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All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: 45flint on September 06, 2018, 12:22:44 PM
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Here is my comparison of two pellets in my Sterioded Benjamin-Sheridan Silver Streak in 20 cal. The H&N 11.42 grain and the Benjamin 14.3 grain. The test showed basic physics works: energy is about equally but speed changes. If accuracy is the same what would you prefer? My assumption would be target shooter wants the speed and hunters want the heavier pellet? But energy is the same?
Pumps. FPS H&N 11.42. FPS Benjamin 14.3
3. 523. 471
4. 592. 528
5. 648. 583
6. 697. 12.32 FP. 610. 11.84 FP
7. 736. 13.74. 660. 13.84
8. 776. 15.27. 686. 14.95
10. 829. 735
12. 876. 19.46 FP. 794. 20.02 FP
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All things being equal I may be wrong but I would want a heavier pellet for hunting. More bullet mass means more kinetic energy and that equals to more damage.
But on the other hand a lighter pellet you will have more range I would think. So their you have it! I don’t have a clue. This will be interesting!!
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I don't think you would have more "range" with a lighter pellet. I think you would have a flatter trajectory out to some distance but then the lighter pellet would lose velocity (and energy) more rapidly than the heavier pellet. Seems "range" in this context would have to be defined as usable trajectory or required energy. That said, I don't hunt anymore and I prefer pellets on the lighter end of the scale for my lower powered springers and the more heavy for the higher powered PCP's. I really like flat trajectory.
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If the muzzle energy is the same, the lighter pellet will have less of that energy retained downrange than the heavier pellet, because it has a poorer BC and slows down faster.... That will also make it drift more in a crosswind.... However, the lighter pellet will have a flatter trajectory....
Other than having to deal with the greater drop downrange, the advantages lie with the heavier pellet, for target shooting or hunting.... However, eventually that increased drop makes it harder to hit your target....
Bob
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If you can get the benji pellets to equal the accuracy of the H&N ... use them !
Sadly i doubt that will be the case because not a .20 cal i own ( 5 in total ) shoot the benji's worth a da mn :P
Now get some JSB's and these other two will sit unused ;)
Accuracy TRUMPS energy or speed or trajectory.
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If you can get the benji pellets to equal the accuracy of the H&N ... use them !
Sadly i doubt that will be the case because not a .20 cal i own ( 5 in total ) shoot the benji's worth a da mn :P
Now get some JSB's and these other two will sit unused ;)
Accuracy TRUMPS energy or speed or trajectory.
Standard wisdom is the JSBs but my gun loves the H&Ns? Got to go back with the JSBs to make sure it wasn’t a fluke.
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I hear you on heavier weight down range but I wonder how much of that is Macho Hype. Seems to me Physics would carry down range and make them pretty equal? My gut is with the speed especially since my range in the backyard isn’t that great? Energy is Energy? At the mussel the squirrel gets the same killing power?
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I hear you on heavier weight down range but I wonder how much of that is Macho BS. Seems to me Physics would carry down range and make them pretty equal? My gut is with the speed especially since my range in the backyard isn’t that great? Energy is Energy?
In the .20's, weight differences between light and heavy is so nominal it's really a secondary consideration. hardness of the lead, nose shape relate to penetration, and cost to how much lead you plan on sending down range.
Personally in hunting small critters prefer SOFT lead that easily deforms upon impact, is slipperier within the bore and generally more velocity stable over harder lead.
Understand we're not talking Match Grade gun or accuracy here out of a brass barrel sheridan ... so don't overthink this and keep it at basic best accuracy and be done with it.
Practicing your shooting technique will pay higher dividends 8)
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Energy about the same but a lot more momentum amd better cross secrional density with the 14.3. But both hit hard enough, the more accurate of the two would be my first choice to hunt.
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Here's some interesting data from straightshooters that shows the FTT have a higher BC than the heavier JSB and Benji pellets; at least through their particular test gun.
http://www.straightshooters.com/beeman-r9-.20-beech.html#product-tabs-ourtake (http://www.straightshooters.com/beeman-r9-.20-beech.html#product-tabs-ourtake)
I might choose the least expensive, easiest to obtain pellets, all other things being equal.
Have fun!
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Here's some interesting data from straightshooters that shows the FTT has a higher BC than the heavier JSB and Benji pellets; at least through their particular test gun.
http://www.straightshooters.com/beeman-r9-.20-beech.html#product-tabs-ourtake (http://www.straightshooters.com/beeman-r9-.20-beech.html#product-tabs-ourtake)
I might choose the least expensive, easiest to obtain pellets, all other things being equal.
