January 04, 2011
By Allan Jones
By Allan Jones
You can learn a lot from recovered bullets. Fired from a .455 Webley Mk VI, these show there is enough cylinder misalignment to pull some bullet noses off-center (right). Consequently, the revolver produces poor accuracy.
Somewhere deep inside me, there has always been a fascination with the before-and-after nature of physical events. Accident reconstruction and similar disciplines compel you to recreate the "before" condition by looking at the "after" evidence. Working in a crime lab where catching bullets was a key function of the job meant I could reconstruct scenarios and look at a lot of fired bullets.
I'd been there only a short time when I first used the bullet recovery box to help me answer a burning question about one of my guns. I'd traded for a new Colt Trooper Mk III .357 Magnum not too long before landing the lab job in 1971. Unlike the other .357 revolver I'd traded off to get the Trooper, it showed a finicky nature in its dietary preferences. Whether factory ammo or handloads, I felt I was always on a quest to find the consistently accurate load for that revolver. One of my buddies suggested there might be some defect in the bore that could show up on a fired bullet. Why not catch a bullet or three, since I had access to the equipment?
So I did, using the old cotton recovery box. The fired bullets showed no bore defects but clearly exhibited signs of sliding into the barrel. The cylinder and barrel did not align properly. There was a light shear mark running up the nose on one side of the bullet.
This discovery made me think that investing more time searching for accurate loads was a waste of resources. Fortunately, I found someone who thought 4-inch groups at 25 yards was far better than he could shoot. He had a very clean 1933-vintage Colt New Service in .38 Special that tickled my fancy, so we traded.
After that, I was quick to use a recovered bullet to check for barrel or barrel/cylinder problems.
Another helpful aspect of recovering bullets helped me in developing cast-bullet loads. It didn't take long to figure out that some cast bullets showed evidence of gas cutting. Instead of producing the normal lead-on-steel contact, gas cutting would erode shallow, irregular channels up the bearing surface that looked completely different than surface melting due to excessive velocity. I also found out that barrel leading could have nothing to do with lead alloys or improper powder selection.
My first 9x19mm pistol was a Browning Hi-Power, and being the cast-bullet nut that I am, I was determined to use them in the Browning. I bought some hard-cast bullets from a local caster known for his quality work and strong alloys. I loaded up some, and the first four shots went into the water trap. That was an eye-opener.
There were no rifling marks left on the bullets; the gas-cut channels were so pervasive that they occupied the entire bearing surface. The bullet alloy was strong; the propellant was one with a low flame temperature. Everything should have worked on the first try. The Hi-Power's barrel showed where the lead had gone. The bore looked like a hole dug in dirt. After finally de-leading the barrel, I checked the only other thing I could think of: barrel diameter.
Some misalignment is normal for revolvers. Bullets from a .44 Special Colt New Service Target showed a slight misalignment from what is seen (right edge of each bullet), but it was not enough to keep the old revolver from shooting 6-inch groups at 100 yards.
That told it all. The cast bullets were sized 0.355 inch, always considered to be the proper diameter for the 9mm Luger. However, the Hi-Power barrel slugged 0.357 inch. Amazed, I started checking the groove diameter of most of the 9mm pistols in the lab's reference collection. Most were 0.356 to nearly 0.358 inch. The gas had a thousandth of an inch on each side of the bullet to escape and foul my Hi-Power's shiny bore. After that, I made sure I assembled only a handful of new cast-bullet loads and shot them into the water tank before loading up a bunch.
One of the most unexpected findings answered by a caught bullet started when I finally found time to completely tear down my 1918-vintage Winchester 1892 rifle in .32-20 WCF. Viewed from the front, the rifle had a sweet bore, but years of bullet lube, gun grease, and debris made its action drag. I got out the tear-down instructions and proceeded to remove and clean every little part that Winchester had mounted in the action.
With the action stripped, I had my first opportunity to get a clear view of the chamber and throat area. About an inch ahead of the chamber was a bulge. It was not big but was still a cause of concern; I'd paid good money for this rifle. I'd yet to get the rifle to a proper range to see what it could do, but knowing there was an "ouch" in the bore made my spirits sink.
I knew from test-firing evidence guns with barrel bulges that recovered bullets showed double rifling marks. The bullet disengaged from the rifling at the bulge and reacquired it past the defect. After getting the Model '92 reassembled, I fired it into the lab's water tank using a factory jacketed bullet load--I knew any skipping across a bulge showed better on jacketed bullets.
