A Little Food For Thought On Slug Expansion

[AirgunBill]

I was going to wait till I did more testing but with recent posts about how well slugs expand I thought I would share some initial testing I have done. In the video I am using the 'Clear 20% Ballistic Gel' and a ground walnut media to catch the slugs. I particularly was interested in how much expansion was occurring on lighter weight pests like birds. My thought was with their lighter body weight and lighter frame there would not be enough resistant to result in much slug expansion. I think the devastating results on pest birds is more to do with the typical starting higher fpe, fps and in many cases higher weight of the projectiles themselves. Not to mention the higher down range energy compared to pellets. As some others have mention the devastating results we see have less to do with slug expansion on the lighter weight birds and more with just higher kinetic energy on impact. As body weight goes ups and pest and game with heavier skeletons are hit you would expect to see more resistance and expansion of the slug. I hope to down the road actually pick up some of the pests I shoot and do some testing on them. No saying that any results are 100% correct but it is some food for thought. Bill

https://www.youtube.com/watch?v=f6jsPP3Z9Fg&t=2s&ab_channel=GunPowder%26AirPower

 

[Leatherman]

It has been shown in high speed photography that bullets expand rapidly immediately upon impact within 1” of penetration . I am referring to tests with jacketed bullets out of powder burners but I would believe the same would be with lead bullets and hollow point slugs in Airguns. These tests were done in ballistic jell . Actual results in animals would probably would differ with tissue density ( wild boar vs sparrow) and wether bone was immediately a factor too. The design of the slug and its hollow point will be a big factor in how much expansion Is possible. Take a look at the new FX 22 grn. .22 slugs now at Pyramid Air. It has a large pear shaped hollowed cavity which should give superb expansion compared to just a straight cavity hollow point . This design is very much the same design that Rat Sniper slugs were made and I can attest that they open up in small birds and most of the time do not penetrate squirrels at 30 fpe. I just ordered some of the FX slugs and hope they shoot as well as the Rat Sniper slugs did. They shot better than any slug I tried but I ran out and Rat Sniper isn’t taking orders. Perhaps FX bought him out??

 

[AirgunBill]

If you noticed in the Utah Airgun video shooting the new FX slugs was into a full size gel block that weighs about 10 pounds. That is a lot more resistance than that of a 2 to 4 ounce sparrow or starling. I have not shot my slugs into a full size/weight ballistic gel block yet but I have into clay, and like Justin got the same flat pancake. So that would not approximate shooting birds or probably midsize game. Not looking for an argument but how do you know how much your slugs open up on a small bird or have you somehow been able to recover the slug. Also comparing firearms shooting bullets at 2500 to 4000 fps is a totally different situation. I so far have only shot the NSA slugs and still venture to say the devastation on small birds is more about kinetic energy. Bill

 

[Cranky1]

I’ve noticed on game that slugs, even though they are slower, are much louder impacting. I’ve shot several starlings with mk2 heavies, polymags, vk slugs, barracuda hunter and hunter extreme. The vk hit the loudest with the most feathers flying and largest exit. The polymag has been second for huge exit holes and feathers flying. Barracuda hunter were third, then extremes with diabolo shaped last. Basically these were all shot out of my r5m long from the same chair in the same tree so the only factor besides a yard or two is the projectile. Most of these shots have been 30ish yards. 

While I have not recovered the projectiles I firmly believe there has to be expansion do to the devastation, the vk slugs were the only ones to practically blow a sparrow in half.

I’m itching to try the hades 25, I’m using the 22 cal and have been pretty impressed with them, accuracy and the exit size. 

 

[Vadimas]

I hunt with slugs without a hole,they work great.

Mod edit: graphic hunting photos deleted Hunting forum only

The photo shows the damage it leaves.

 

[AirgunBill]

I hunt with slugs without a hole,they work great.
Mod edit: graphic hunting photos deleted Hunting forum only

The photo shows the damage it leaves.