Have fun!
I agree! I'll go with something on the store shelf, or is usually in stock online, over something I have to order online or regularly is out of stock. As long as it performs adequately, even if the stuff i have to order or wait for performs better and costs less.
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It would be interesting to repeat the test at 30 and 50 yards to see the differences. I also think it would be more revealing as to which pellet to choose.
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It would be interesting to repeat the test at 30 and 50 yards to see the differences. I also think it would be more revealing as to which pellet to choose.
At that distance your in my neighbors yard! Lol
Actually look at the study above it is quite revealing. Has both pellets in the study. At 50 yards the two pellets have the identical energy. Physics is physics? I really believe it’s a macho thing that says a heavier pellets got to be better.
http://www.straightshooters.com/beeman-r9-.20-beech.html#product-tabs-ourtake (http://www.straightshooters.com/beeman-r9-.20-beech.html#product-tabs-ourtake)
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Using your highest velocity's I entered the info in Chairgun Pro this is what it came up with. You didn't specify which Benjamin pellet and there are two that weigh 14.3 so I used both. The heavier pellet has less drop and more energy. Accuracy being equal which one would you choose?
H&N 11.42 25yrd 0, drop at 50yrds.
Muzzle: 19.46 3.09"
25 yrds:11.62
30yrds:10.49
50yrds: 6.96
Benj. Diablo
Muzzle: 20.1 2.84"
25yrds: 15.11
30yrds" 14.28
50yrds: 11.41
Benj. Cyl.
Muzzle: 20.1 2.96"
25trds: 14.74
30yrds: 13.87
50yrds: 10.87
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Using your highest velocity's I entered the info in Chairgun Pro this is what it came up with. You didn't specify which Benjamin pellet and there are two that weigh 14.3 so I used both. The heavier pellet has less drop and more energy. Accuracy being equal which one would you choose?
H&N 11.42 25yrd 0, drop at 50yrds.
Muzzle: 19.46 3.09"
25 yrds:11.62
30yrds:10.49
50yrds: 6.96
Benj. Diablo
Muzzle: 20.1 2.84"
25yrds: 15.11
30yrds" 14.28
50yrds: 11.41
Benj. Cyl.
Muzzle: 20.1 2.96"
25trds: 14.74
30yrds: 13.87
50yrds: 10.87
Interesting may be better if you didn’t take the extreme but maybe 8 pumps? Your calculations from the program are at odds with the chart above which shows the energy the same at 25 yards and 50 yards? The Benjamins were the 20 cal. cyl. only ones made.
I think the very small difference in drop is that in my table the Benjamin at 12 pumps had a little more energy. At 8 pumps it would be the opposite?
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Different pellets behave differently from different barrels. Say that 5 time, fast! Also, the heavuer pellet from a springer may be starting off with less energy.
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Anyway, that is why I quit obsessing over ballistic coefficients. With pellets, especially in a spring gun, it can vary a great deal.
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Different pellets behave differently from different barrels. Say that 5 time, fast! Also, the heavuer pellet from a springer may be starting off with less energy.
But speed at the muzzle is speed at the muzzle? No matter what mechanisms got it there? Now where it’s headed is a different story?
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I checked the chart, looks like the benji cylindrical started off with 1 less fpe than the ftt in their r9. The ftt lost that 1 fpe advantage by the time they reached 50 yards.
Springers usually make a little more power with mid weight pellets, vs heavier ones.
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Anyway, it really does not matter. They will both kill pretty much the same, deoending on whether you can hit the kill zone.
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All things being equal I may be wrong but I would want a heavier pellet for hunting. More bullet mass means more kinetic energy and that equals to more damage.
But on the other hand a lighter pellet you will have more range I would think. So their you have it! I don’t have a clue. This will be interesting!!
I think your reasoning is what I have heard, but the energy is really the same? Its only different if they are traveling at similar speeds?
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Anyway, it really does not matter. They will both kill pretty much the same, deoending on whether you can hit the kill zone.
I’m not worried about it, just a intellectual exercise. The difference in energy between the Chart and the Chairgun Pro program at 50 yards is dramatic. Both can’t be right? If the Chart is from observation it would carry more weight? Assume the Chairgun Pro is calculating using math formulas?
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Using your highest velocity's I entered the info in Chairgun Pro this is what it came up with. You didn't specify which Benjamin pellet and there are two that weigh 14.3 so I used both. The heavier pellet has less drop and more energy. Accuracy being equal which one would you choose?
H&N 11.42 25yrd 0, drop at 50yrds.
