Thread: Chronographs, what's the story

Are you throwing the powder charges or weighing/trickling individually?

Using mainly adi powder Rushy which is supposed to be pretty stable.
perhaps if I had left a rd in the hot chamber to long before firing, then I could put down an individual 80 odd fps to that
however these were consistant but consistantly higher/ Lower.
Having said that, in this particular case I was using N560

As perhaps in the last of the 30 06 thread , maybe it's just my crony is just not particuarly accurate.
.

Rainy day project: improve the F1 maybe? The reliance on natural light for the Chrony and the resulting inconsistency has been quite a problem for me (and the cost of 9V batteries). You could try repackaging the guts of it to be covered on both sides and an oversized top so there is no chance of sun shining on the sensor apertures and keeps the rain off, illuminate the sensors instead with a row of LEDs above each, run it (and the LEDs) off 8x AA rechargeables. Works a treat, rain, shine, light or dark. I'll take a pic and post next time I have it out. Maintain exactly 12" between centres for the sensors as in the original, same for the LEDs, to keep the calibration.

Originally Posted by Puffin

Rainy day project: improve the F1 maybe? The reliance on natural light for the Chrony and the resulting inconsistency has been quite a problem for me (and the cost of 9V batteries). You could try repackaging the guts of it to be covered on both sides and an oversized top so there is no chance of sun shining on the sensor apertures and keeps the rain off, illuminate the sensors instead with a row of LEDs above each, run it (and the LEDs) off 8x AA rechargeables. Works a treat, rain, shine, light or dark. I'll take a pic and post next time I have it out. Maintain exactly 12" between centres for the sensors as in the original, same for the LEDs, to keep the calibration.

Yes please, post up a pic when you can. I need to do something like this to my F1 as it does my head in too.

kj

Same please.

Originally Posted by Kscott

Same please.

++1

I've been thinking about building a plywood box to encase mine in ...


Tim

How much light do you need to provide via the LED's? Can you have too much?

As can be seen the conversion was mainly a mechanical one. Electrically the Chrony circuit has an on-board 5V regulator so either 6 or 8 cells should be fine. Operating time between charges is set by the current run through the LEDs as the chrony circuit itself doesn't draw much.

On the question of brightness I'm currently running 10mA through each LED and I have 20 in a row to get that light-bar effect, all in parallel, so 200mA through the LEDs - the front & back strips are then run in series. 8-10 hour run time. The LEDs came from Jaycar Electronics as some sort of pre-made strip lighting that can be cut to length off a reel. I had 2-3 metres of it and that gave me 60-80 LEDs. The tricky bit is that these then need to be removed and rearranged side-by-side on your own bit of circuit board with their own series resistor each to make a pair of 55mm wide solid strips. They are Surface mount style so this will test your soldering skills. Once done it does work really well and doesn't miss a beat. Less forgiving than the plastic screen if it took a hit though.

Looks good, thanks for the ideas

Close up of the small strip of printed circuit board with the LEDs on it.



Wildman that may be right, it may be possible to have too much light. I vaguely recall that cranking the LEDs up took the sensor circuitry out of it's designed operating range - a bit like trying to get them to work with direct sunlight. The LEDs on this one have a voltage regulator between them and the batteries so the light intensity can be adjusted. Feel free to PM if you like for other details.

Cheers, ta.

hi all
yeah, I know its an old thread but with recent experience and not seeing mention of my take on it....
l've found I need to take care on aligning the chrony parallel with the shot, one end higher than the other shortens the bullet path, hence higher (different) numbers.

Originally Posted by gimp

Shooting F1

it's been shot, hit with fragments from an exploding suppressor, and still works

it just needs bright light to be accurate

My 338 Lapua blast blew the front off my F1 and rolled it around a tad I managed to fit it back together still working but I use a Magnetospeed now seems simpler but it has affected my grouping and point of impact.

Originally Posted by xtightg

My 338 Lapua blast blew the front off my F1 and rolled it around a tad I managed to fit it back together still working but I use a Magnetospeed now seems simpler but it has affected my grouping and point of impact.

I modified mine with a 480gr round ball at 1200fps. Rolled the bugger in the dirt too... On comparison to all my previous loads, it's still spot on and I still use it.

still works?