Spinning my wheels…and shot my chrony too!

[Mole2017]

Well, it isn’t like I backed my car over my favorite air rifle, but yesterday was one of those days that went south, culminating with a hole in my chronograph! Enjoy the story and don't do as I did...



So, like a week ago, I had posted a confession that I had finally cleaned my BSA R10 barrel for the first time in three years. Yes, it was gross and the initial data looked like I had picked up a 2% boost in muzzle velocity. Wanting to see if that trend still held, I shot another group yesterday.

Yes, that group showed the improvement still held! So far, so good, but the last few shots also showed I was just then going off my regulator set-point. I shot some more to confirm that. “Cool!” I thought, “I have never seen that in my own rifle, so I should plot that.” By then I had an almost continuous record of the last 40 or so shots off a fill from about three outings (that first one has some older shots added to it to show the trend better), so here’s the plot:



“Wait a minute…I know that shape!” Oh great, not only have I confessed to not thinking to clean my barrel as step one of whipping a rifle into shape, I got totally misled by data that now showed I also haven’t been paying attention to my rifle enough to realize it is off its tune! I suppose it was quite a piece of luck that my before and after work fell on the "hump" of the curve from my now-out-of-tune PCP. Compare this with the plot Bob has in his discussion of tuning a regulated PCP.

Just to make sure, I refill the rifle and strap on the CB-625 for a few more measurements. If these come in at 905 FPS or so, of which I was now 95% certain they would, then I’m back to square one, though at least with a clean barrel now.

First shot, 906. Second shot, 911. Yep, looking like it. Third shot…the magazine fumbles and I fuss with the gun a moment to make sure I don’t jam the pellet. I thought I was careful not to bump the chrony still strapped to the muzzle. Now loaded again, I take the shot and something goes “whack” really close to me and something else makes a tinkling sound bouncing off some sheet metal at my feet. “whaaat was that…?” I look at the chrony to see what it measured.

I forget if I saw the hole, the misalignment with the barrel, or the screen of my chony showing “8888” like it does on a self-test, but what followed was a surreal moment of realizing what I had done and watching my chrony bleed out as the screen went through a few things and finally ended with a single segment of a digit that then faded away. I literally thought, “Well, looky here, I’ve joined the club!”

I collect my toys and go inside to assess the damage. Here’s what greets me upon opening the case:


Here’s the debris that fell out:



Here are two views of the edge of the circuit that took the brunt of the blow:



But close exam concludes that no components are actually broken or, more importantly, missing. The tinkling part was the clear window over the display. It was found under the picnic table on the patio. Amazingly the LCD is intact. A transistor and a microprocessor were knocked off their solder pads, and the leads and circuit traces in that corner were damaged.

I find some lead still smashed in the back of the cover and flake it off easily. I excavated most of the lead that was smashed into the edge of the circuit board. This is a fiberglass board, and I find lead very thoroughly pressed into the layers of glass mat and resin, but it isn’t like it is going to split the board open like a pita bread. This property of lead is what makes swaging pellets so successful. Want something fun to try? Find a piece of solder that is just long enough to stand out horizontally if clamped from one end. Clamp it somehow like that and wait. After a few minutes, the solder will have sagged under its own weight.

Anyway, after that, the repairs went pretty smoothly. The loose parts were easily re-soldered. The one sensor lead no longer had a hole/solder pad to call home, but I followed the trace and found a through-hole to which I added a thin wire and just did a “free form” connection. Here’s what that looked like:



I did have to adjust that repair to get the cover to go on correctly, but the worst was over. Actually, this is pretty routine work for me. I’ve done harder, i.e. smaller, solder jobs under a microscope. For example, I built a bank of four 0402 size LEDs and 36 gauge wire to go around a 1 mm diameter wire that went inside a tube of just 3 mm inside diameter. Before that there was an IR detector to go inside a 14 gauge hypodermic needle. Actually, it is kind of fun, but having a microscope to see what you are doing sure makes a difference!

Except for a bit where it was stuck in European metric mode until I found the manual, I was able to shoot some pellets and confirm (a) it still works and (b) my rifle still needs an adjustment. A very close call.

I might have guessed the rifle was off its tune when those early “before cleaning” shots were taken: this rifle was shooting and average 915 FPS after I last tuned it, so something must have slipped some.