Muzzle: 19.46 3.09"
25 yrds:11.62
30yrds:10.49
50yrds: 6.96
Benj. Diablo
Muzzle: 20.1 2.84"
25yrds: 15.11
30yrds" 14.28
50yrds: 11.41
Benj. Cyl.
Muzzle: 20.1 2.96"
25trds: 14.74
30yrds: 13.87
50yrds: 10.87
Interesting may be better if you didn’t take the extreme but maybe 8 pumps? Your calculations from the program are at odds with the chart above which shows the energy the same at 25 yards and 50 yards? The Benjamins were the 20 cal. cyl. only ones made.
I think the very small difference in drop is that in my table the Benjamin at 12 pumps had a little more energy. At 8 pumps it would be the opposite?
The chart you posted the link to shows the lighter pellet starting with more energy than the heavy one.
Tomorrow I'll play with it some more, have to work tonight. BTW Chairgun shows two .20 Benjiman 14.3gr pellets, i don't shoot .20's so I don't know.
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45flint here's the link to download Chairgun Pro. It's not a end all do all but it is fun to play with, like any other program it's only as good as the data input is.
https://us.hawkeoptics.com/chairgun.html
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45flint here's the link to download Chairgun Pro. It's not a end all do all but it is fun to play with, like any other program it's only as good as the data input is.
https://us.hawkeoptics.com/chairgun.html
Thanks
Found this when reading about bullets mass vs velocity. Velocity is more powerful in calculating kinetic energy.
“It really comes down to the physics, bear with me here...
Kinetic energy is what they list as "muzzle energy", using the muzzle velocity and the bullet weight. The equation is as follows for kinetic energy:
Energy = 1/2 * Mass * (Velocity)^2
Because velocity is squared in that equation, if you double the velocity, the energy is multiplied by 4, while if you double the mass, the energy is simply doubled.”
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If you start two pellets out with the same muzzle energy, the one that arrives downrange with the greater muzzle energy will be the one with the better Ballistic Coefficient.... The BC is a measure of how quickly the pellet loses velocity, and hence energy....
Chairgun lists the BC of the H&N FTT 11.5 gr. pellet as 0.025, but the Beeman H&N Match as only 0.016.... It shows the BC of the Benjamin 14.3 gr. cylindrical pellet as 0.023, and the Benji Diabolo as 0.025.... The only place your two pellets have close to the same energy is at 7 pumps.... Here is what ChairGun gives.... I used the two pellets that had the same BC = 0.025....
H&N FTT @ 736 fps.... @ 25 yd = 650 fps (10.80 FPE)…. @ 50 yd = 576 fps (8.46 FPE)
Benji Diabolo @ 660 fps.... @ 25 yd = 584 fps (10.83 FPE)…. @ 50 yd = 517 fps (8.48 FPE)
However if you are using the Benji Cylindrical (BC = 0.023) @ 660 fps.... @ 25 yd = 578 fps (10.80 FPE)…. @ 50 yd = 506 fps (8.12 FPE)
As you can see, the lower BC has a bit less FPE as it goes downrange.... If the BCs were more dramatically different so would be the energy downrange.... Generally, heavier pellets have a better BC than light ones if the shape is the same....
Bob
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H&N FTT @ 736 fps.... @ 25 yd = 650 fps (10.80 FPE)…. @ 50 yd = 576 fps (8.46 FPE)
Benji Diabolo @ 660 fps.... @ 25 yd = 584 fps (10.83 FPE)…. @ 50 yd = 517 fps (8.48 FPE)
However if you are using the Benji Cylindrical (BC = 0.023) @ 660 fps.... @ 25 yd = 578 fps (10.80 FPE)…. @ 50 yd = 506 fps (8.12 FPE)
This makes sense. It to me is what I would expect, thanks
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45flint here's the link to download Chairgun Pro. It's not a end all do all but it is fun to play with, like any other program it's only as good as the data input is.
https://us.hawkeoptics.com/chairgun.html
Cool program. Been playing with it
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Is all this theoretical or has it been measured by any means indicating how much of a wallop different weight pellets deliver at different distances. Theory is sometimes one thing real world another. Just wondering.
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Is all this theoretical or has it been measured by any means indicating how much of a wallop different weight pellets deliver at different distances. Theory is sometimes one thing real world another. Just wondering.
Theory is always tested by doing, both are fun. Much of this only influences long shoots well beyond my backyard. But it’s all interesting. Ballistic Coefficient of different pellets is interesting but it’s influences for most of us is immaterial?
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What I was looking for is a link to where an actual test was done to prove or refute the actual delivered energy upon impact.