Curious what is the weight of that slug is and the fpe your are generating and how much more it is than the typical pellet shooting air rifle. It might be the difference between hitting something with a standard hammer verse a sledge hammer. Bill

 

[Cranky1]

Bill are you trying to say that a hollow point does less good then shooting a heavier projectile of the same caliber out of the same gun? Or are you trying to say a 60ftlb monster redesigned vs a 30ftlb nsa slug?

Ive seen the same in 22 as I have with 25 cal air rifles. The hollow point style gives larger exit holes. I’ve gotten birds with monster redesigned and poly mags. The polymag leaves a lot larger exit hole. 

 

[AirgunBill]

Bill are you trying to say that a hollow point does less good then shooting a heavier projectile of the same caliber out of the same gun? Or are you trying to say a 60ftlb monster redesigned vs a 30ftlb nsa slug?

Ive seen the same in 22 as I have with 25 cal air rifles. The hollow point style gives larger exit holes. I’ve gotten birds with monster redesigned and poly mags. The polymag leaves a lot larger exit hole.

What I am saying is that the level of expansion many are claiming with slugs in birds and smaller game is not occurring unless you hit a solid bone. The larger exit hole has more to do with increase fpe required to shoot the heavier weight of the slug. This results in a bigger exit hole not because of super expansion but just because of increased kinetic energy. People are doing testing using heavy dense clay blocks and even heavy full size ballistic gel blocks that weigh much more than the pests and small game we are shooting. Shooting these over sized blocks will give much more resistance to the pellet or slug than the actual weight of said pest or game. I have not shot polymags into the 'Clear Ballistics Gel' that weigh the same as the target pest or game to see how they expand. I will say just having a sharper edge or flatter head pellet alone even without much expansion will leave a bigger hole than a dome pellets. The flatter head like in the polymag or H&N Terminator just transfers more energy into the target and cuts a better wound channel. The domes like monster redesigns will pencil they way through game. Have you ever noticed how the Terminators and Polymags just cut nice holes in paper targets. 

 

[Cranky1]

Bill are you trying to say that a hollow point does less good then shooting a heavier projectile of the same caliber out of the same gun? Or are you trying to say a 60ftlb monster redesigned vs a 30ftlb nsa slug?

Ive seen the same in 22 as I have with 25 cal air rifles. The hollow point style gives larger exit holes. I’ve gotten birds with monster redesigned and poly mags. The polymag leaves a lot larger exit hole.

What I am saying is that the level of expansion many are claiming with slugs in birds and smaller game is not occurring unless you hit a solid bone. The larger exit hole has more to do with increase fpe required to shoot the heavier weight of the slug. This results in a bigger exit hole not because of super expansion but just because of increased kinetic energy. People are doing testing using heavy dense clay blocks and even heavy full size ballistic gel blocks that weigh much more than the pests and small game we are shooting. Shooting these over sized blocks will give much more resistance to the pellet or slug than the actual weight of said pest or game. I have not shot polymags into the 'Clear Ballistics Gel' that weigh the same as the target pest or game to see how they expand. I will say just having a sharper edge or flatter head pellet alone even without much expansion will leave a bigger hole than a dome pellets. The flatter head like in the polymag or H&N Terminator just transfers more energy into the target and cuts a better wound channel. The domes like monster redesigns will pencil they way through game. Have you ever noticed how the Terminators and Polymags just cut nice holes in paper targets.

While I will agree with some of this I’m shooting a 32.8 grn vk slug with the same exact gun with no changes as I shoot pellets. Being that slugs have more drag, they are probably making less energy then my polymags and leaving a much larger exit hole. 
If I get time tomorrow I will shoot both across the chrony and give you the FPS. So I definitely agree that if I cranked my gun up for the slugs they would cause more damage, but my gun is set the same. 

 

[Vadimas]

I hunt with slugs without a hole,they work great.
Mod edit: graphic hunting photos deleted Hunting forum only

The photo shows the damage it leaves.

Curious what is the weight of that slug is and the fpe your are generating and how much more it is than the typical pellet shooting air rifle. It might be the difference between hitting something with a standard hammer verse a sledge hammer. Bill

Slug 35gr 935fps.

