The chrono protection program

aka Stop Box V2

Same goal as before: Protect the chrono from up-to hot 10mm loads; Small / portable; Couldn't be reactive; and. protect the infrared light kit.

The 'box' was simple, as I already had a proven design. This version would be indentical in build except the depth was lessened by one 'brick' - smaller and lighter.
The light kit barrier - low mass, yet (theoretically) having enough to absorb 800ft lbs of energy. Steel bearing plates bonded together, and to 13-ply Baltic Birch.

I purposely loaded the barrier 'forward', thinking energy would be absorbed before hiting the limit of reward travel, breaking the dowels. Of course, reward momentum may flip the box. I'll test it on the next outting, it might need to be secured to the bench.

Why all of this? Time really.

My 1st chrono was, after consistent errors, 'helped' with a deliberate mercy shot.

The 2nd...

...was entirely the result of stupidity (particular guilty pistol was fully disassembled prior to that chrono session, including the rear sight).

And the 3rd is, well, protected. Cost is certainly an issue. Chrono, Digital Link, & light kit were about $240 (Unlikely I would manage to hit all three components with a single shot, but anything's possible).

It's about the 5 hours round trip to the range, and all the prep time. If the goal of the day is results, then a fair amount of time would be wasted if misfortune happened again.

Hopefully this setup is literally bulletproof.
Update: Happy to report the light kit barrier worked as intended. Hit it with a fairly hot load, chrono was undamaged.
Protection during transportation: The Plano case is well made, and pluck foam makes fitting easy.

Light kit batteries

Since I wasn't able to find an outlet in the woods...

The light kit's power supply outputs 0.2A @ 24V. I chose to wire two 12V 4.5Ah batteries in series for 24V, and a run time of approximately 22 hours (according to an online calculator).

With batteries fully charged I did a 5 hours test, then hooked up a charger - it showed full charge.

04/02/16 update: Three chrono sessions (about 18 hours runtime) and the batteries finally 'accepted' a charge (they weren't dead). This system works exceptionally well.

Update: the light kit worked perfectly, a massive improvement over daylight. Pulled the trigger a couple hundred times, chrono might have missed 4 shots.

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