Seismic Ammo’s Extremely Heavy Projectiles in 9mm, .45 ACP, and 12 Gauge

[RecoilRob]

My cast 9mm load uses a 154 grain lead bullet over 3.8 WW231 for right around 950 fps out of a 4" barrel last time I clocked them. It shoots much 'softer' than even most 115's factory loaded but I think it's mostly the lack of muzzle blast and flash making that impression. Being as neither really punishes the hand the other things we perceive during shooting when they don't 'BARK' as loud they also feel 'softer', though the time impulse is likely a little slower with the heavier bullets so that might be playing a part too. Light carry guns sprung to run the 154's won't even eject 90 grains and are not reliable with 115's while they're totally reliable with the heavier bullets so there's something in the momentum impulse even if the delivered energies are similar.

 

[Walkalong]

Added to earlier post.

N340 Load:
Recoil Impulse .91 (lbs.sec)
Recoil Velocity 10.64 (fps)
Recoil Energy 4.84 (ft.lbf)

2400 Load:
Recoil Impulse 1.19 (lbs.sec)
Recoil Velocity 13.95 (fps)
Recoil Energy 8.32 (ft.lbf)

Since all recoil figures are larger including the recoil velocity for the 2400 load, I assume what I feel is the difference in acceleration.

 

[ATLDave]

Since all recoil figures are larger including the recoil velocity for the 2400 load, I assume what I feel is the difference in acceleration.

Not to quibble, but neither a Model 28 nor a Mk III has a slide and tilting barrel. I still suspect you are feeling something other than the pressure curve directly (perhaps something to do with blast), but at least you have a direct, rigid, steel connection between you and whatever is happening in the barrel. My certitude about the inability to feel pressure curves in a 1911 is based, in part, on the fact that there's a "suspension" that delays communicating anything happening in the barrel to the shooter until after the bullet is basically at the muzzle.

I think it is unlikely that a human can directly feel a pressure curve in a revolver, but I feel fairly certain that it is impossible in a browning-type gun.

 

[Walkalong]

 

[Goosey]

The ability of a projectile to penetrate and damage a target is dependent on its momentum.

p = mv

Guess their 9mm should hit like a 5.56

 

[Dudedog]

That's not what I am saying. What I am saying is that I do not believe that humans - any human - directly perceives the speed of powder in a way that would lead them to experience slower powders as being gentler and faster powders as harsher. I contend that cannot happen.

OK, won't argue but I can tell the difference between a 125gr 9mm bullet at 1050 using say AA2/HP38 and the same bullet at 1050 using WSF.

Different recoil impulse (area under curve) I don't know.
Same bullet, same vel, same ME but feel different to me in a 1911.

 

[mcb]

OK, won't argue but I can tell the difference between a 125gr 9mm bullet at 1050 using say AA2/HP38 and the same bullet at 1050 using WSF.

Different recoil impulse (area under curve) I don't know.
Same bullet, same vel, same ME but feel different to me in a 1911.

If it's the same bullet at the same velocity the area under the curves is the same. The shape might be different but the area has to be the same if both bullets have the same momentum. If you are perceiving a difference it is more likely you are seeing different muzzle flash or feel different muzzle blast and your body and mind integrated that into the recoil experience. That is felt recoil vs measured recoil.

 

[Walkalong]

If you are perceiving a difference it is more likely you are seeing different muzzle flash or feel different muzzle blast and your body and mind integrated that into the recoil experience. That is felt recoil vs measured recoil.

Nope, we can feel the difference.

 

[ATLDave]

Dude' and Walk',

You can feel something. Golfers also strongly "feel" the duration of club/ball contact (times which are longer than gunpowder combustion times), but actually do not. Their brains are integrating other sensory inputs into a strong sensation - but it is not measuring the actual input/event they believe it is measuring: https://www.researchgate.net/public...elation_with_the_perceptions_of_elite_golfers

Now, it's perfectly reasonable to tailor golf clubs or handloads to cater to this sensory integration feel. If a particular powder is more pleasant to shoot while generating similar or superior ballistics, then it hardly matters whether the shooter is actually feeling a different shape in the pressure curve or some other aspect of the powder's behavior. Just as it doesn't matter that the golf club "feels" softer just because of some sound-deadening material in the head, not because of actual hardness or flex, if the golfer likes a soft feel.

If you've never messed around with your brain's sensory integration circuitry, do this experiment. Go to the store and buy some scented-but-unsweetened soda water - say, strawberry-flavored. Bring it home, and pour a few ounces in a glass. If you've bought the correct kind, it will smell of strawberries (or some artificial approximation thereof). Taste it. It will have very little taste and, if you're not used to drinking this kind of beverage, it will be an odd sensation. It will taste about like ordinary carbonated water... surprising, given the smell. Now, stir in a little sweetener. Take another sip. Suddenly, the water has flavor. And it's not merely a sweetened-water flavor. Your brain will immediately integrate all the aroma inputs as taste. The water will now taste like strawberries, or at least like strawberry soda. It will not taste like sweet water that smells like strawberries - it will taste like strawberries.