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Ballistics Coefficients come from real world testing, where the velocity downrange is measured and compared to the muzzle velocity.... It is very important in terms of the delivered energy and momentum downrange.... For example, a wadcutter like the H&N Match has a much lower BC of only 0.016.... Using that instead of the 0.025 of the H&N FTT, starting at the same MV of 736 fps, we get....
MV = 736 fps.... @ 25 yd. = 607 fps (9.41 FPE)…. @ 50 yd. = 501 fps (6.41 FPE)….
Just changing the BC from 0.025 to 0.016 drops the energy at 25 yards by 13%.... and at 50 yards by 24%.... In addition, the pellet, moving slower, will drop more....
Here is a link to the most extensive BC testing currently available.... https://hardairmagazine.com/ballistic-coefficients/
Bob
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Thanks, I find it interesting even though I don't do the math I just kill paper targets.
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Ballistics Coefficients come from real world testing, where the velocity downrange is measured and compared to the muzzle velocity.... It is very important in terms of the delivered energy and momentum downrange.... For example, a wadcutter like the H&N Match has a much lower BC of only 0.016.... Using that instead of the 0.025 of the H&N FTT, starting at the same MV of 736 fps, we get....
MV = 736 fps.... @ 25 yd. = 607 fps (9.41 FPE)…. @ 50 yd. = 501 fps (6.41 FPE)….
Just changing the BC from 0.025 to 0.016 drops the energy at 25 yards by 13%.... and at 50 yards by 24%.... In addition, the pellet, moving slower, will drop more....
Here is a link to the most extensive BC testing currently available.... https://hardairmagazine.com/ballistic-coefficients/
Bob
Bob thanks for this data, very interesting.
For one there seems to be no testing of 20 cal. pellets?
But look at a common pellet I use all the time, RWS SuperDomes in .177 and then in .22. The ballistic coefficient of the lighter .177 is greater than the .22. The opposite of what I was hearing: Heavier pellets have better BC? Goes to show you, you need to shoot them not just do the math?
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There are MANY variables that go into the BC, the weight is not the answer unless you are comparing pellets of the same caliber.... In different calibers you need to use the Sectional Density, which is the "weight per unit area".... The SD is also one of the two main criteria affecting penetration in a soft target, the other being velocity....
The BC has two main factors, the SD and the shape, expressed as the Form Factor.... They are related by.... BC = SD / FF …. so even if two pellets have the same SD, they can have a different BC because they have different shapes.... To make things even more complicated, the BC of a pellet is not a constant, it depends on the velocity.... and to some extent the gun it is fired from.... because the shape of the pellet changes from the pressure propelling it down the bore.... Check out this photo....
(http://i378.photobucket.com/albums/oo221/rsterne/Ballistics/Pellet%20Obturation_zpsyzq1fbkq.png) (http://s378.photobucket.com/user/rsterne/media/Ballistics/Pellet%20Obturation_zpsyzq1fbkq.png.html)
Those are JSB Exacts, the 2 on the left were fired, while the 2 on the right were just pushed through the barrel with a dowel.... How much the skirt changes shape depends on the pressure, the hardness of the lead, and the thickness of the skirt.... The bottom line is that the BC is the governing factor in how the pellet slows down as it travels downrange.... However, the only way to get the exact BC for your gun and pellet is to test it.... The published numbers are only a guide.... Having said that, a wadcutter will have much poorer downrange performance than a round nosed pellet of the same weight, and pointed and HP pellets are somewhere in between.... and when you compare pellets of similar shape and different weight (in the same caliber) the heavier one should have a higher BC....
Bob
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So when all this pellets being shot are they weighed and measured to make sure your data is correct. Do you just get them out of the tin. I don't know if this factors in to the equation
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There will obviously be some slight difference from pellet to pellet.... I believe HAM shoot 10 pellets through their LabRadar and take the average near and far velocities to use for their BC calculation.... There is probably more variation in the velocity from shot to shot in most guns than the change in BC from pellet to pellet....
Bob
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Here is my comparison of two pellets in my Sterioded Benjamin-Sheridan Silver Streak in 20 cal. The H&N 11.42 grain and the Benjamin 14.3 grain. The test showed basic physics works: energy is about equally but speed changes. If accuracy is the same what would you prefer? My assumption would be target shooter wants the speed and hunters want the heavier pellet? But energy is the same?
Pumps. FPS H&N 11.42. FPS Benjamin 14.3
3. 523. 471
4. 592. 528
5. 648. 583
6. 697. 12.32 FP. 610. 11.84 FP
7. 736. 13.74. 660. 13.84
8. 776. 15.27. 686. 14.95
10. 829. 735
12. 876. 19.46 FP. 794. 20.02 FP
Wouldn't the "speed of light" pellet have infinite mass (https://www.physicsoftheuniverse.com/topics_relativity_emc2.html), and therefore a higher FPE than the slower, heavier pellets?
