Can slugs be designed to have more subsonic effect

Much of the work done with .45 ACP Hollow Point and frangible slugs is applicable since they were generally in the near sonic subsonic range of velocities and muzzle energies similar to a .457 Texan. Look particularly at the ones intended to cause lots of trauma but not pass through harder objects such as walls!

I think you need to read this article and note the mentions of hydrostatic (mostly at supersonic impact velocities) and hydraulic (which is what happens at subsonic velocities we have)

https://www.ballisticstudies.com/Knowledgebase/Effective+Game+Killing.html

BOTH open temporary wound cavities, both disrupt tissue at the impact point. Hydrostatic is THEORIZED to shock the nervous system further away in the body but no one really knows

You may be operating under a misperception... What causes the cavity and the damage is not the denser air ahead of the bullet or cavitation but IS the transfer of momentum from the bullet to the tissue, accelerating the tissue outward where it stretches and tears in a 'shock wave'. Even a subsonic bullet accelerates the denser medium of liquid or flesh out of it's path in the collision.

Some bullets take advantage of this by increasing the outward amount of displaced material. An example is the nylon/copper dust injection molded non-expanding ARX bullet

https://www.inceptorammo.com/inceptor-product/component-bullets/

I have several boxes of the .357 ARX bullets and they shoot nicely in any of my .357 air Rifles and have worked quite nicely on hogs at under 50 yards ( not a long range bullet, it slows down too fast)

These below are solid copper and I'm not recommending them for Airgun use but showing them as an example of bullets designed to rechannel the tissue outward more violently and cause more disruption.

https://www.lehighdefense.com/all/355cal-9mm-xtreme-defense-90gr-bullet

The way a HP bullet works is that as the material enters the HP cavity it wedges to bullet nose further open. And as the diameter increases then more material is 'trapped' in front of the bullet and energy is transfered to that material, accelerating it while simultaneously that bullet slows down from the lost/ transfered energy. The tissue accelerates by X foot pounds and the bullets loses kinetic energy by the same X foot pounds. Since the tissue is traveling radially outward (and forwards) from the path of the bullet a cavity forms in the 'elastic' medium of the tissue or liquid (complicated by the incompressibility of liquids)

Since we are dealing with pneumatic guns, the realistic velocities are always going to be subsonic and usually well down from that in the 750 / 850 range. Non-magnum pistol velocities like .38 Spl or .45 ACP at best. So in reading the above article I would recommend relating everything to our low velocities and non-jacketed bullets. To me that means 'go big' in caliber to get the greatest hydraulic shock and to have a heavy enough bullet to punch through and make both an entrance AND exit hole for better blood loss. And I like a wide nosed bullet so even if it's velocity has dropped at a longer range the bigger meplat transfers more energy. Note that a HP that does not expand (because it slowed down), the cavity fills and the flow around the bullet simulates a solid 'flat' nose across the mouth, so there too the bigger the caliber the better. For deer and hogs I don't go under .357 just for that reason although others do.

Nation, 

I've been working on some homemade slugs in .1775 diameter for use in 12 ft lb Field Target guns. These projectiles are 15.04 grain hollowpoint, with a 2S nose shape, and a Flat base. I've gotten almost the results that I want, they look pretty promising. More testing when I won't freeze my buns off. Here's a quick video on my preliminary results. 

https://youtu.be/zSEG_QHVLjQ



Tom Holland 

Field Target Tech 

This is what we've been experimenting with and have gotten some amazing results.   Pretty much maximum energy transfer in small critters such as squirrels. Also a huge reduction in ricochets so much safer than standard slugs and they hit very hard. These have been the most devastating round I've seen out of a .22 or .25 airgun.

My friend and I started reloading and making our own projectiles in the 1960's. We shot every caliber we could get our hands on into every material we could find with every type of bullet we could buy or make and recovered as many projectiles as we could dig out. The amount of all manner of game and pests we harvested in the past 50 years is significant. For larger game (not birds and rats, etc) I second the above advice of larger caliber, big meplat on solid bullets with knowledgeable shot placement as key to consistent clean kills at the velocities we have to work with. The Taylor KO factor has some relevance here. In response to the OP question, bullets can be designed to maximize tissue damage but at low airgun velocities would likely compromise penetration if bone is encountered. For example, shot from my air rifle, I recovered a soft lead .45 RNFP slug that was travelling 800 fps at impact that was completely stopped by the spine on a medium size whitetail deer. The deer dropped in its tracks, but penetration was only about 2" with the slug not that badly deformed.

