Backspin to extend range of round ball projectiles in air rifle barrels

[UnderPressure]

I think for an external magnet to "see"  a steel BB inside the barrel to apply the rotational friction, the barrel needs to be non-magnetic, and thin walled.  So, steel is out; unless you somehow magnetize only the upper "strip" of the barrel.

Here is the choke for the Air Venturi Wingshot II and Double shot:

https://www.pyramydair.com/product/air-venturi-12-2mm-choke?a=6698

It screws onto external threads at the muzzle end.

Maybe with enough testing Air Venturi could design a plastic extension (with a place for magnets) that attaches to those same external threads as a method to impart back spin? This would also serve as a thread protector. (Right now there is no thread protector for the Wingshot or Double. In order to shoot arrows or round balls a person needs to unscrew the choke and use the gun with exposed threads---> ).

[Chris USA]

I played around with putting small, very strong magnets on the 499 barrel to induce back spin. It seemed to help,.. most of the time. The 499 trigger is not the best.

You mention "It seemed to help.... most of the time. The (Daisy) 499 trigger not being the best."

Overall, did you notice improving accuracy via the method of using a magnet to induce backspin?

Overall,... yes. But not by much. I shoot at 24' indoors. Beside the trigger,... any magnet forces you to use a push rod (1/8" wood dowel) to push the bb down to the start point (no just dropping it in). That got old pretty quick.

I did do a Red Ryder spring mod. though and it raised the fps 150. And, it is still as accurate if not more so. No less for sure. Cocking went from 5 to 10#, best I could measure and trigger weight did not change. Raised POI 2" at 41'. Worth doing in my book.

[UnderPressure]

I played around with putting small, very strong magnets on the 499 barrel to induce back spin. It seemed to help,.. most of the time. The 499 trigger is not the best.

You mention "It seemed to help.... most of the time. The (Daisy) 499 trigger not being the best."

Overall, did you notice improving accuracy via the method of using a magnet to induce backspin?

Overall,... yes. But not by much. I shoot at 24' indoors. Beside the trigger,... any magnet forces you to use a push rod (1/8" wood dowel) to push the bb down to the start point (no just dropping it in). That got old pretty quick.

I did do a Red Ryder spring mod. though and it raised the fps 150. And, it is still as accurate if not more so. No less for sure. Cocking went from 5 to 10#, best I could measure and trigger weight did not change. Raised POI 2" at 41'. Worth doing in my book.

I'm glad to hear it became overall more accurate.

I wonder if with a plastic muzzle extension (containing magnets) you could get more backspin?

[UnderPressure]

Be VERY careful about ricochets with metal balls at low velocities.... They don't seem bad at 500 fps, but at 300-350 fps can end up coming back at you with significant energy remaining.... depending on the target....

If we apply backspin to the steel BB wouldn't the chances of it coming straight back be decreased if it hit a perpendicular surface?

For example, in basketball if a person shoots with backspin and hits the backboard the ball will deaden (to some extent) and have an increased chance of dropping in the basket.....rather than energetically bouncing off the backboard (as when no backspin is applied to the ball).

Then there is also the idea that if backspin is sufficient to increase range that also reduces the chance of BB coming straight back at the shooter.

[UnderPressure]

Be VERY careful about ricochets with metal balls at low velocities.... They don't seem bad at 500 fps, but at 300-350 fps can end up coming back at you with significant energy remaining.... depending on the target....

If we apply backspin to the steel BB wouldn't the chances of it coming straight back be decreased if it hit a perpendicular surface?

For example, in basketball if a person shoots with backspin and hits the backboard the ball will deaden (to some extent) and have an increased chance of dropping in the basket.....rather than energetically bouncing off the backboard (as when no backspin is applied to the ball).

Then there is also the idea that if backspin is sufficient to increase range that also reduces the chance of BB coming straight back at the shooter.

Here is a link discussing backspin and it's effect on ricochet off the backboard in basketball:

https://blogs.umass.edu/p139and/2012/12/13/physics-of-basketball/

When a shooter releases a basketball the distance it travels occurs as a direct product of the amount of force that he/she applied.  The further away from the basket the shooter is, the more force they will be required to put on a shot if they want to get it in the hoop.  The spin a shooter puts on the ball occurs as a result of their release.  A good jump shot typically has a good amount of backspin so that if the ball were to ricochet off the backboard it would come off at a downward angle into the hoop. 

[Nomadic Pirate]

There is a reason backspin is huge in airsoft, .......but it's not even considered in Big bore roundball shooters

Trying to reinvent the wheel at times it's an exercise in futility.

[UnderPressure]

There is a reason backspin is huge in airsoft, .......but it's not even considered in Big bore roundball shooters

Trying to reinvent the wheel at times it's an exercise in futility.

