steps of loading for that. The man that has showed me the most is Bob. Also I've used fillers over 30 years ago, such as Kapok and Dacron. I'm the one on CB forum that preached never to tamp it down into a wad atop the powder charge, to spread it out from atop the powder to the base of the bullet. You have stepped in my footsteps for that since I'm gone.

All well and fine, I've been using fillers for 40+ years now so what's the big deal? It doesn't matter as we both were saying the same thing about dacron for the same time period. I'll be glad to give you all the credit for all of that as I don't need any credit. What has his got to do with the topic of this thread? Nothing, you are just feeding your ego so you won't have to admit Larry is right about the RPM threshold.

Larry Gibson