FYI, I just shot my chrony..

I did not actually shot it, its the bullet somehow broke up and a piece of copper jacket material shot off and hits the chrony right next to the LCD display. I reckon its because I tried to push the pellet too fast in my FAST rifling (1 in 8 ) 300 Whisper and the bullet just broke apart due to the resulted high RPM .

If any of you have a CIRCUIT DIAGRAM for the damned thing, I would be most grateful to get a copy.

On the brighter side, I managed to get a 130grains bullet to 2300 fps with only 16.5 grains of AR2205. I know its nothing compares to a standart caliber, but if you consider that a 30-30 needs at least 24 grains of powder to push 130gn bullet to the same speed, the Whisper is very economical indeed!!

Don't feel too bad; I'm currently on my third Chrony...the others died violent deaths because I messed up.

Chrony #1 died a valiant death when a .223 I was testing for someone else sent a bullet through the casing. I had neglected to note that the front scope mounts had worked loose causing the scope/bore angle to be excessive and the bullet to exit far lower than expected. Chrony #2 proved to be no match for a 45/70 load that crashed through it when a makeshift shooting bench collapsed at the exact second I triggered the round. Again, my fault.

A few tips might help others:

When using the Chrony it is best to use a firm support such as a camera tripod. Carefully adjust height and angle until you have a clean shot through the sunshade braces with a reliable backstop behind it.

Take care to ensure that the Chrony is completely unfolded. The distance between the two sensors is critical for accuracy. A partially folded unit will reduce this distance and create erroneous readings. Those 3,800 fps readings with your .223 and 55-grain bullets are unreasonable; check to see if the Chrony is unfolded all the way.

Place a strip of clear packing tape over the front and rear sensors. This helps keep dust out of the sensor openings and seems to help with accurate readings too. This may be a result of “softening” sunlight and allowing a clearer bullet shadow to reach the sensors.

Place a wide strip of black tape between the front sunscreen braces 6" above the unit body. Never allow your cross hairs or open sights to drop below this line when shooting. Remember that most scopes average 1 1/2" higher than the actual bullet path from the muzzle and open sights run between .7 - .9" depending on type. The bullet will be traveling lower than your sights!

Make sure that you are using a firm, sturdy shooting bench (see Chrony #2, above!) and shooting bags.

I never allow anyone else to shoot through my Chrony. If someone wants to check loads, I do the shooting. Of course, with my previous track record that doesn't necessarily mean that it is safe.

Safe shooting and good luck with your quest.

gelandangan & Singleshooter,
Do not feel bad, there are only those that have and those that are going to.

My favorite rangemaster chrony story is the shooter that came out to the range with the brand new PAC and his new 445SM DW gun. First shot he centered the PAC, blew the guts right out the back. Feeling dumb, he just packed up went home and ordered another PAC, without a word to anyone. The new PAC arrived, back to the range he comes, with his buddies, would not listen to tall sights, be careful, etc., .... yep, first shot,,,, boom, chunks fell from the sky.

I know it was mean, but I laugthed till I cried, I had to go sit down.

The steel support for my light defuser has a bullet cut about 1/2 of its width. Wind gust, bullet blew up and cut the wires off the back sensor. The sensor was peppered with fragments.
Ed

Shot your chronogragh did you??????????????

Welcome to the NO I DID NOT JUST DO THAT CLUB !!!!!!!!!!!!!!!!!!!!!!!

Just a little note to those thinking about buying a chrono or in gelandangan's position the need to replace.......................

Consider the Pact model one. When you shoot one of these you only need to replace the sensors and skysceens. (And maybe your tripod).
The eloctronics are a seprate box.

I don't know what they cost now, but when I shot my sensors, it cost me less than $20.00 with shipping.

swampfox.................. wind gust????????????????????????

8-OI bought one of the higher dollar gamma master units,afterspending the money I decided I would do the reading of the instructions first and NOT"john wayne" it for once.I replaced the aluminum rods for the sunshade with wooden dowel rod of the same diameter,covered the screens with the clear tape,taped with colored tape rings- all four wooden rods to be able to see the correct leveling of the unit and to tell the correct height of the crosshairs.After all of that I still was'nt satisfied that I might not kill the chrony-so I built a sheet metal base that attached to the bipod for the chrony to sit on,and made the sheet metal base about 4 inches longer than the front of the unit,upon which I put a 5X6inch piece of 3/4 inch steel plate on about a 45 degree angle from top to bottom if front of the forward sensor.This way itSHOULDdeflect any stupid shot I might make over the top of the unit and just make me feel stupid,instead of stupid with a broken chrony!
BTW-if you hit one of the aluminum rods with a bullet-you might just be sending the unit back to chrony for a new sensor!

Geland - sorry to hear about the chrony! I am so cheap I think I would take it pretty hard and might even call my voicemail and threaten myself.

I realize this wasn't the case so I hope this assists somebody out there, but when I line mine up I use a cheap little laser keychain that I tape or otherwise temporarily fasten to the barrel and I hold a white piece of paper at the far end of the chrony to get me there once I have securely fixed my rifle and sight on my target, I adjust my chrony to coincide from there.

Wiley, good idea.

Chambered, Yep it was a wind gust that blew the sensor bar sideways at the front, just a I pulled the trigger. With a scope you can not see an angled obstruction below the line of sight. Unit is one of those PAC jobs with the two pararell steel bars and sensors screwed to them, covered by two opaque defusers supported by four flat steel arms that stick up at about 45 degrees. It is big and ugly at the range and tends to twist on the tripod mounting bolt in a high wind. The guts are on the bench with me, so safe, somewhat.....
Ed

PS; I just replaced the stop sensor with its wire and went on. Now I tighten the tripod mounting bolt with a big screw driver. Every time I open the box I get to re-live the feeling of stupidity.....there is the support, bullet cut and all,,,

chambered221 wrote:

Shot your chronogragh did you?????????????? Welcome to the NO I DID NOT JUST DO THAT CLUB !!!!!!!!!!!!!!!!!!!!!!! Just a little note to those thinking about buying a chrono or in gelandangan's position the need to replace....................... Consider the Pact model one. When you shoot one of these you only need to replace the sensors and skysceens. (And maybe your tripod). The eloctronics are a seprate box. I don't know what they cost now, but when I shot my sensors, it cost me less than $20.00 with shipping.

I should have bought the MASTER model where the electronics were separated from the sensors.

Well, I am an electronics engineer, the chrony's electronics would not trouble me much.
Its the optic elements in the sensor body that I could not make.

So, if there is no circuit diagram, I amy have to design one myself.. and make a better one at that

Swampfox

My apologies I thought you were using one of those excusses I've been known to throw in

Kinda like the oak tree that saved the deer I was shooting at one time!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Honestly!!!!!!!!!!! that tree jumped over a good 3 feet to save that deer!!!!!!!!!!!!!!!!!

Gelan: IIRC, the Chrony folks will rebuild a shot up Chrony for a reasonable amount. Wouldn't hurt to ask them. Some places sell refurbished models. Good luck.

gelandangan wrote:

Well, I am an electronics engineer, the chrony's electronics would not trouble me much. Its the optic elements in the sensor body that I could not make. So, if there is no circuit diagram, I amy have to design one myself.. and make a better one at that

If you can make them better and cheaper than the Chony's you have a big market! I may be in the market for my third Chronograpg - I've never owned a Chrony but I may look into one of the others.

That sucks dont it? Its like watching money just float away, And there aint nothing you can do but go spend more.

I had a friend once who mounted his dead chrony on a wall mount and it still decorates his reloading room.