These should not be confused with “less lethal” or riot-control projectiles. Rather, these are reusable primer-powered training bullets. I tested both .38 and .44 caliber versions.

Because they are powered only be a primer X-rings carry very little energy: They certainly will not cycle an auto-loading action. But they function seamlessly in revolvers when correctly loaded: In order to prevent the detonating primer from jamming itself against a revolver’s breech face it is necessary to drill out the primer pocket’s flash hole to 7/16″ on .38 brass and 1/8″ on .44 or .45 brass. (Note that with these expanded flash holes that brass should never again be used with standard loads, so it’s important to mark and segregate brass for use with X-rings.)

Loading X-ring ammunition is simple: seat a primer, then push a bullet into the neck of the case by hand. The average .38 X-ring bullet weighs 7.7gr, and the average .44 X-ring weights 14gr. I tested the .38s out of my 2″ S&W 642 revolver and the .44s out of my 3″ S&W 629. Longer barrels will only decrease muzzle velocity since primers produce so little propellant gas.

On the .38 I tested both WSP and CCI 550 “Magnum” primers and didn’t detect any significant difference in velocity. On the .44 I used WLP primers. I measured the average velocity for each load at 5, 15, and 21 feet:

Obviously these are not ballistically efficient projectiles. At these ranges they are as accurate as conventional ammunition, but even at 7 yards their point of impact has dropped almost a full foot due to their low velocity, which is decreasing so rapidly I don’t think they would be useful at much greater distances.

The great thing is that because they are so light the bullets will stop inside a cardboard box with a towel draped in the middle. They are reusable — the manufacturer claims that if they’re cleaned with silicone lubricant they are good for 75-100 firings. I didn’t see any degradation after shooting them five times. I noted that the first bullet through a clean barrel leaves a thin stripe of rubber against any sharp rifling, and that seems to buffer subsequent shots against wear.

It’s easy to clean a gun after shooting these: Any rubber peals away from the barrel with a single pass of a dry brush. However I was surprised at how dirty primers are: In the photo above you can see the fired nickel-plated case coated in a layer of soot, which also ends up in all the usual places on the gun. Immediately after testing I was able to wipe off all the fouling with a dry rag.

If you’re using conventional (lead styphnate) primers I would hesitate to shoot them in unventilated indoor spaces because this lead-laced fouling doesn’t all settle on the gun: It’s dispersed in the air, and it’s not good for you, especially if it accumulates in an enclosed space.

Finally a note of caution: These look like a tempting tool for close-quarters force-on-force training. Their impact energy is in the same league as a paintball, Simunition, or heavy air-soft pellet, which means that with adequate clothing and head protection these should in principle be safe to shoot at a real person. However, unlike those other projectiles X-rings fire from unmodified guns that are fully capable of shooting full-power ammunition. No matter how careful you are eventually a standard round will slip into a gun somebody thinks is loaded only with X-rings. Therefore, I would never fire these at a person, and I would always ensure my practice backstop can safely contain a real bullet.

To produce good ballistics a bullet needs several characteristics.

1. Internal: It has to remain solid at the temperature and pressures of firing, to avoid melting in the gun. It also must be softer than the barrel through which it is fired so that it conforms to the rifling of the barrel (which is critical to ballistic stability) and so that the barrel can be shot repeatedly without degrading.
2. External: It should be as dense as possible, since density not only increases stability but also reduces the energy lost to air resistance during flight.
3. Terminal: It needs to be tailored for some terminal objective. Depending on the target, we may want a bullet to explode, expand, penetrate, stop, or do some combination of those things.

Following is a list of elements that are of interest in meeting these objectives, ordered by density and noting their rough current cost:

References:

• Abundance of elements in Earth’s crust
• Elements by Density
• Precious metal prices
• The Metal Bulletin

Internal ballistics: Not too hard, not too soft

Lead, being a very cheap and dense metal, was the starting point for bullets. In order to harden it and make it easier to cast, lead is typically alloyed with up to 20% antimony and 10% tin. In higher-pressure modern rifles it is often necessary to crimp a thin copper “gas check” to the back of the bullet to prevent its base from melting or vaporizing in the barrel.

As bullets are driven faster and harder it becomes necessary not only to shield the base with copper, but also to surround the sides that engage a barrel’s rifling with copper. Typical copper jackets are composed of brass or “gilding metal” — alloys containing a small amount of zinc. Brass has a higher melting point and lower coefficient of friction than lead, so it reduces metal build-up and wear in barrels. With a copper jacket the bullet’s lead core can be reduced to relatively pure, dense, and inexpensive lead. These benefits have made copper-jacketed, lead-core bullets the standard for modern firearms.

External ballistics: Looking for an edge in Density

Long-range shooters obsess over the ballistic coefficients of bullets. The higher the ballistic coefficient the less a bullet is slowed by air resistance and the further its effective range. Given a gun and bullet of a particular size, you can first increase ballistic coefficient by streamlining bullet shape. But after that the only way you can improve external ballistics is by increasing the bullet’s density.

Included in the table above are the densest seven elements that are not dangerously radioactive. (Uranium 238, known as “depleted uranium,” is the isotope we consider here. It is radioactive, but its half-life is so long that it is not considered a radiation hazard. Its toxicity is similar to lead.) The next-most-dense metal, tantalum, is less than 50% denser than lead, and hence not worth considering. Unfortunately most of these densest metals are also among the rarest, as you can see by their cost. We’re not much more likely to see people shooting osmium-core bullets than gold-core bullets, even though at twice the density of lead osmium would double the ballistic coefficient!

