Ugh. No, this "trans-sonic" thing is often grossly overstated. It's effects are negligible and overshadowed by other factors having to do with ammo quality. Supersonic rimfire rounds are more susceptible to wind drift, but they are not de-stabilized by the transition to any noticeable degree. The exceeding majority of supersonic .22LR ammo available is cheap, bulk producing garbage with little in the way of quality control. Cartridge defects and inconsistent powder/primer charges are the reasons why their accuracy sucks, not the trans-sonic zone.
Rimfire PRS ammo choice
- Thread starter britguy
- Start date
Ugh. No, this "trans-sonic" thing is often grossly overstated. It's effects are negligible and overshadowed by other factors having to do with ammo quality. Supersonic rimfire rounds are more susceptible to wind drift, but they are not de-stabilized by the transition to any noticeable degree. The exceeding majority of supersonic .22LR ammo available is cheap, bulk producing garbage with little in the way of quality control. Cartridge defects and inconsistent powder/primer charges are the reasons why their accuracy sucks, not the trans-sonic zone.
- Location
- West Quebec
I'll have to check Gunworks ..thanks
Since the question was raised, this post is to consider the question of the effects of transonic turbulence on .22LR bullets. It is not to foment argument. It is not to cast aspersions nor to make prescriptions.
While shooters of powerful PCP air rifles may be familiar with the adverse effects of transonic turbulence on their pellets, it seems that transonic turbulence is also a concern for those doing extreme long range shooting with centerfire rifles.
According to "Transonic Effects on Bullet Stability & BC" by the knowledgeable student of ballistics Bryan Litz,
What happens when the bullet slows to transonic speed, i.e. when the bullet slows to about 1340 feet per second? It is getting close to the speed of sound, close to the sound barrier. That is a bad place to fly for anything. In particular, for bullets that are spin-stabilized, what the sound barrier does to a bullet (as it flies near Mach 1) is that it has a destabilizing effect. The center of pressure moves forward, and the over-turning moment on the bullet gets greater. You must then ask: “Is your bullet going to have enough gyroscopic stability to overcome the increasing dynamic instability that’s experienced at transonic speed?”
Some bullets do this better than others. Typically bullets that are shorter and have shallow boat-tail angles will track better through the transonic range. On the contrary, bullets that are longer… can experience a greater range of pitching and yawing in the transonic range that will depress their ballistic coefficients at that speed to greater or lesser extents depending on the exact conditions of the day. That makes it very hard to predict your trajectory for bullets like that through that speed range.
(See h t t p ://www.appliedballisticsllc.com/Articles/ABDOC2.6%20-%20Transonic%20Effects%20on%20Bullet%20Stability%20&%20BC.pdf )
Further details are offered in PrecisionRifleBlog.com
(See h t t p s://precisionrifleblog.com/2018/09/17/extreme-long-range-tips-ballistics-time-of-flight/ )
If air rifle pellets suffer from transonic turbulence and centerfire bullets experience transonic turbulence during extreme long range shooting (it takes a considerable distance before such projectiles slow down enough to enter the transonic zone, while pellets slow down very quickly), is there any reason to believe that the high velocity or hyper velocity .22LR bullet is immune from the problem?
Perhaps it is not a serious issue for .22LR ammo that has an MV greater than the speed of sound. I don't have first hand experience as I don't use such ammo with any frequency. At the same time, it might not be unreasonable to believe that the transonic effects that .22LR high or hyper velocity ammo experiences doesn't do a thing to help accuracy but rather has a deleterious effect instead.
What is clear is that .22LR standard velocity ammo, typically around 1075 - 1080 fps, never exceeds the speed of sound and so never enters the transonic zone as it slows down during flight. To be sure .22 LR SV match ammo is made to a much better quality level than most if not all .22LR HV ammo and that gives it a big leg up on the latter when it comes to .22LR accuracy, whether it's at 50 yards, 100, or more.
While shooters of powerful PCP air rifles may be familiar with the adverse effects of transonic turbulence on their pellets, it seems that transonic turbulence is also a concern for those doing extreme long range shooting with centerfire rifles.
According to "Transonic Effects on Bullet Stability & BC" by the knowledgeable student of ballistics Bryan Litz,
What happens when the bullet slows to transonic speed, i.e. when the bullet slows to about 1340 feet per second? It is getting close to the speed of sound, close to the sound barrier. That is a bad place to fly for anything. In particular, for bullets that are spin-stabilized, what the sound barrier does to a bullet (as it flies near Mach 1) is that it has a destabilizing effect. The center of pressure moves forward, and the over-turning moment on the bullet gets greater. You must then ask: “Is your bullet going to have enough gyroscopic stability to overcome the increasing dynamic instability that’s experienced at transonic speed?”
Some bullets do this better than others. Typically bullets that are shorter and have shallow boat-tail angles will track better through the transonic range. On the contrary, bullets that are longer… can experience a greater range of pitching and yawing in the transonic range that will depress their ballistic coefficients at that speed to greater or lesser extents depending on the exact conditions of the day. That makes it very hard to predict your trajectory for bullets like that through that speed range.
(See h t t p ://www.appliedballisticsllc.com/Articles/ABDOC2.6%20-%20Transonic%20Effects%20on%20Bullet%20Stability%20&%20BC.pdf )
Further details are offered in PrecisionRifleBlog.com
(See h t t p s://precisionrifleblog.com/2018/09/17/extreme-long-range-tips-ballistics-time-of-flight/ )
If air rifle pellets suffer from transonic turbulence and centerfire bullets experience transonic turbulence during extreme long range shooting (it takes a considerable distance before such projectiles slow down enough to enter the transonic zone, while pellets slow down very quickly), is there any reason to believe that the high velocity or hyper velocity .22LR bullet is immune from the problem?
