In case you ever wondered why, when shooting steel plates, bullet jackets sometimes come back but not the core of the bullet. Here, at 1,000,000 frames per second, is an explanation. Awesome video:
Via email from Erick P. at work.
The View From North Central Idaho
Ramblings on explosives, guns, politics, and sex by a redneck Idaho farm boy who became a software engineer living near Seattle.
Fascinating video. I found it interesting that the rifle bullets appeared to separate along the lines left by the rifling on the (presumably copper) jacket when hitting the steel. Does this mean that the pre-scribed lines on some hollow-points are there just for appearance, and do those types separate along the rifling too?
Did you notice that the expanding bullet types are fully expanded in just a fraction of an inch into the ballistic gel? Look closely at the shots that have clear views of expanding bullets, even the rifle bullets are fully expanded before the bullet has traveled as much as a full bullet length into the target.
Naw; that must be fake. I’ve seen in the movies that bullets bounce off of hard surfaces exactly like billiard balls.
Blackwing; on some pistol hollowpoints the “petals” aren’t merely scribed. They are almost entirely pre-separated in the forming process, like a pre-cut cheesecake with only the crust holding the pieces together, and then the tip is swaged down into its tapered shape. That makes them open up far easier at the much lower velocities of typical handgun rounds. The rifle round jackets are shearing at the rifling corners just because that is where the force is focusing as the jacket is being stretched apart. That and maybe because it’s a distinct border between more work hardened and not-so-work hardened zones in the copper. What would work well (expand and hold together) at pistol velocity would detonate at typical rifle velocity. Some of the light .223 Rem “varmint grenade” bullets do just that– they’ll blow a ground squirrel to pieces, but wouldn’t penetrate enough on larger critters.
SPQR; Max Q (maximum pressure on the bullet) is shortly after initial contact, so it makes sense that the tip begins to expand almost immediately. Once it slows down quite a bit, further deformation becomes almost nil on a rifle bullet. The much slower rounds from my muzzleloader for example, even though they’re pure soft lead with no jacket, don’t deform hardly at all in soft tissue. I recovered one ball after 25″ of penetration through a deer, and it’s in such good shape I bet I could load it and fire it again. So anyway; bullet terminal performance is all about the operating velocity, so they have to be designed accordingly.
Just some comments:
At about minute 8 they started shooting something very hard. The rifle bullets were not even denting it. Would like to know what that is.
There was much more “dust” than I would have expected. I assume it is mostly the lead core that is exploding into such minute particles. Now I can understand some of the lead poisoning concerns at at indoor range.
Notice the conical base on some of the rifle bullets used. It wasn’t a boat tail it was a cone. I have never seen a base like that unless it was a shape formed during firing, but I don’t see how the forces would function to give such a shape.
Anyhow, interesting, I will probably watch a few more times.
Curious, at about 2:00 they start shooting what appears to be molten lead at the bullets. Any ideas what they were trying to demonstrate? I went on their website but didnt find anything that explained it.
Ron, on their website there is a video section. One of the videos has a close view of the conical based bullets, they look machined/spun. FWIW, they describe them as 7mm hunting bullets. There is also a 3d video, but you need 3d glasses.
Lyle, the nearly instantaneous expansion of bullets fascinated me when I first learned it a couple of years ago because before high speed photography, the intuitive understand of rifle bullet expansion was that it happened throughout the path of travel through the game animal. Think how often you’ve heard claims that XYZ bullet expanded “too fast”.