But there was one other piece of good fortune yesterday: driving by a housing development near my house, I spotted a grill and a propane tank that someone has set out by the dumpster! Better still, this tank is nearly brand new and almost full! I don’t need the grill—which has certainly been used some—but the tank goes in the back seat. At home, I can’t get it to open up--like some gorilla got on this valve. I wrench it some and it moves, but I think twice of it and go inside to research the problem.

Yes, propane valves can do weird things, but I end up starting with the obvious: maybe it is already open and just the OPD is stopping the gas from flowing. I try the handle the other way; it works! Closed now, I lift the tank and tap it on ground a few times to reset the OPD. Hooking it up, I get gas to the burners of my fire pit! Apparently, the former owner had managed to disconnect it from the grill while open, tripping the OPD (and getting a faceful of propane). Now essentially disabled, they set the tank and grill by the dumpster for scavengers. A nice score! Now if I could come across a nice .22 PCP that way...

[Norcal]

[moorepower]

Your not the first to shoot a chrony . I will bet you won't be the last.

[KnifeMaker]

It has been said, There are two types of Chrony owners. Those who have shot one, and those that will.LOL


It took years, but I finally joined the club!


Knife

[Lt. Dan]

I'm a member of the club. I just cracked the black plastic around the rear photo sensor.
I laughed when I was first told to be careful and not shoot the chrony.  I laughed for years,  I don't laugh anymore. 

[Mole2017]

Thanks guys. Believe me, I already knew about this "club" and take special care of my other conventional chronograph. It sits behind a 5" by 5" square of 1/2" unknown plastic that is so tough that 19 ft-lb point blank slugs essentially leave what looks like pencil marks--just real lead now. I actually hit it a few weeks ago and almost couldn't find the mark...did its job, of course!

I was also aware of the risk to this design; I should have taken a moment to double check, regardless of whether I thought I bumped it or not.

As for the R10. I'll have to take some time to check that hammer spring setting, but the forecast is for a chance of rain for quite a while yet. Fortunately, it isn't hard to do if you have the tools ready.

PS: don't test your chrony armor at point blank ranges without hearing protection. The sound of impact will hurt your ears!

[Chris USA]

I have shot mine 1x. The 3/16" aluminum guard that goes up the front, under and up the rear saved it. Actually, it hit the rear guard and dinged it. The chrony never got hit. Was stupid and was doing an off hand chrony shot standing right by it and did align the muzzle properly. Shooting Chrony with remote screen.

Yes,... well worth taking the time to come up something,... anything.

Sticking a dowel, or something in or on the barrel can help insure correct alignment. Critical for an accurate reading.

[Habanero69er]

Welcome to the "I shot my chrony" club David.   

[Madd Hatter]

It took 6 shots but I finally killed my first chrony. It was one of thous Chinese shoot thru chronys. I've already shot my Caldwell crony but it was just a glancing hit to the top near the back.

[Lt. Dan]

I'm a member of the club. I just cracked the black plastic around the rear photo sensor.
I laughed when I was first told to be careful and not shoot the chrony.  I laughed for years,  I don't laugh anymore.

Mine still works and the crack was tiny. I have the Chrony Beta Master so my display is away from the path of the pellet. I have made arrangements so it won't happen again. Hopefully.

[Springrrrr]

I'm in but was able to repair it.

[avator]

Knocking on wood here.

[Madd Hatter]

So, do we shoot our chronys when we hear about chronyism?

[kbstingwing]

I keep hitting the light kit on mine, fortunately it still works.

[Habanero69er]

I've got one word for chrony owners. Lexan or polycarbonate.
I know, technically that's two words, but they're the same thing. Either way, it's good stuff for protecting your chrony. Just not the type that straps onto your muzzle.

[Duckfish]

Little duck tape might fix it up!

[Lt. Dan]

I've got one word for chrony owners. Lexan or polycarbonate.
I know, technically that's two words, but they're the same thing. Either way, it's good stuff for protecting your chrony. Just not the type that straps onto your muzzle.

I made a plywood tray that just fits the Chrony, at business end I have attached a 2x6 to protect the Chrony. I can do that because my display is separate.

[Habanero69er]

I have an Alpha Shooting Chrony. It too has a remote display.
I have a few 3/8" polycarbonate shields on mine. Two on the front, one on the back. The two on the front are held in place by neodymium rare-earth magnets with four rubber placers between the two pieces of polycarbonate that work as shock absorbers, as well as four rubber spacers between the chrony front face & the polycarbonate.
The piece of polycarbonate on the backside of the chrony is just there for extra protection. It too has rubber spacers & is also held in place by neodymium rare-earth magnets.