Massive ballistics project

[jonny75904]

I have been undertaking a rather large project as of late - gathering and comparing a number of data points on 39 popular pellet styles.

I started with 10 pounds of refrigerated glycerin, fired the pellets into rows of 5 or 6, by brand or style. Then I froze the block, took measurements of the entry-point diameters, the depth of penetration, and photos of the pellets' ballistic travel. I also took before / after measurements and photos of each pellet to capture deformation information.

i have yet to finish chronographing - I am doing two 10-shot strings for each pellet - one at muzzle, one at 15 yards (my usual distance).

Is anyone interested in the data and results?

 

[Guest]

I'm interested in the purpose of the study. Personal, work related, looking to improve upon the design for target shooting, hunting? You've piqued my interest.

 

[mij]

of course the data must be shared, I would like to see you include pellet fragmentation/expansion to analyze as pest elimination efficiency, and which makes the cleanest hole on paper

 

[socaloldman]

What a huge amount of work. I would think there is great interest in the information. I for one will look forward to your results.

 

[SquirrelWar2]

Looking forward to this! Would be good to know which pellets out there are the best, maybe like a top-10 list? That way people can skip the trial and error, and just buy the good stuff? ☺

 

[jonny75904]

Main reason is personal - to truly know my gun, what it likes to shoot, what it doesn't, etc.

Had a few surprises here and there, a few disappointments, and I'm still working on formatting the data into useable figures.

there are definite trends for each design - I've roughly come up with two new units of measure to describe if a pellet is "pushy" or "punchy," as we all know it isn't all about one or two specific measurements.

 

[jonny75904]

One other thing to note, the rifle used is a gamo whisper cat - spring piston break barrel.

It averages 10fpe fairly consistently, which is why I decided to do such a massive test - I know with reasonable certainty that each pellet had 10fpe upon entry, whereas a PCP has the constant challenge of pressure dropping and having to keep an eye on it.

Also, in terms of a top 10 list, it is subjective to so many variables as I have come to find out. In the case of my gun, pellet mass seems to effect lateral travel as well as vertical travel for the POI. I would've never associated lateral movement with mass, but with my gun it apparently can.

some pellets fire with ES = 3 and SD = 2, while others were all over. And everybody's go to pellet - JSB Exact - doesn't quite have the pest control potential I had hoped for with my gun, but they're consistent ballistically so there's that.

Several pellets had zero / negligible deformity, registering .01mm to 0.03mm difference in measure, while some of the hollow points ended up wider than their length.

 

[Michael]

Absolutely! A while back I started a BC chart but haven't had time to gather data for it. You can find it at the top of the Pellets, Projectiles, Ammo section. 

Or follow this link
https://docs.google.com/spreadsheets/d/1tHFCBSX6dMAFCG1ogWV8ofSFM0w6xj9XsabW8QV7G-I/edit?usp=sharing

Thanks! 

 

[jonny75904]

Very nice!

I need some feedback from veterans as to what's valuable on hollow points. There are several distinct behaviors the hollow points follow:

​1. Expand, separate, continue with penetration / wound channel creation. Crosman Destroyer I believe is well-known for this.
​2. Expand, no separation, maximizes energy transfer, minimizes over-penetration. 
​3. "Pointed" hollow points, such as Predator Metal Mag and Gamo's Red / Blue tipped hollowpoints. The points tend to sheer out, and in the case of Gamo's red tips, results in a donut-shaped projectile continuing forward.

​The problem with each is how to come up with consistent apples-to-apples measurements. The final pellet diameters are significantly larger/smaller, depending on separation, and the depths vary widely based on whether the pellet separates and penetrates. From a numbers perspective, some are fat and shallow, some are skinny and deep, some "change mode" halfway through. 

What is the best way to present data for these behaviors?

 

[jonny75904]

First set of results are in. These are 12 varieties of H&N, pulled from two of their samplers. Because they're all the same brand, and same samplers, I shot them all together into two rows.

Individual photos will follow - uploading these one at a time is a pain...

Power is assumed to be approximately 10fpe per shot. Because I was shooting straight down, point blank, I did not wish to mess with a chronograph - I was more focused on consistent angles and heights, lest I cross two pellets on accident....