The higher the velocity the gets the greater the amount of backspin needed to get aerodynamic lift:

http://mackila.com/airsoft/atp/03-a-01.htm

Figure III-A-10 shows how velocity affects trajectory when hop-up is applied.  At lower linear speeds, V/U is high and results in a drastic, skyward arc in the pellet's trajectory.  At higher linear speeds, the force of lift is insufficient as V/U is too low.  It should be noted that, for equal hop-up settings, a higher muzzle velocity will result in higher spin rates (i.e., a hop-up setting that generates 95,000 rpm when a 0.20g pellet passes through at 300 fps might generate 125,000 rpm if the same pellet passed through at 400 fps), meaning that upgrading your gun will alter the trajectory, however it may not be as drastic as depicted below due to my use of consistent spin rates.  I should note that a 200 fps shot with an initial spin of 95,000 rpm would have a very high V/U, and the trajectory depicted below for the 200 fps shot is probably impossible, as it would be very difficult to generate such high spin from a relatively low-energy shot.

And then there is the idea of heaviest largest caliber lead round balls (which could use the aerodynamic lift the most) obturating under blackpowder making them not so round.

The higher the pressure the greater the obturation and the lower the degree of roundness.......which means rifling becomes what is needed rather than smoothbore and backspin.

But airguns use much much lower pressures and velocity......

[darkcharisma]

There is a reason backspin is huge in airsoft, .......but it's not even considered in Big bore roundball shooters

Trying to reinvent the wheel at times it's an exercise in futility.

hes not trying to reinvent the wheels. i bet the likeliness of him trying to pursue it in practice is slim to none. this is strictly discusion and will likely continue to be so.

up to this point. no one has tried backspinning a heavy Lead ball. maybe you could enlighten us all with solid data on LEAD balls, rather than all the airsoft and bb related articles you read and cited? all theory, no support on actual Lead balls backspinning at 25-50-100yards.

Not trying to be a party popper but i just dont see it ever happenning or have good outcome. thats my prediction. why must one fixate on lead balls with negative potential when other projectiles outperform?

i hope this will go somewhere rather than discussion only. no data yet on leadballs, all BBs and airsoft..........whose articles dont apply , IMHO.

[Nomadic Pirate]

There is a reason backspin is huge in airsoft, .......but it's not even considered in Big bore roundball shooters

Trying to reinvent the wheel at times it's an exercise in futility.

hes not trying to reinvent the wheels. i bet the likeliness of him trying to pursue it in practice is slim to none. this is strictly discusion and will likely continue to be so.

up to this point. no one has tried backspinning a heavy Lead ball. maybe you could enlighten us all with solid data on LEAD balls, rather than all the airsoft and bb related articles you read and cited? all theory, no support on actual Lead balls backspinning at 25-50-100yards.

Not trying to be a party popper but i just dont see it ever happenning or have good outcome. thats my prediction. why must one fixate on lead balls with negative potential when other projectiles outperform?

i hope this will go somewhere rather than discussion only. no data yet on leadballs, all BBs and airsoft..........whose articles dont apply , IMHO.

Yeah at some point just bringing up articles from airsoft and bb shooter just don't cut it,

time to create some data, all this theoretical stuff it's good for nothing applied to big bore roundballs

[Chris USA]

I played around with putting small, very strong magnets on the 499 barrel to induce back spin. It seemed to help,.. most of the time. The 499 trigger is not the best.

You mention "It seemed to help.... most of the time. The (Daisy) 499 trigger not being the best."

Overall, did you notice improving accuracy via the method of using a magnet to induce backspin?

I replied once,... I guess it did not take.   

Yes, overall,.. it did. But not by a whole lot and not always consistently.

I did do a Red Ryder spring mod.. It raised the fps 150.  I shoot at 24' indoors. At 41', it raised the POI 2". Cocking effort went from 5# to 10# (best I could measure) and no increase in trigger pull. WELL worth it in my opinion. Accuracy is better I do believe. It is for sure no worse.

[UnderPressure]

There is a reason backspin is huge in airsoft, .......but it's not even considered in Big bore roundball shooters

Trying to reinvent the wheel at times it's an exercise in futility.

hes not trying to reinvent the wheels. i bet the likeliness of him trying to pursue it in practice is slim to none. this is strictly discusion and will likely continue to be so.

up to this point. no one has tried backspinning a heavy Lead ball. maybe you could enlighten us all with solid data on LEAD balls, rather than all the airsoft and bb related articles you read and cited? all theory, no support on actual Lead balls backspinning at 25-50-100yards.

Not trying to be a party popper but i just dont see it ever happenning or have good outcome. thats my prediction. why must one fixate on lead balls with negative potential when other projectiles outperform?

i hope this will go somewhere rather than discussion only. no data yet on leadballs, all BBs and airsoft..........whose articles dont apply , IMHO.

Two things:

1. Big Bore Air Rifles are for all practical reasons a very recent thing---> https://www.pyramydair.com/blog/2011/07/sam-yang-dragon-claw-50-caliber-big-bore-air-rifle-part-1/ (Read History of big bore air guns in the link)
2. Almost all these big bore airguns are rifled!! (I order to even think of this doing this with lead round ball a person needs a smoothbore.)