To my relief, the recovered bullet showed only one set of rifling marks. I decided that two factors were at play: The bulge wasn't terribly deep, and the defect was so close to the chamber that the bullet velocity was still rather low at that point. Still, only range testing would tell the true story. It turns out that the old rifle can shoot close to "one minute of prairie dog" well beyond 100 yards with either jacketed or hard-cast bullets.
"Don't Try This At Home!"
Realistically, catching bullets can be downright dangerous if not properly done. The line in the Firearms Safety Rules, "Be sure of your backstop and what is beyond," is strongly at issue here. Theoretically, the recovery device should be the backstop, but you must plan for the unexpected: a bullet that misses or completely penetrates the device.
For practical purposes, catching bullets is best limited to handguns and maybe those rifles chambered for handgun cartridges like the .32-20. High-velocity hunting rifles posed a problem even in the lab; we routinely downloaded them before test-firing into the water recovery tank. They still dropped so much energy into the water that the tank sprayed water, and the tank's walls were close to their flex limits.
We never fired centerfire rifles into the old cotton box. Rifle bullets showed a nasty habit of changing direction in the cotton and exiting the side of the box. That's a little more excitement than anyone needed. So, never try this with centerfire rifles producing more than about 1,400 fps.
This is by no means a basement project. Any recovery firing must be done at an approved range facility with the blessings of the range safety officer. His word is gospel for that facility, and there may be no arguments.
For outdoor recovery, a horizontal type of water box that contains 1-gallon milk jugs full of water works well. Using a gallon plastic milk jug as a guide, build a wooden trough about 4 feet long that's just wide and tall enough to hold the milk jugs side by side. Use 2x4 wood framing stock for the walls and floor; you must be able to control a bullet that changes direction in the water. Close off one end with about 4 to 6 inches of extra lumber to resist bullets that might make it through all your water jugs. Unless you plan to shoot prone, you may want to make some detachable legs to raise the box to normal shooting height.
You also need to make a top that lays over the trough once water-filled jugs are placed inside. A piece of 1-inch plywood will nicely deflect any bullet escaping the top of a jug. Some people building such boxes drill a few 1-inch holes in the bottom for drains; some of those cartons are going to leak a lot of water. Trial and error will give you an idea of how many jugs to use, but I would not start with less than four for the .38 Special with nonexpanding bullets.
Once you have the jug holder built and are at the range standing next to a happy range safety officer, position the rig as close to the backstop as possible. Use a rest to make sure the bullet goes close to the center of the box's open end and would otherwise impact the center of the back end. A misdirected bullet that strikes the edge of a board can bounce unpredictably. Flatnose bullets will travel the straightest, meaning less chance of finding a hole in the sides of the trough. Expanding bullets will stop shorter that nonexpanding ones, and they seem to move in a straight path before stopping.
I didn't say this was going to be easy. You'll need to save up lots of empty milk jugs, and you may have to pack water to the range. The box will be heavy, and you'll need a buddy to help you tote it out of the truck. And you will get wet.
Still, it's the safest way. I know guys who welded two 55-gallon steel drums end to end to make a water trap only to find that some bullets shoot out the bottom and go who knows where.
People have also thought, "Gee, my bother's swimming pool looks a lot like a crime lab's water tank on steroids!" They soon notice little holes in the pool liner, and Thanksgiving dinner with the family is a bit more strained.
Reading Recovered Bullets
So once you have recovered some bullets, what can they tell you?
If it's an expanding bullet, you have a good preview of how the bullet would work in gelatin. By noting the number of jugs penetrated, you can compare penetration between bullet styles.
If you use the bullets to check for a revolver's condition, the first thing to look for is cylinder alignment. A factory lead roundnose bullet shows misalignment best, but you can tell from other bullet types. If the bullet has a crimping cannelure or lube groove, see if it's the same width and depth around the bullet's surface. A little misalignment is normal; what you don't want to see is deformation. If the bullet sits crooked when stood on its base, the cylinder alignment is probably pretty bad. Jacketed bullets may show a "pulled base," which is a little flange of jacket that extends past the bullet base on one side.
Checking cast bullets for gas cutting is pretty easy, but mild magnification by something like a hand lens can help. Gas cutting shows up as channels with a lumpy surface. If the cutting goes more that two-thirds of the way up the bearing surface, it could give you trouble.
If you suspect a bore defect, you may need more magnification; a defect that's huge to the bullet encountering it is still pretty small to the unaided eye. Our lab used 8X to 10X magnification to look for bore defects.
Yes, you can catch a bullet and learn from it, but I must remind you: Put safety above everything else. If that little voice inside you says your set-up might leave something to be desired, back off! Believe me when I say crime labs went through a lot of trial and error over many years to safely stop bullets in good condition.