First row of six are from the H&N Field Target Pellets sampler:
Field Target Trophy, in 4.50mm, 4.51mm, and 4.52mm
Baracuda Match, in 4.50mm, 4,51mm, and 4,52mm

The second row of six are from the Sport Hunting Pellet sampler
Silver Point
Crow Magnum
Baracuda Power
Baracuda Hunter Extreme
Field Target Trophy
Field Target Trophy Green

Field target sampler, in order listed above, from left to right

Before and After. Nothing very remarkable about these target pellets. They're all very close in performance, and the differences seem to be negligible. If you're into pellet sorting, I would go with these pellets for the ability to choose your head diameters.

Hunting Sampler, in order listed above, from RIGHT TO LEFT (I turned the block around)

Before and After:

Silver Point: Nothing remarkable - medium punch, excellent pierce, mild deformation, performed well

Crow Magnum: Very interesting hollow point. This one managed to mushroom, separate, but still stay together. I suspect a multi-shot test of this pellet would produce separation behavior, but this test was one-shot-one-chance for all pellets.

 

Baracuda Power: Less punch and pierce than the other pointed and domed pellets, but zero deformation. This leads me to believe this pellet is very hard and strong, perfect for hard targets.

Baracuda Hunter Extreme: AWESOME. Simply awesome, and my favorite hollow point. Highest punch factor of all the pellets I tested. Mushrooms into a square surface, and it appears it is designed to stay intact, making this an "all-punch" hollowpoint with minimal over-penetration. Excellent for soft targets.

 

Field Target Trophy: Nothing remarkable, typical dome pellet. Medium punch, medium pierce, minimal deformation.

Field Target Trophy Green: Similar to Baracuda Power but with better piercing and also zero/negligible deformation

 

[Quad82]

Great! It's fun and interesting. I have done this for every pellet and rifle I have owned. Fishing lure boxes with the dividers work great to keep them organized too. I have also glued a new and a shot/mushroomed pellet on a sheet of cardboard. My son has just graduated college and has always done this type of testing too. Now he is doing it for one of the large bullet makers. Kind of cool to see I rubbed off a little on him. Waiting to go with him on some paid big game testing!

 

[jonny75904]

I added more pictures to my earlier post...This post will also have to be done in several edits, so expect more content soon...

Next up is RWS. I hadn't heard of them until recently, and I thought their pellet designs were unique and interesting. The package features two wad cutters, a domed, pointed, and hollow point design.

All of these pellets deformed to some degree, and their entry point diameters were all larger than the H&N, and still had comparable depth of penetration. 

From left to right, pellets are:
RWS Meisterkugein
RWS Superdome
RWS Hobby
RWS Superpoint
RWS Super HollowPoint (hollow point broke free and flattened to follow core)

RWS Meisterkugein, Wad cutter

RWS Superdome

RWS Hobby

RWS Superpoint

RWS Super HollowPoint (hollow point broke free and flattened to follow core)

 

[Alan]

A few comments.

Lateral displacement (lelf-right POI) is a well known phenomena in all projectile weapons. One could argue the reasons perhaps, but in an airgun, the primary cause is barrel vibration. 

The Whisper Cat is a .177 caliber weapon with limited muzzle energy (≈10 FPE). The hardness of pellets vary somewhat, but not to the extreme some folks believe. This fact is caliber independent. As the caliber, mass, sectional density, ballistic coefficient, and velocity increase, the post-impact ballistics (deformation, terminal deflection, etc.) increases as well. How much depends on many factors, some of which are not in evidence—even rifling twist can cause a significant difference in the observed results.

While in-barrel ballistics and in-flight ballistics are well known and well defined, post-impact ballistics remains a controversial, and often disputed, science. This said, I'm not surprised at the outcome you observed. 

By the way, I've never use chilled glycerin as a medium, although I have used other media including florist's foam. Shooting the water-soaked foam with a .177 caliber airgun typically doesn't blow the foam apart. Shooting it with a .25 caliber airgun, almost completely destroys it., and it isn't pellet shape which causes this!

 

[jonny75904]

I'm very satisfied with the glycerin as a ballistic medium, but it is not without its pros and cons

Pros
1. Availability: Found at any hobby / hippie supply shop with soap-making materials
2. Usability: It has minimal "self-healing" behind the shot. The ballistic channel stays nice and open all the way to the tail of the projectile
3. Reusability: Melt it in the microwave, and it is solid by the next morning, or, chill it in the freezer.
4. Easy to use: Slices with a wire. Smoothing the surface to get a clear image is very easy - pour water over it, smooth with finger, then a bit more water to rinse.
5. Easy visual results: Visual inspection reveals a lot of information, and quickly.

