Not enough columns on the spreadsheet

The potential new shooter I mentioned yesterday actually came through. It is a friend of Ry’s daughter Arden. So today Ry and I took Arden and Megan for a small private Boomershoot party.

The new shooter aspect went very well. Once she figured out a couple things with the first magazine she nailed three clay targets in a row from about 40 feet away then started nailing the steel swinger target we had set up. That was with a suppressed .22 LR with a red-dot scope. She probably went through 30 or 40 rounds with my iron sighted Ruger Mark II as well. She fired a couple magazines from the AK (and took the USPSA target home) . She went through another magazine with the AR-15, two rounds from the 12-gauge Saiga (she said she really liked it but the recoil was a little more than what was comfortable), and about 15 rounds from my STI in .40 S&W.

On the Boomershoot side we tried a new packaging method. We put the Boomerite directly into the cardboard boxes then wrapped them in Saran Wrap for protection from air and moisture. The packaging didn’t go as smoothly/quickly as I had hoped but I think with the proper equipment it could work. We didn’t bother to make up any of the old style targets with the Boomerite in a zip-lock bag and putting the bag inside the cardboard box. What could go wrong?

Megan hit her target on the first shot and it went off with a boom that wasn’t much more than the muzzle blast from a shotgun. Hmmm… almost a dud. Well, the others will probably be better. They were all worse. Some of them just barely popped and blew off a corner of the box.

Ry’s guess was that we had messed up the mix some way or another. Perhaps the batteries were bad on one of the scales (which we didn’t bother to check the calibration on). I wasn’t so sure. The mix looked normal to me. I’ve seen many thousands of pounds of the stuff and I can usually tell when something isn’t quite right just from looking at it.

Ry then did a very “Ry thing” (he has an extremely powerful CPU but it’s running a buggy software). He asked me to put some of the spilled Boomerite in a position where he could shoot directly at the cup or so that was in a corner of a box without going through the Saran Wrap or the cardboard box. I figured he would do this from 10 yards away or so. Nope, he walked up and got far more than “Entertainingly Close”. I’m not going to say how close but I will say that I was evaluating the ground near where he was shooting to make sure I could get my vehicle in there to roll the remaining body parts into the back and haul them to the hospital. The cup or so of Boomerite detonated with the normal BOOM! we all know and love. Ry still had all his limbs attached but he said his head hurt. He asked if the left side of his face was bleeding. It was red but not bleeding. He did have what looked a lot like a zit on his forehead that was bleeding slightly.

What we concluded from this admittedly small sample is that the packaging made a difference. How having a few layers of Saran Wrap on the outside of the box instead a zip-lock bag on the inside of box makes such a big difference is something we don’t understand. More tests are needed to confirm the results and that the old packaging works as expected with the same batches of material used with the new packaging methods. Assuming the weather cooperates I’ll do that next weekend.

As we have said many, many times before, “We don’t have enough columns on our spreadsheet to model this behavior correctly”.


8 thoughts on “Not enough columns on the spreadsheet

  1. I don’t really understand the ins and outs of it, so this may be colossally stupid. As I understand with reloading, case pressure is a function of (all other things being equal) the amount of air left after the bullet is seated. Could it be something like the bags leave a different amount of air than the saran wrap resulting in different burn rates?

  2. Purest 5 star Speculation:Saran Wrap outside the box-plastic drag-in provides initial lubrication/cushioning, plus the material inside is free to move about the box, reducing confinement during initiation. With the formulation in a baggie, any cushioning effect is counteracted by the confinement of the baggie. I recall that you said things worked best when the formulation was in a fluffy, low density state, so it might be especially sensitive to variations in confinement that might not appear critical. Maybe see if a “card wad” inside the box has any effect?

  3. Joe, I’m probably wrong but I think the difference that you experienced has to do with the density of the material and the difference between deflagration and detonation. The effect of the projectile on more loosely packed material vs. more tightly packed material may significantly alter the dynamics of the interaction.

  4. @Dee, Thanks for the concern.

    The recipe for Boomerite includes a strong anti-static component which gets all over the work tables. Static has never been a problem even though there is a lot of plastic of various types in many components of our production and use.

  5. Is sensitivity inversely proportional to the moisture level in the mixture? Could the cold cardboard sealed in plastic have created a humid environment, where the zip-loc bag wouldn’t have? What is the velocity difference between “far more than entertainingly close” and the range you were shooting from before?

  6. I’ve been putting off saying this, but there’s nothing for it. It’s time to face up to it. Obviously you’ll have to sacrifice a virgin.

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