Oh, wait.
Never mind.
-Whirly
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Here is my comparison of two pellets in my Sterioded Benjamin-Sheridan Silver Streak in 20 cal. The H&N 11.42 grain and the Benjamin 14.3 grain. The test showed basic physics works: energy is about equally but speed changes. If accuracy is the same what would you prefer? My assumption would be target shooter wants the speed and hunters want the heavier pellet? But energy is the same?
Pumps. FPS H&N 11.42. FPS Benjamin 14.3
3. 523. 471
4. 592. 528
5. 648. 583
6. 697. 12.32 FP. 610. 11.84 FP
7. 736. 13.74. 660. 13.84
8. 776. 15.27. 686. 14.95
10. 829. 735
12. 876. 19.46 FP. 794. 20.02 FP
Wouldn't the "speed of light" pellet have infinite mass (https://www.physicsoftheuniverse.com/topics_relativity_emc2.html), and therefore a higher FPE than the slower, heavier pellets?
Oh, wait.
Never mind.
-Whirly
The Einstein Pellet
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I still have a hard time understanding the pointed pellets have a lower bc than domed?
Someone who wants to try to put it in simple terms explain.
Is it something to do with the skirt or what?
I know pb'ers bullets, don't the sharp pointed do better than round nose?
This stuff is Greek to me...no wait... I know some Greek and still this is more a mystery...
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I gather from the photo you posted that the pellet on the far left has a lower bc . I came to that conclusion because of the skirt deformation. You would have losses because of the imperfect seal and increased drag but I Don't know what medium it was fired into I assume water. So if that deformation happened in the barrel that pellet has to have a lower bc. Is this the response you were looking for?
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Luke, pointed pellets for airguns typically have a conical nose, a straight taper that ends in a sharp corner at the back of the head.... It is that corner that causes additional drag compared to a round nose pellet.... I have never seen a conventional airgun pellet with a Spitzer nose like a rifle bullet.... although some of the very powerful PCPs do use bullets now.... and they have much less drag than any pellet....
Joe, the 2 pellets on the left were fired into a bucket loosely stuffed with grocery bags.... They stretch to stop the pellet and recover it with no damage.... The skirt of the pellet is expanded into the rifling by the air pressure behind it, and increases the seal, as it is designed to do.... There is no way of knowing whether the BC of the 2 pellets on the right is better or worse, because they were never fired.... The point of that photo is to show you how much the shape of the pellets changes on firing.... and the exact shape when it leaves the muzzle will depend on the air pressure and the diameter of the barrel.... That is the reason that the same pellet, fired from different guns, can have a different BC....
Bob
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There are MANY variables that go into the BC, the weight is not the answer unless you are comparing pellets of the same caliber.... In different calibers you need to use the Sectional Density, which is the "weight per unit area".... The SD is also one of the two main criteria affecting penetration in a soft target, the other being velocity....
The BC has two main factors, the SD and the shape, expressed as the Form Factor.... They are related by.... BC = SD / FF …. so even if two pellets have the same SD, they can have a different BC because they have different shapes.... To make things even more complicated, the BC of a pellet is not a constant, it depends on the velocity.... and Check out this photo....
(http://i378.photobucket.com/albums/oo221/rsterne/Ballistics/Pellet%20Obturation_zpsyzq1fbkq.png) (http://s378.photobucket.com/user/rsterne/media/Ballistics/Pellet%20Obturation_zpsyzq1fbkq.png.html)
Vintage Streak replies
So the pellet on the far left is not deformed in an irregular way but essentially looks the same as the one next to it is that it. The picture to me it seems that it has a shape not conducive to sealing. Is it just shadows that make it appear to be deformed?
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Thanks for that explanation Bob, it makes sense, that the shoulder will cause drag.
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All things considered, I do typically go for the heavier accurate pellet. Heavier pellets penetrate better, that is my reasoning. As for flat trajectory, i use open sights on all my airguns. I am not confident past 25 meters with them, not because the gun won't group but because of my sight picture with open sights. When you properly focus on the front post, the target is too blurry and it gets worse as the range increases. When I just line my sights up and focus on the target, the groups open up, so that decreases my effective range. I have 20/15 vision and perfect color vision, so there is that.
If you are pushing more than 600 feet per second at the muzzle, you should have plenty of useful trajectory for a 25 meter shot.