Cons
1. Thermal sensitivity: Using an infrared thermometer, I was surprised as how quickly it warms up. Fresh out the freezer, the surface temp went from 5F to 55F in 15 minutes, making entry-diameter measuring a poop-show in no time flat.
2. Price - I paid $40 for a ten pound bucket. as you can see, it's perfect for .177, but for higher calibers one would need significantly more. The price would get out of control quickly, and melting that much glycerin poses its own challenges
3. Mess - it's soap... ish. I did my best to contain the shavings, but, it gets on your hands, and on everything you touch. You can wear gloves, but, taking them off and on when trying to go between the camera, glycerin, laptop, pen, back to glycerin, etc, makes gloves impractical. Pouring water to get clearer images makes this very messy, but, the results are clear.
4. More Manpower - Because of the mess factor above, it is best done with two people - one with gloves, managing the block, the other to manage everything you want to keep clean.
5. Difficult measurements - it gets soft, fast, even after freezing.

Moot point
1. It's scented slightly, so heating it creates an aroma.

Recommendations for use:
1. Use a large double-boiler for heating if you have higher calibers... MAYBE the oven if you're not using a plastic container.
2. Two or more people
3. Do not take measurements directly. Instead, fill the cavities with clear resin, then melt the glycerin off. I have yet to do this, but, after all my hard work, I'm seeing very high margin of error in the measurements I took. The kinematics are inconsistent enough to where I cannot completely trust the data.
4. If you must transfer between containers, do it when the glycerin is cool, not hot - it saves precious expensive glycerin by not coating the inside of the old container with liquid glycerin. As a solid, it pops out easily.
5. Remember that it is soft, like stick butter, and thus sensitive to shock. When I first removed the glycerin for measuring, I turned the bucket upside down, and popped it out onto the counter. Problem is, that flattened the entry holes a bit, but only at the surface. I took my measurements from several mm in.

Unknown:
How much glycerin will dissolve into liquid resin poured into the ballistic channels? How warm does resin have to be to maintain high liquidity, low viscosity, fill the cavities quickly, purge bubbles, and harden? A chillable resin seems ideal if there's one that can maintain low viscosity and self-purge itself of air bubbles....

 

[jonny75904]

"Alan"A few comments.

Lateral displacement (lelf-right POI) is a well known phenomena in all projectile weapons. One could argue the reasons perhaps, but in an airgun, the primary cause is barrel vibration. 

The Whisper Cat is a .177 caliber weapon with limited muzzle energy (≈10 FPE). The hardness of pellets vary somewhat, but not to the extreme some folks believe. This fact is caliber independent. As the caliber, mass, sectional density, ballistic coefficient, and velocity increase, the post-impact ballistics (deformation, terminal deflection, etc.) increases as well. How much depends on many factors, some of which are not in evidence—even rifling twist can cause a significant difference in the observed results.

While in-barrel ballistics and in-flight ballistics are well known and well defined, post-impact ballistics remains a controversial, and often disputed, science. This said, I'm not surprised at the outcome you observed. 

By the way, I've never use chilled glycerin as a medium, although I have used other media including florist's foam. Shooting the water-soaked foam with a .177 caliber airgun typically doesn't blow the foam apart. Shooting it with a .25 caliber airgun, almost completely destroys it., and it isn't pellet shape which causes this!

Very good info to have - I was unaware of several of these factors. I'll know more once I get the shot strings done and chrono'd.

I still have quite a bit more data and photos to share - finding time is a challenge, especially due to the limited upload capabilities of this site - a multi-upload extension would go a long way.

 

[Guest]

Great info Jonny. Ive seen tests of these pellets here and there but nothing this extensive and you say there is more to come. I'll be saving this info to my hard drive, maybe even printing it out to put in a binder once all your tests are uploaded. I love it.

 

[jonny75904]

JSB and crosman are next

 

[tutuan]

Awesome. Really appreciate your effort putting into this.

 

[jonny75904]

Next up was the sampler pack from JSB. As other posters have pointed out, the gun I use is not known for its consistency, but, that did not stop this JSB Diabolo pack from being a consistent performer on velocity and shot string (from a previous test, before I took on this massive endeavor).

