The Age old velocity vs heavier bullet for solids on thick skinned game- Nice video illustration.

[Newboomer]

Heavy bullet. A couple hundred years ago, it was heavy lead bullets at slower speeds and proved devastating on most anything it hit. Think of the old Sharps buffalo rifles, 45-70 and other big bores. Even today most of your dg rifles are big bores throwing a big chunk of something at relative slow speeds. I'm a firm believer in heavy for caliber slugs.

 

[hawkeyesatx]

Heavy, long bullet for caliber, as stated above, of SD .30 or higher, along with what is considered moderate velocities today, of 2400 - 2600 fps, will dig deep and keep going.
Smaller, high velocity, bullets only work on thin skinned, non dangerous game animals.

Hawk

 

[Newboomer]

Heavy, long bullet for caliber, as stated above, of SD .30 or higher, along with what is considered moderate velocities today, of 2400 - 2600 fps, will dig deep and keep going.
Smaller, high velocity, bullets only work on thin skinned, non dangerous game animals.

Hawk

And they don't break bone like a big slug.

 

[Red Leg]

Sorry, poor attempt at a joke. I was implying that you would have to be ancient to have accumulated 125 years of experience.

I also think that the kids and his airgun agreed with science and the entire history of firearms including black powder and nitro based powders

1/ Increasing weight of projectile increases penetration in a more linear fashion.
2/ Increasing Velocity increases penetration but is more like the law of decreasing returns. Each incremental increase in velocity results in a smaller increase in penetration.

Sigh.

 

[BourbonTrail]

The 30x113mm has a muzzle velocity between a 30-06 and 300 Weatherby, with a 4200 grain projectile…it can penetrate a literal tank like a stick of butter. Maybe we should go with that, and then everyone can have a reason to complain about recoil.

In reality (aka physics) momentum is 2 part: mass and velocity.

Mass is directly tied to inertia, which is something’s ability to resist changes in it’s momentum (read velocity). The higher the mass, the better it is at resisting change…more momentum retained = better penetration. Bullet design is part of this in that it dictates how the mass interacts with its environment (read @michael458 ’s dissertations on this interaction in an aqueous environment). Interaction being the same, mass wins out. Velocity increase just increases your starting momentum, it doesn’t improve your ability to resist changes or the interaction with the environment.

This ends the lesson from your local Aerospace Engineer, now back to my Scotch.

 

[Tra3]

I think the same concepts apply to archery hunting, which is why I use very heavy arrows and broadheads. Slower speeds, but they shoot through animals and bone.

 

[Nhoro]

Only ibitially after a certain vel9city about 2400 and higher penetration actually starts decreasing.....in a proper DG caliber no idea in a pellet gun.....which is not relevant anyway....

Research super cavitation.....

Thanks IvW, I would agree that eventually the target material just cannot get out of the way and penetration reduces. I have researched super cavitation in great detail and I do not think it actually applies to bullet penetration. I did some maths and if supercavitation was true, bullets would have penetration in water measured in kilometres and not cm.

The US military have sponsored some research which has actually been published but it relates to military rounds ie spitzer boat tail and designed to tumble solids. It is an equation which defines each factor like velocity, weight, resistance of target. Then they use integration to solve .

Unfortunately, none of us have the resources to run hundreds of tests, each time varying just one parameter. And even if we did, it would only be valid for one calibre/one twist rate.

For example, just to test velocity effects, lets say you chose 10 shots at each velocity from 0- 2600 fps in 50 fps intervals in your 500 Jeff. You would need 520 shots to develop the graph for one parameter.

That is exactly why I enjoyed the fact that an enterprising kid tackled the impossible with an airgun and a few pellets.

 

[IvW]

Who would start at 0 zero velocity? What is the point of that?

Take whatever you have with whatever medium you prefer start at 2100 and work up to 2600 and let us know the results.....

I have done that.....anything over 2400 is a waste of time and only= more recoil and less performance.....

2150 to 2400 ideal 2300 right bullet you sorted simple as that......

Excluding pellet guns of course....

 

[mark-hunter]

No need to worry about, This forum stays in line, so far 100% opinons, rests on heavy and slow bullet, on the poll.

 

[ChrisG]

Well there is the physics, then the practicality. The bullets design has a lot more to do with what the velocity apogee is at which penetration begins to decrease. After all... a bullet made entirely from tungsten carbide and spun fast enough to stay nose on regardless of what it hits, will increase its penetration for each incremental increase in velocity. Using smokeless powder I don't think you would ever hit a point at which an increase in velocity decreased penetration with a bullet like that.

In real life, a bullet with a bonded core and tough steel jacket is going to reach that apex at a higher speed than one which deforms or rivets at a lower speed. for example:

a hornady DGS will penetrate better than the old hornady copper jacketed solids and will keep increasing penetration beyond the velocity where the old hornady's start decreasing their penetration.. for example (these are just numbers not real figures):

1800 fps
Hornady DGS: 42"
Old Hornady FMJ: 42"

2000fps
Hornady DGS: 46"
Old Hornady FMJ: 45"

2400fps
Hornady DGS: 49"
Old Hornady FMJ: 43"

At a certain point, a bullet will begin to deform and lose energy faster due to it presenting a larger frontal area to the tissue. Until it deforms or veers off course though, it will continue to penetrate deeper for an increase in velocity. So it will be different for each bullet design. If you could come up with a bullet that stayed nose on and never deformed. Pushing it faster would make it penetrate deeper indefinitely.

Otherwise, physics doesn't work and Isaac Newton is a liar