[Nomadic Pirate]

Big Bore Air rifles have been around a long time, look at the Old Shin Sung Dragon Slayer .50 and Ultra .357 and Roundballs where the ticket back then
DAQ big bores have been around a long time too.

Sam Yang just came out with the Wingshot smoothbore as a shotgun style gun


If you wanna shoot roundballs get a rifled Big bore

...or just buy a Wingshot and start experimenting with this backspin thing, all this articles and examples from airsofts will take you nowhere

Even better get a Wingshot and a Dragon claw and compare side by side backsping and rifled.

[darkcharisma]

I dont care about big bores. i did not say big bores. i said "Heavy Lead Balls".

you can do it in .22 or .25. i bet you will not be able to hit anything at 50 yards compared to pellets.

are we in a shortage for pellets? if you look at history of ammunition, you know we dont use round balls...ever wonder why?

[UnderPressure]

Big Bore Air rifles have been around a long time, look at the Old Shin Sung Dragon Slayer .50 and Ultra .357 and Roundballs where the ticket back then
DAQ big bores have been around a long time too.

Notice I used the words "Big Bore Air Rifles are for all practical reasons a very recent thing".

If you read the information in the link I provided in reply #30 it explains why.

[darkcharisma]

"Gary’s guns eventually were (and still are) very accurate, after he learned how to rifle barrels, but the early smoothbores I tested back in 1998 were barely able to keep their balls on a 4’x4′ cardboard box at 50 yards."

thats a quote from the article. are you convinced that lead balls dont work in smooth bore now? thats one od tour own articles you provided, did you read that or no? how did you miss that?

[UnderPressure]

thats a quote from the article. are you convinced that lead balls dont work in smooth bore now?

No.

It does nothing to convince me lead balls can't be accurate (enough) in a smooth bore. (That example is actually worse accuracy than a paintball gun which shoots a super low BC super low velocity not so round projectile with a seam across its diameter). It only proves to me that big bores were not practical in the 1990s.

As I wrote in reply #30 "Big Bore Air Rifles are for all practical reasons a very recent thing."

[UnderPressure]

For anyone wanting to experiment with either lead balls or steel balls and backspin I think the following information is extremely important:

http://mackila.com/airsoft/atp/03-a-01.htm

Figure III-A-07 shows the effects of hop-up upon a 0.30g pellet fired at 407 fps.  Again, we see the Reverse Magnus Effect cause degraded performance if hop-up is engaged yet not sufficiently high to generate a high V/U.  It should also be noted that the plots are exaggerated along the y-axis -- while the degraded trajectory of shots fired with low hop-up are obvious on the plot, it would not be nearly so conspicuous in real observation.  At 135,000 rpm, we see a relatively flat trajectory, while at 150,000 rpm we see a trajectory showing a greater arc above the aim point.  While the 150,000 rpm shot will provide greater range, the 135,000 rpm would be more desirable as it would provide a flatter trajectory.  Again, the axis is exaggerated -- the arc would not seem nearly so obvious in reality.

Notice in the above example having some backspin does not mean the projectile trajectory will flatten.

In fact, as one can see 0 rpm (i.e. no backspin) has a better trajectory than 40,000 rpm backspin, 80,000 rpm backspin and 120,000 rpm backspin.

It is only until 135,000 rpm backspin that the trajectory is flatter.

Here is another example showing trajectory can worsen with backspin until a critical level of backspin is reached:

Figure III-A-06 shows the effects of hop-up upon a pellet.  Notice that at 0 revolutions per minute (rpm) the pellet experiences a normal parabolic trajectory.  At 36,000 rpm, V/U is low enough such that lift is negative due the Reverse Magnus Effect; since the force is negative (i.e., downward) it aids gravity in causing the pellet to fall.  At 72,000 rpm, the Reverse Magnus Effect is higher still, causing a sharply downward trajectory.  At around 100,000 rpm, the Magnus Effect begins to take effect causing positive lift, providing a trajectory closer to that of a BB fired without spin.  At 115,000 rpm, the trajectory appears flat due to the effects of gravity being marginally negated due to the Magnus Force, while a higher rpm will cause the BB to arc skyward.

[Nomadic Pirate]

What does  "Big Bore Air Rifles are for all practical reasons a very recent thing." even mean.

"and recent thing", .....how recent is recent ?

[Nomadic Pirate]

I think for an external magnet to "see"  a steel BB inside the barrel to apply the rotational friction, the barrel needs to be non-magnetic, and thin walled.  So, steel is out; unless you somehow magnetize only the upper "strip" of the barrel.

Maybe with enough testing Air Venturi could design a plastic extension (with a place for magnets) that attaches to those same external threads as a method to impart back spin? This would also serve as a thread protector.

Air Venturi will not spend a dime in R&D for this,....guess why ?

[darkcharisma]

Nope, i will not mod anything in my air rifles to shoot backspinning lead balls. why dont you do it?

and the article clearly stated smoothbore lead balls cannot hit 4x4 board at 50 yards. and that still not convince you? this was solid data provided on lead balls. yet you still try citing BB data.

dude...i give up.