Perhaps it is not a serious issue for .22LR ammo that has an MV greater than the speed of sound. I don't have first hand experience as I don't use such ammo with any frequency. At the same time, it might not be unreasonable to believe that the transonic effects that .22LR high or hyper velocity ammo experiences doesn't do a thing to help accuracy but rather has a deleterious effect instead.
What is clear is that .22LR standard velocity ammo, typically around 1075 - 1080 fps, never exceeds the speed of sound and so never enters the transonic zone as it slows down during flight. To be sure .22 LR SV match ammo is made to a much better quality level than most if not all .22LR HV ammo and that gives it a big leg up on the latter when it comes to .22LR accuracy, whether it's at 50 yards, 100, or more.
I have seen through my scope as I watch bullets in the air when supersonic ammo dart about in an unpredictable manner as it passes through the transonic zone.
And sub sonic ammo does not do this.
I would say that if you cant shoot the difference, then you would not notice, but if you have a reasonably accurate rifle and shoot targets at 50, 100, 150 and 200 plus and compare group sizes, the groups will open in a fairly linear pattern relative to the distance with sub sonic ammo but not with supersonic.
Again, if you cant shoot the difference, you wont notice, but if you can shoot about 1 moa at 100 yards then you most certainly will see a difference.
And sub sonic ammo does not do this.
I would say that if you cant shoot the difference, then you would not notice, but if you have a reasonably accurate rifle and shoot targets at 50, 100, 150 and 200 plus and compare group sizes, the groups will open in a fairly linear pattern relative to the distance with sub sonic ammo but not with supersonic.
Again, if you cant shoot the difference, you wont notice, but if you can shoot about 1 moa at 100 yards then you most certainly will see a difference.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Since the question was raised, this post is to consider the question of the effects of transonic turbulence on .22LR bullets. It is not to foment argument. It is not to cast aspersions nor to make prescriptions.
While shooters of powerful PCP air rifles may be familiar with the adverse effects of transonic turbulence on their pellets, it seems that transonic turbulence is also a concern for those doing extreme long range shooting with centerfire rifles.
According to "Transonic Effects on Bullet Stability & BC" by the knowledgeable student of ballistics Bryan Litz,
What happens when the bullet slows to transonic speed, i.e. when the bullet slows to about 1340 feet per second? It is getting close to the speed of sound, close to the sound barrier. That is a bad place to fly for anything. In particular, for bullets that are spin-stabilized, what the sound barrier does to a bullet (as it flies near Mach 1) is that it has a destabilizing effect. The center of pressure moves forward, and the over-turning moment on the bullet gets greater. You must then ask: “Is your bullet going to have enough gyroscopic stability to overcome the increasing dynamic instability that’s experienced at transonic speed?”
Some bullets do this better than others. Typically bullets that are shorter and have shallow boat-tail angles will track better through the transonic range. On the contrary, bullets that are longer… can experience a greater range of pitching and yawing in the transonic range that will depress their ballistic coefficients at that speed to greater or lesser extents depending on the exact conditions of the day. That makes it very hard to predict your trajectory for bullets like that through that speed range.
(See h t t p ://www.appliedballisticsllc.com/Articles/ABDOC2.6%20-%20Transonic%20Effects%20on%20Bullet%20Stability%20&%20BC.pdf )
Further details are offered in PrecisionRifleBlog.com
(See h t t p s://precisionrifleblog.com/2018/09/17/extreme-long-range-tips-ballistics-time-of-flight/ )
If air rifle pellets suffer from transonic turbulence and centerfire bullets experience transonic turbulence during extreme long range shooting (it takes a considerable distance before such projectiles slow down enough to enter the transonic zone, while pellets slow down very quickly), is there any reason to believe that the high velocity or hyper velocity .22LR bullet is immune from the problem?
Perhaps it is not a serious issue for .22LR ammo that has an MV greater than the speed of sound. I don't have first hand experience as I don't use such ammo with any frequency. At the same time, it might not be unreasonable to believe that the transonic effects that .22LR high or hyper velocity ammo experiences doesn't do a thing to help accuracy but rather has a deleterious effect instead.
What is clear is that .22LR standard velocity ammo, typically around 1075 - 1080 fps, never exceeds the speed of sound and so never enters the transonic zone as it slows down during flight. To be sure .22 LR SV match ammo is made to a much better quality level than most if not all .22LR HV ammo and that gives it a big leg up on the latter when it comes to .22LR accuracy, whether it's at 50 yards, 100, or more.
Fantastic info and something MANY in the precision game do not understand. yes, rimfire bullets can be affected greatly by a variety of things as distances stretch out.... not the most ballistically blessed shapes.
These issues translate into the centerfire world but that is for another topic.
Me, I do not want my rimfire ammo to 'pop' over 1100fps... With my new set up, accurate fire at 300 to 400yds is possible. Working on new ways to reach out further... and this is not the spray and pray we typically see.
I continue to be super impressed by what is possible with these little cartridges.
Jerry
Interesting that the sharpness of the rifling has an effect on stability in the transonic zone.
David Tubbs recommended polygonal rifling to me years ago and said that's all he shoots now... at that time anyways.
I wonder if he was aware of this at the time.
David Tubbs recommended polygonal rifling to me years ago and said that's all he shoots now... at that time anyways.
I wonder if he was aware of this at the time.
