Well.. after two weeks I found some time to fix my shot Chrony.
It wasn't damaged as bad as I think.

I will gradually make modification to shot proof it later.

Should have upload the pictures in reverse order.

I am lucky that the damage is quite superficial.

If you see the picture 2 and 3, you can see the piece of jacket material lodged onto the damaged chip. It sort of just clipped the LCD panel and give it a crack that just out of the important area

So there..

I will post more later on as I modify the thing.

Good thing it was a pretty common 7400 logic chip that it damaged huh Gelan ??

Dimitri

Hit it with a BB gun? Where's the hole?

O.K., Why'd you shoot it in the first place? Was it acting strangely? Foaming at the sensor? Did it attack? Oh, the Humanity!

I found the hole! Next time, use enough gun!

But it didn't even penetrate the IC chip...

Bushmaster,

A peice of the jacket of what ever he was shooting hit the Chrony. Not the entire bullet.

Dimitri

In that case he needs a better bullet...

LoL

I was trying this swaged 130gn hollowpoint from a Sydney maker called The Bullet Factory.


If I am not wrong, RPM = (720 x Velocity)/ twist rate in inches

This bullet is designed to be used in a .308 cartridge shooting at about 3000fps in 1:12 twist rate which gives about 180,000rpm.

I am sending it out at 2200 fps in 1:8 twist and it gives about 198,000rpm.

The differences is 18000 rpm or about 10%, which should be tolerable.
But for that one bullet, the jacket may be nicked or unbalanced etc , and I am the "beneficiary" of it...

Anyhow, I am glad that the chrony works now and I am designing it to be bullet proof in the near future.

So when are you going to start making your own chronographs? Are you going to run 20' leads to the sensors or put them in with the electronics so they can be shot up like the Chrony's?

Hi Paul,

I am thinking of using RF 433 MHz connection wireless, I hate leads.. they are really cumbersome. them RF modules are small, cheap and don't use much power.

I will still be using the chrony's sensor because there are a couple of optical lenses in the sensor that I could not reproduce.

And I think I will put in a 10mm high tensile steel plate right in front of the unit so to afford it a tad more bulletproof. It will just increase the weigh a little bit.

gelandangan,
That all sounds ok but you better make that front plate at least 13 mm. My 357 has gone straight through a 3/8" piece of T1 steel. The 8" gong didn't even swing - I thought I had missed it. Nice clean hole light a paper punch.
Just a real fast 140 grain JSP speer. 1/2" T1 dents but there aren't any holes.

Angle the plate. I've thought about adding protection to mine too but I was just going to put an angled piece of lexan in front of it. It wouldn't protect against a dead on hit with a bullet but most of the time all we need to do is deflect some debris, be it powder, piece of jacket or sabot, etc. And unless you have one heck of a tripod the lexan is a lot lighter.

I have a better idea...Don't hit your chronograph...