Too many people chalk up others' ability to perceive things as "placebo" or "power of suggestion" stuff. That's not what I am doing. I have no doubt that you each are perceiving something, and that there is some real-world variation that is driving this perception. I just think (and for semi-autos, I feel like I pretty well know) that your brain is reading one phenomeon as another. Which is normal for human brains.

 

[Deus Machina]

Going back to automotive comparisons...
Of course you're going to feel it through something without a suspension (a revolver), and it's dulled by any suspension you do have (springs and a slide). But even though the tires are lifting the same distance, if you're paying attention you can tell the difference between going over speedbumps of varying widths versus going over a curb.

 

[ATLDave]

If the shocks/springs are as soft in relation to the car/tire as they are in relation to the frame/slide, all you can tell is the vertical velocity of the tire. Time spent traversing the front of the bump/curb is many, many, many times longer than the bullet time in the barrel. By the time the slide begins to communicate anything to the frame, the bullet is basically at the muzzle. All the slide can communicate is its own inertia.

 

[mcb]

Nope, we can feel the difference.

To put some more temporal numbers on it. That pressure curve AltDave posted back on page 2 for the 38 Super. The entire graph encompasses less than 1 msec of time. It takes more than an order of magnitude more time (10-20 msec) for that tactile input to get from your hand to your brain. The bullet has left the barrel long before your brain realizes your hand has experience a recoil event.

When you do a pressure test to generate the curves AltDave posted you have to sample that data very fast to actually generate the pressure vs time curve. At a 20kHz sample rate you would get less than 20 actual data points to plot that curve from. It was likely sampled at higher rates, IIRC SAAMI spec is to sample at 100kHz. To put that in perspective you have not been able to hear a 20kHz tone since you were probably 17-18 years old or younger. 20kHz is about the upper limit for young ears frequency range. The recoil event simply happens too fast for the human senses and human brain to resolve more than the integral (totality) of the event without the aid of a high speed data acquisition system.

 

[Walkalong]

I get that y'all don't get it, and that's OK, but you can't mimic a lot of things that other people in the world can do, nor can I, but that doesn't mean they cannot do it.

 

[mcb]

I get that y'all don't get it, and that's OK, but you can't mimic a lot of things that other people in the world can do, nor can I, but that doesn't mean they cannot do it.

What aren't we getting? Sure there are things only a small subset of the population can do/perceive but then there are things that are simply well beyond all human capability. At some point this comes down to the physics of how human senses work and the inherent limitation to those mechanisms. A recoil event is simply too fast for even our hearing let alone our other senses. Hearing is our fastest sense, with vision a distance second, tactile sense is the slowest of the five. I can fool your brain into thinking you are seeing smooth continuous motion at less than 100 hz (more than 10 recoil impulse could be strung together between two frames of standard 60Hz cable TV frame rate and yet your going to tell me your tactile sense has a higher temporal resolution than either your sight or your hearing? All the research I have read points to the fact this is beyond the resolution of human tactile sense. If you have a research paper you wish to share that shows otherwise feel free to share it. Baring that do the double blind study I mentioned earlier in the thread.

 

[Walkalong]

What aren't we getting?

That some folks can obviously feel the difference.

 

[ATLDave]

99% of people would swear they can taste strawberry. They can't. They can taste sweet and smell strawberry, and their brains can mix it together. From a practical perspective, they can taste strawberry... but from a physics perspective, there are no strawberry-flavor receptors in the mouth.

Nobody doubts that you are experiencing something. We just think it is impossible as a matter of physics and neuroscience for your brain to be directly measuring exactly what it tells you it is measuring.

 

[mcb]

That some folks can obviously feel the difference.

Obvious to some I guess, I have not meet any of those exceptionally perceptive people personally. Do you have any proof you can share in a forum friendly format? A link to good study, paper, or documented experiment or do we just have to take your word for it? This is not my first time studying recoil or human perception (in a previous job I work closely with the blind and their tactile senses). I think I have laid out some fairly sound science, push come to shove I can start populating the thread with reference to scientific papers discussion various human sensory performance and limitations to support the claims I have made in previous post. So far all you have done is to claim the opposite with zero reasoning, proof, or support for your claim. I would be happy to read and consider any information you can supply to support you claims but at this point you have offered nothing more than your unsupported claim and that makes for a very poor discussion of the topic. I have had my say on the subject and unless new analyzable information is presented I will respectfully bow out of this portion of the thread, no hard feelings, just no progress.

 

[Walkalong]

Do you have any proof you can share in a forum

I have already posted that neither side can prove what they are saying.

and unless new analyzable information is presented I will respectfully bow out of this portion of the thread, no hard feelings, just no progress.

Well, no progress is something we can both agree on.

 

[Walkalong]

And so it is a good time to close it.

If the OP wants to re-open the thread they can PM me and I will re-open it, as well as delete all the off topic back and forth between us. Despite intentions on both sides not to beat it to death again, we did. I'm even willing to take 100% credit for the OT postings.