Tests were conducted during the hunt,the damage results are very similar,in hunting on small animals slug with a hole is useless.

 

[Leatherman]

I’d like to see a test using a small block of ballistic jell about 1 1/2” thick In a weight to replicate the thickness and weight of say a starling or squirrel rib cage. Set it up free standing so the jell moves upon impact just like an animal would. A sheet of Kevlar behind to catch the slug or pellet so you can see what expansion you truly are getting between the different types of projectiles. Then shoot them at 850 FPS and 950/1000 FPS and see if there is a significant difference. Shooting a big heavy block of Ballistic jell just doesn’t replicate actual conditions. As I stated in another thread full expansion happens within the first inch of impact. I also believe though there is a significant difference in tissue density between animals. So a bird would have different results when compared to say a squirrel. And of course bones would have a huge effect on the results. Birds have hollow soft bones when compared to mammals. Those who have shot ground squirrels or groundhogs know there is a big difference in wound size between a young one and an adult when shot with high velocity PB guns. Young groundhogs are practically blown in half when older adults have entrance and exit wounds. That shows me there is a difference in tissue density in the same animal with only age being different. 

 

[alamih]

Vadimas, what is this bullet in your picture ?

are you casting,if so what bullet moulds do you use ?

 

[ChuckHunter]

((Slug 35gr 935fps.

Tests were conducted during the hunt,the damage results are very similar,in hunting on small animals slug with a hole is useless.))

This is a 34 grain varmint knocker big hollow point .25 cal at about the same speed maybe a touch faster! Recovered from a woodchuck shot at 60 yards right between the shoulders standing on his hind legs.

The slug stopped just under the skin in his chest....I would say the hole in the slug is a little better than useless!!!

 

[Vadimas]

Vadimas, what is this bullet in your picture ?

are you casting,if so what bullet moulds do you use ?

The bullet is pressed

 

[Vadimas]

((Slug 35gr 935fps.

Tests were conducted during the hunt,the damage results are very similar,in hunting on small animals slug with a hole is useless.))

This is a 34 grain varmint knocker big hollow point .25 cal at about the same speed maybe a touch faster! Recovered from a woodchuck shot at 60 yards right between the shoulders standing on his hind legs.

The slug stopped just under the skin in his chest....I would say the hole in the slug is a little better than useless!!!

I can make bullets like yours with a hole,

but the little animal does not need it.

 

[Cranky1]

Okay I got out my chrony this morning and the mk2s are at 860fps avg and my 32.8 vk large hollow points are roughly 30-35fps slower. So I’m seeing a much larger exit hole on bird with lower a lower ftlb projectile. 

 

[ChuckHunter]

Okay I got out my chrony this morning and the mk2s are at 860fps avg and my 32.8 vk large hollow points are roughly 30-35fps slower. So I’m seeing a much larger exit hole on bird with lower a lower ftlb projectile.

The thing is that even if the slug is lower fpe at the muzzle it retains more energy down range. So say at 75 yards the slugs has increased energy over the pellets because it has such a good BC and doesn't slow down like a pellet does...that's why slugs are so good for longer range shooting. 

James from Michigan 

 

[AirgunBill]

I’d like to see a test using a small block of ballistic jell about 1 1/2” thick In a weight to replicate the thickness and weight of say a starling or squirrel rib cage. Set it up free standing so the jell moves upon impact just like an animal would. A sheet of Kevlar behind to catch the slug or pellet so you can see what expansion you truly are getting between the different types of projectiles. Then shoot them at 850 FPS and 950/1000 FPS and see if there is a significant difference. Shooting a big heavy block of Ballistic jell just doesn’t replicate actual conditions. As I stated in another thread full expansion happens within the first inch of impact. I also believe though there is a significant difference in tissue density between animals. So a bird would have different results when compared to say a squirrel. And of course bones would have a huge effect on the results. Birds have hollow soft bones when compared to mammals. Those who have shot ground squirrels or groundhogs know there is a big difference in wound size between a young one and an adult when shot with high velocity PB guns. Young groundhogs are practically blown in half when older adults have entrance and exit wounds. That shows me there is a difference in tissue density in the same animal with only age being different.