Willie, don't let my post discourage you from pursuing your quest. What you learn and discover can be worth the journey. Airgun's do not yet have optimized projectiles.

Will Piatt

I look at it like this. The airgun transfers energy into the projectile and sends it on its way. The projectile is charged with X amount of FPE and will lose some on its way to the target.

Upon arrival and or passing through, energy is then transfered into the target. I personally like to see every last foot pound dumped into my critters and not into the dirt behind them. Keep in mind I'm usually hammering smaller pests though. I am able to manipulate the slugs to open up less for more penetration if needed.

For the critters I'm after I like them to open up as fast as possible since they're only a couple inches deep. If the projectile doesn't exit, I would consider that maximum energy transfer and can't really imagine how to come up with more, but I've been wrong before.

Don't confuse the term shock in shooting with electricity. They are not related in this discussion!

"hydrostatic shock" from the data I read is a myth. Combat surgeons/researchers cannot even agree on it.

Put as big a hole through the game as possible in the best possible kill zone. As the saying goes "Bring enough gun"

God will take care of the rest.

The 'intentional tumbling to promote greater wounding' is is just another old wives tale that grew in the Vietnam War era. Yes, it's been repeated and repeated and repeated but it's simply not true. EVERY experiment with trying this adversely effected accuracy at longer ranges and if you look at the decades of development into better bullets for the 5.56 round it was all about reaching out farther. That's why bullet weight went up and the rifles twist rate became insanely fast... And the bullets became even tougher to be able to pass the test of penetrating a helmet at 600 then 800 yards. FACT, look it up in REAL research material that is available to any dedicated researcher in the Internet nowadays. A cartridge designed for close range jungle and street warfare simply was not good enough in open country long range warfare. Lots of us 'gun culture' (who are also military) people knew it but finally the 'gubberment idjits' had to acknowledge it after we went to war in the Sandbox. Witness now, after so long trying to make a silk purse out of a does ear, the 'new' official cartridge being adopted is of larger caliber shooting a heavier bullet. [Search "new us cartridge military 2019" or read this brief article https://www.military.com/daily-news/2019/10/27/inside-armys-quest-revolutionary-new-bullet.html/amp]

And even fired BACKWARDS (because I tried it as a curious reloader) FMJ don't expand much, the jackets are simply too thick by DESIGN so that they have a bit of barrier penitration ability (you could say they are intentionally mildly armor piercing and not be wrong).

I've done a LOT or reading on terminal ballistics, there are THOUSANDS of REAL scientific studies done by the US Army, the Alphabet org, medical doctors, bullet developers and just curious researchers. You need to go do a bit of research yourself (develop you Search-Fu) and then start working on developing and testing your theories because right now you are way off in left field. I have ALSO shot almost a thousand test shots into REAL ballistic gelatin myself (which used to be a LOT OF TROUBLE and EFFORT with the acquisition of the powder, making, refrigerating and transport of the gelatin to the range), not homemade test media like clay or wet newspaper so I have a bit of knowledge to base my opinions on. I've tested cast, paper patched, plastic jacketed, swaged dust, and all kinds of jacketed in multiple calibers so it's been pretty far ranging.

I am not saying you are wrong per say, but you need to do more reading on the subject.

FYI - It's out of stock right now because all the ones produced were sold out but here is my bullet I designed SPECIFICALLY for .357 air rifles that have enough power like Texans, Pitbulls and Slayers

http://noebulletmolds.com/NV/index.php?cPath=35_590

Designed to open up at airgun velocities and dump it's energy in the game (hogs and deer size mostly), have low bore friction and to be ACCURATE. I spent over $1300 on different custom molds as the design was tweaked to get what you see today, version 4 (I don't make any money on these molds, NOE just is offering my design)

Willie14228 - I'm glad you started this post. YES! The design of the HP is critical to the "effect". 

I don't care what label you want to put on the "AFFECT". Airguns can produce amazing results shooting a .25 cal. at only 940 FPS with the right design and enough FPE. 

Pure lead and no copper jacket. That's big at POI for expansion purposes if you have enough gun. I'm not talking stock pellet shooters here. 

Swish and I make our own slugs . His three way split design is extremely violent at POI compared to the same slug unsplit. 

I've made HP designs that sucked. Too small and or shallow of a point. POOR expansion. 

I feel the one I use now is ideal. Here's a photo of Hydraulic Affect? Maybe. Water won't compress so the can gets bent that bad 1 full inch away from the slugs path. I've wondered how much pressure that water is under to do that. Oh, that was at 175 or 200 yards by the way.