Despite using a Gamo Whisper Cat .177 spring piston rifle, the JSB Match Diabolo Exact / Exact RS had very small ES and SD.

The Exact had an average of 776, with ES=7 and SD=2.
The Exact RS had an average of 823, with ES = 11 and SD=3.

This leads me to believe the JSB Exact Diabolos are highly consistent in their manufacturing characteristics, and are ideal for accuracy with my gun in particular.

The pellets featured below are:JSB Match Diabolo ExactJSB Match Diabolo Exact HeavyJSB Match Diabolo Exact, RSJSB Match Diabolo StratonJSB Jumbo (I had to throw the fatboy in there)

Exact / Exact Heavy / Exact RS / Straton / Jumbo

Exact / Exact Heavy / Exact RS / Straton / Jumbo

Exact / Exact Heavy / Exact RS / Straton / Jumbo

 

All the pellets had a piercing impact and penetration. The top performer was the Exact Heavy, followed by the Exact. The RS and the Exact performed near identically. The Straton brought up the rear.

The jumbo did not do so well, but frankly a pellet that heavy coming from a low energy rifle can only be so successful, IMO. In an upcoming post, I have the H&N sniper magnum in the mix - it is even heavier than the jumbo.

JSB Exact

Tied for a close second with the RS, I get consistent ballistic characteristics from this pellet. I haven't chrono'd all of these, nor have I POI'd all of these (I'm not gonna go that far either).

Next up was the Exact Heavy. This was the deepest penetrator of all the JSB, which was not what I expected - I was expecting the Jumbo to be the hardest bus to stop, but that's not what happened. It has one of the smallest entry-points of all the JSBs, which I interpret as having a more piercing impact characteristic.

Third up was the Exact RS. This pellet performed nearly identical to the Exact - visual inspection of the ballistic channels shows no readily-apparent difference. If you're stocking up on JSB, I'd say buy a tin of one or the other, but not both (unless you just really love JSB and feel incomplete).

Next up was the Straton. I was disappointed with it (and with all pointed pellets). It goes counter to logic that a pointed pellet penetrates less. The only explanation that makes sense to me is the increased surface area of the point over a dome causes more braking. The entry point is noticeably wider, perhaps an attribute of the point. But, I did not expect a pointed pellet to penetrate less than its rounded cousins.

Finally, I tried the JSB jumbo. This one disappointed all around with my gun. I think it needs a much higher power .177 behind it.

 

[jonny75904]

Next up was Crosman. The takeaway from the Crosman series is that the Destroyer lives up to its name. Not only is it the most destructive Crosman pellet I fired, it is arguably the most destructive of all the pellets I fielded. Very large entry port means this pellet hits with a very big punch - perhaps the biggest punch of the set - and it also penetrated the deepest.

I had always looked at the picture on the pellet tin and chuckled, thinking what a gimmicky pellet design this must be, but this test has shut my stupid mouth right up.

NOT ALL OF THESE ARE CROSMAN. There is an H&N Baracuda in there, second to last, followed by a Crosman superpoint. Both were tins I found late in the game.

WadCutter - as one might expect, the wad cutter hits with a substantial punch, on par with the hollow points but without the expansion and follow through. It's all mostly punch then a trickle-down stop, which is pretty much what it was designed to do - punch through a target quickly with minimal follow-through.

Next up, the over-achieving Destroyer. Devastating impact, and devastating penetration. The pellet - clearly meant for hunting - looks to be a suitable selection for both head and body shots. No matter where you aim, understand this pellet is going to hit hard and penetrate deep. \\

Next up is my first-favorite, the Premier Magnum. Available over the counter at most sporting good stores, it is a heavy pellet, accurate, and has a very piercing, penetrating impact. Very little deforming shows this pellet does not waste any energy on deformation.

Next up was the Piranha. It's essentially a Magnum with a meat-grinder on the front. Supposedly. It disappointed. The pattern on the front appears to do little more than add surface area and brake the pellet faster. Someone please explain this pellet to me. It does not seem to do well. so unless there's a special purpose to this one, I'm just kinda stumped.

Skipping over the H&N, the last pellet shot in this group is the Superpoint, and this one performed very well. As far as punch goes, it falls between the Destroyer and Magnum. Penetration channel is shorter than the others, but noticeably wider. This leads me to believe this pellet will deliver comparable punch on impact, cut a wider wound channel, with less of a chance of over-penetration, but that may also be a bit presumptuous.