Two of the densest metals are available at prices that don’t immediately disqualify them from consideration: Uranium and tungsten. These days people will pay as much as half a dollar for a match-grade lead-core target bullet, or a dollar for a premium hunting bullet. It’s plausible that they will pay a few multiples of that for a bullet that’s significantly more dense. But each of these two metals has some quirks beyond cost that limit their availability in ammunition.

Tungsten is extremely difficult to work in solid form. It has a very high melting point and is both very abrasive and very brittle. Solid alloys have been used to produce armor-piercing bullets, but their density is reduced to no more than 15g/cc while their manufacturing costs far exceed those of comparable uranium penetrators. Pressed tungsten powder cores are much easier to produce, and are used in a few frangible bullets currently on the market. But powder metallurgy keeps their density under 12g/cc — not much better than lead bullets.

Depleted uranium is soft and melts at low temperatures. In fact it behaves similarly to lead with one key exception: Its affinity for oxidizing (i.e., burning). So long as it is done in an atmosphere purged of oxygen it can be easily cast into bullet cores. After jacketing a uranium-core bullet is as safe to handle and shoot as a lead-core bullet. In practice uranium offers the only practical and cost-effective means of improving on the density of lead bullets: Finished uranium-core bullets can be up to 70% denser.

Terminal ballistics

Uranium cores have some unique terminal applications. Since uranium is pyrophoric uranium-core bullets tend to be incendiary. Pure uranium is malleable, but when alloyed with small amounts of titanium it becomes very hard, and even develops a “self-sharpening” tendency to fragment into shards that makes it an ideal penetrator. Given these characteristics it’s no wonder militaries have adopted uranium penetrators for anti-armor projectiles.

Conventional incendiary bullets are created by supplementing the core with titanium, zirconium, or other similar metals that oxidize easily and burn hotly. The thin jacket ruptures on impact with a target and the heat of impact is enough to ignite incendiary payloads.

In general a bullet’s ultimate goal is to deliver energy to a target, and as we already established denser bullets do this more efficiently. Exactly how the bullet dumps its kinetic energy into a target is a subject of many debates and a plethora of designs. Hunting bullets are tailored to do everything from fragmenting immediately on impact to expanding to a controlled size and then penetrating as deeply as possible without breaking up.

It has been more than a year since Casio began shipping the EX-F1, and it is still the fastest consumer video camera on the market. However, at its top speed of 1200 frames per second it only captures a very coarse 336 x 96 resolution.

Memory bandwidth and data buffering have previously been the bottleneck of high-speed video. Pros pay tens of thousands of dollars for specialty camera systems capable of capturing high-resolution video up to 10,000fps. (Higher frame rates require lighting power that would be beyond the means of amateurs.) But now that high-capacity solid-state data drives with write speeds over 500MB/sec are shipping for just a few hundred dollars the technology exists to produce a sub-$1000 consumer video camera that can capture full-resolution video at thousands of frames per second. I can’t wait to get my hands on one.

Better Console Gaming Controllers

Ten years ago Microsoft introduced a radical new gaming controller under its Sidewinder line called the Dual Strike. Apparently nine years ago they took it out of production. I used it to play several PC versions of Grand Theft Auto and liked the controller so much that when I discovered it was discontinued I scooped up a few more boxes at clearance. The Dual Strike is the best first-person shooter (“FPS”) controller I have ever used: It combines the precision and speed of a mouse with the convenience of a single hand-held gamepad that doesn’t tie you to a flat surface.

I recently picked up a PS3 and was excited to check out the state-of-the-art in FPS games. What I can’t believe is how bad the standard console controllers are for this purpose. Apparently people who are serious about these games buy split controllers like the FragFX which basically put you back at a desk with a mouse. Not exactly the setup one is looking for when plugging a console into a home theater system and sitting back on a sofa.

Though stockpiles of Dual Strike controllers are still available they are not compatible with the current crop of gaming consoles. I hope it’s not long before the console gaming complex rolls out a FPS controller to meet this need.

Computerized Ballistic Optics

Given how cheap and compact computer power is I can’t understand why the $1500 Barrett BORS is the only integrated ballistic computer on the market. Of course a professional shooter can do ballistics in his head for any shot one could take with a man-portable firearm (i.e., up to .50BMG shooting up to 1.5 miles). And serious amateurs cobble together their own ballistic computers, typically using a combination of smart-phone ballistics applications, Kestrel weather meters, laser rangefinders, and perhaps some angle gauges. Hopefully this is the year that scope or laser rangefinder manufacturers begin to integrate atmosphere and angle sensors along with ballistic data to provide precise firing solutions, perhaps even automatically adjusting the scope’s reticle for a particular shot. Before long I also hope to see laser rangefinders that integrate laser doppler anemometers to determine average windspeed and direction over the ballistic trajectory, making first-shot hits as precise as the rifle and the shooter’s trigger finger.

Bullpup Single and Double Rifles

As a fan of bullpup firearms I was excited by Steinkamp’s SW1 double rifle. But since their pricing is over the top I’m hoping that this year some domestic manufacturers will pick up on the concept to produce single or double bullpup rifles and shotguns.

Subsonic .22LR Ammunition and Barrels

As I wrote late last year, there are significant benefits to be had with heavier subsonic .22LR ammunition. I hope ammunition manufacturers step up their offerings of .22LR over 40 grains, and that .22LR barrel manufacturers switch to the higher twist-rates needed to shoot the stuff well.