Leatherman in my video I did as you requested shooting a starling and pigeon equivalent weight block of ballistic gel to gauge actual expansion to be expected from the NSA slugs and JSB Hades I am just starting testing so more to come. I am with you as far as the difference between birds with little bone structure compared to other mammals to take into account. I plan to do more testing on actual birds and other critters I shoot out in the field to get more realistic results. Bill

 

[AirgunBill]

Okay guys one of main reasons for my testing is to get real world results from shooting various pellets and slugs at various sized critters. I want to know the ability of the projectile to expand and dump its energy into the target and or leave a larger more damaging wound channel on pass through. In recent tests and other tests I have seen in the past shooting full sized blocks of clay or ballistic gel weighing 10 pounds turned sideways is not a true representation of expansion for most of the small pests and game we shoot. The statement that most of the expansion occurs in the first two inches of penetration is not going to be the same on a 4 oz. starling and a 10 lb. pound block of ballistic gel. 

One of the game species I hunt is the wild eastern grey squirrel not the suburban one that are sitting ducks that people shoot off their bird feeders. In the woods these squirrels are wary, will not sit still a lot of times and for me most shots are in the 40 yard plus range. That means a head shot is not always available. I then go for chest shots which with .22 cal pellets and even hollow points with not anchor them in place. I have moved up to the .25 caliber and a chest shot with that means the don't get far. I want to do testing on ballistic blocks the weight and thickness of a grey squirrel and eventually on dead squirrels to see actual expansion with the JSB Hades and slugs. If I get get decent expansion then chest shots would become more viable.

So far I have just began shooting slugs this summer on pest birds like sparrows, starling and pigeons. The slugs are devastating on those birds but how much of that is just higher fpe and heavier projectiles as well as any major expansion. My initial tests show while there is minimal expansion you are not seeing the mushrooming or pancaking like in some videos. Now on larger critters like raccoons and groundhogs we are getting into heavier game with heavier bone structure. Up to now my practice with groundhogs is to go with head shots. Now with slugs maybe with better expansion we can go with chest shot if needed. I have shot a few thousand groundhogs with centerfire and rimfire and groundhogs pound for pound are one of the toughest critters out there. My experience shooting them with the .22 long rifle sometimes a chest shot will put them down and other times they run off. The .22 Long Rifle still is two to three times the fpe of many of the air rifles we shoot slugs. I am not sure how well .22 rimfire bullets expand unless hitting bone but with the new air rifle slugs and new FX Hybrid slug if we can get great expansion on groundhog sized critters that would maybe make chest shots more ethical. You would not have to anchor them in place but just like when you shoot a deer it can run a few yards before expiring that would be okay for me as a pest shooter for local farmers.

In the end I think what the industry is doing for us coming up with more improvements and innovation is fantastic. I am particularly impressed with FX as the owners being airgun shooters themselves really care about the sport. Their willingness to work with others in the field to innovate and give of more choices is to be applauded. Bill

 

[Long_Shot]

Nice test of small blocks of gel. you did there Bill.

That's the type of test that helps to approximate what happens to a small pest with a given slug/gun combo.

HP expansion is such a complicated thing to have it all work at POI . Pellet PCP's are just barely powerful enough to get most slugs to perform expansion wise. More FPE and velocity is a big plus (and almost required), but the right design is the key provided there's enough velocity at POI.

I probably spend more time testing HP's than I do shooting paper and such. I have video of cadavers, (Starlings and Ground Squirrels) that literally fly up 6+" into the air and fly back 12 - 18+" hit by the right slug, and just roll over with the wrong one. BIG difference! 

My experience in .25 cal. has been the right design HP opening and ogive at the right velocity and FPE can be very surprising. 

And the wrong one would do little more than a dome at POI. I've made HP's that don't work, and ones that do even at 200 yards. 

Keep up the testing.