Also with the first bullet, if you look just below the rear of the sight ramp, you can see where the jacket is bulged upwards above the line of the bore. This is caused by the way the barrel vibrates when the gun is fired. The front sight is heavy enough and high enough off the center line of the bore that it acts like the weight on a fishing line. When fired, the barrel expands slightly, twists slightly around the center of torque of a mathematical point related to bore, land, groove, barrel diameter and taper. In addition, it vibrates vertically (pitching). If you look at a fast enough video, the barrel makes a tiny ‘crack the whip’ kind of movement every time it’s fired. This is what barrel weights are used to mitigate on some target guns.

The extrusion of the bullet jacket on the first round is caused by the way the barrel bulged during one of the ‘crack the whip’ actions of one of the other rounds. Just guessing I’d say most of the damage was probably done by the fourthand fifth rounds. It wasn’t until the fourth round lodged in the barrel that the bore was occluded by enough compressed lead and jacket material that the propellant gasses bypassing the fifth round weren’t able to find a way past the previous bullets. That’s the reason for the gap between the fourth and fifth bullet.

To get a visual analog of the way the barrel acts when fired, take a look at a high pressure hose. While the material in the gun barrel is orders of magnitude stiffer and more resistant to deformation by the fluid inside it, we’re still stuck in a universe constrained by basic physics.

The bullets will also have moved from their ‘as fired’ position in the bore during the cutting process to show the cross section. The fifth bullet didn’t pressure weld itself to the fourth because of the compression issues and as such probably moved significantly more than the others did during the cutting.

If you look at the enlarged picture, you can see a series of discolored, angled marks in the metal of the barrel. These are just above a point about 1/3 the length of each bullet forward of its base and angle back towards the breach and up towards the topstrap. These discolorations are caused by the barrel bulging with each round.. They’re the result of changes in the metallurgy of the barrel as it was bulged and ‘whip cracked’ with each round.

You can find all of the necessary math and material values in a good metallurgy text or in one of the high end machinist guides.

there’s plenty of barrel bulge to account for that bullet being moved back by the hardcore cutting that was soon to follow.

IMO of course

-advocate

…with that flat base pin and pinned front sight, it’s def .357 or possibly .44, the angle of the cut just throws off the look of the round.

.38 special semi jacketed waddcutters would be my bet. I’ve fired some old light loads that i could tell were squibs (just to clean out an old box), but had it been in competition, i could MAYBE, MAYBE see something like this happening for a second shot…. but not 4 times

With what looks like wadcutters, he may have been reloading target rounds.

When I reloaded (way back in the ’70s) a popular .38 Special reload was about 3 (THREE) grains of Bullseye Pistol Powder. That amount took up space about the size of an aspirin tablet, and was not easily noticeable in a .38 Special case.

If you’re too casual about this, it’s not that difficult to fail to notice that the case you are seating a bullet in has no powder and will only have the power of the primer to launch the bullet into the barrel and lodge there.

A subsequent round (WITH powder) could then move it, and itself, down the barrel, but not emerge. Further rounds would only compound the problem.

I’m surprised he didn’t notice a difference in sound. Does the gas escaping from between the cylinder and the back of the barrel make enough noise that a difference would be unnoticeable? (Probably so, if on a range with other firing going on.)

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I strongly doubt it; the front sight appears to be high enough to compensate for the recoil from the mass of a larger bullet than a typical .22 round. .38/.357 seems about right. They look like wadcutters.

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As far as the spaces, there may have been enough lubricity while hot to let the trapped air pressure between the rounds push it back a bit.

As far as seeing the bulge in the photo, you can see it in two subtle clues; first is the slight arch in the bore between shots four and five, and the second is the reflection of the overhead fluorescent light in the barrel surface behind the cut (towards the frame). The major reflection is too blown by the camera sensor to be useful, but the secondary reflections have an undeniable wave to them.

I’ve no idea why anyone would grind away a barrel like that!?