What curiosity got the cat

One of the surgeons working on the wounded of the Marathon bombing told the media that they were removing "ball bearings...2mm to 3mm diameter" from many of the wounded. Since curiosity isn't the strong suit of contemporary media, especially of the broadcast variety, "ball bearing" became the trope of choice to describe one of the ingredients in these two nasty bombs.

However, I'm afflicted with both curiosity and skepticism. I'm also a recreational cyclist trying to keep machines over 20 years old on the road. As a result I know something about the bearing market. In which it is damn hard to find loose ball bearings of any size; caged and roller bearings have been the norm for most of the 20-odd years since my bikes were built. It's especially hard to find small ones of steel. The few that are out there are ceramic, not steel. Bulk steel ball bearings fall more in the line of antique dealers than mechanics.

A reasonable person should not expect ER surgeons to be up to speed on such mechanical detail. They have enough to do to keep up with their own mechanics. Therefore a reasonable person paid to ask questions might ask if these pellets were truly ball bearings. That reasonable person would notice that while loose steel ball bearings have become scarce over the past 20 years, steel birdshot has become common, relatively cheap, and easily purchased in bulk. (This happened when the use of lead shot on waterfowl was proscribed for environmental reasons.) Because many hunters reload their own ammunition, the component parts of a shotgun shell are widely available. 

The projectiles described by this ER surgeon fit the description of #4, #5 or #6 birdshot, available in steel for $15-$20 for a 10 pound bag. That's not much more expensive per pound than the nails also used in the bombs. Depending on the variety, the gunpowder used in these devices is around $15-$20 per pound and available from the same sources in lots ranging (in my search) up to eight pounds: to anybody. Eight pounds is a lot of gunpowder.

My curiosity stops short of trying to search for the purported bomb-making sites: instinct says this is not the time to go prowling around them, so I don't know exactly how much of each ingredient they are supposed to hold. The component figures raise a point. A large part of the "evidence" advanced by talking heads is that these two putzes could not possibly afford the components; therefore they must have had external support. The same sources point to "no visible means of support."

Pardon me, but they had family and one had a wife. They may have been supported by family and one hopes the police will investigate that, even if it doesn't occur to pundits with an ax to grind. Two young men, supported by families, spreading out their purchases, could certainly afford a bomb's raw materials at these prices.

Washington Republicans and the gun lobby are trying to use the bombing as a way to reinforce their argument that stiffer gun laws won't prevent tragedies. Well, if two of the principal components of the bombs are available in bulk to recreational firearms users, then this event most certainly crosses into territory in which reasonable regulation would make a wicked big difference.  Sensible gun control also means bomb control.