Distance from Cronograph

STEVE M · August 14, 2000, 08:33 AM

Just curious, at what distance does everyone cronograph their rounds? I've always been at 8ft from the muzzle (rifle and pistol). What about everyone else, closer or farther away, same or different for rifle/pistol?

------------------
keep your options open &
never miss!

Bottom Gun · August 14, 2000, 12:07 PM

The instructions for mine say 10 ft minimum. but last time out I was set up at 12 ft because of the terrain and got nothing but error messages. I assumed because the muzzle blast was still too severe at that distance.
The muzzle blast from my first shot took one of the skyscreens off the machine.
Next time out, I'll try it at 20 or 25 ft and see if that helps. If not, maybe I'll have to make a blast shield for it.
Of course my problem might be operator error since I'm relatively new to chronographs.

Paul B. · August 14, 2000, 12:20 PM

I believe the standard distance for a chronograph is 15 feet. This is what I have always used when clocking loads. I have noticed that sometimes I will get error messages depending on the time of day. At the range I go to, morning shoots usually come out fine, but in the afternoon, readings can get squirrely or just plain error messages. I think it has to do with the angle of the sun, and even skyscreens fail to stop it completely. One of these days, I'm going to make my own design of skyscreen that covers a larger area. Maybe that'l cure the problem.
Paul B.

Bottom Gun · August 14, 2000, 12:23 PM

Paul B,

Are there times when it might be more advantageous to leave the skyscreens off altogether?

Monkeyleg · August 14, 2000, 03:17 PM

Bottom gun, the skyscreens are for sunny days. A clear sky doesn't transmit as much light to the sensors as a cloudy sky does. The skyscreens are there to be illuminated by the direct sun.

I keep mine out about 15 feet or so. Any closer and I get error readings from the muzzle blast.

Dick
Want to send a message to Bush? Sign the petition at http://www.petitiononline.com/monk/petition.html and forward the link to every gun owner you know.

Bottom Gun · August 14, 2000, 04:07 PM

Ah-Ha! I knew this would be educational.

Will it help to tilt the unit so the skyscreens are directly facing the sun?

johnwill · August 14, 2000, 07:13 PM

No, the photo sensors are oriented so they have a field of view of the screens. Leave them the way the factory intended for best operation.

STEVE M · August 15, 2000, 06:17 AM

Do you measure from the first skyscreen or to the middle of the set-up?

Paul B. · August 15, 2000, 04:01 PM

Bottom gun. I leave the skyscreens off on cloudy days. Even with high thin cloudiness, the chrongraph should work well without screens. The screens are used on bright sunny days to reduce the "glint" from the bullet. I guess it confuses the "eyes" that use the shadow of the bullet or something.

Steve M. If you want the neasurement to be a reading at 15 feet, place the chronograph so that the center, between the two "eyes" is at 15 feet. If it is not that important, place the start screen 15 feet out and let it go at that. I doubt that the velocity will change that much, and some rifles have sufficient muzzle blast that a screen closer than 15 feet will have more error messages than not.
Paul B.

Bottom Gun · August 15, 2000, 07:47 PM

Paul B,
Thanks for clearing that up for me. That's very helpful and I appreciate it. I've been shooting and reloading for a number of years, but have never had a chronograph until now.

How about another question? Is the height of the bullet path above the "Eyes" critical? I belive my instructions call for the bullet to travel 4 to 8 inches above the unit. Will there be any difference in accuracy if I send one through at 6" above and another at 8" above the unit?
I guess what I'm trying to ask is: Will a tight group through the "eyes" result in a more accurate measurement and does the height of the group matter so long as it's within the specified range?

Thanks in advance,

Ken

Clark · August 15, 2000, 09:54 PM

One must be far enough away to not get the gasses affecting the measurement.

One must also be close enough so the chrono is not hit by stray bullets.

In my case there often is no such distance

Paul B. · August 16, 2000, 02:03 PM

Bottom Gun. I don't think the height of the bullet matters much as long as it falls within the parameters of the chronograph. If there was a difference, it would not be sufficient to alter the average velocity anyway. We're probably talking plus or minus 5 to 10 FPS, maybe even less. I've never given it much thought, to be perfectly frank with you. Frankly, I try to keep the bullets going on the higher side of the limits. So if 4 to 8 inches are the parameters, I try to keep them at 8 inches, or close to it.
I've murdered two chronographs already. Well one anyway. The Chrony can be repaired. A .44 Mag put the quietus to my Oehler and a .44 Spl seriously wounded my Shooting Chrony. I don't care how careful you are, it can always happen. The Oehler probably had well over 5,000 rounds of test ammo of all sorts over it, and the chrony just about the same. I guess, for me anyway, a new chronograph every 5 or 6 years is about par for the course. Mine did get used a lot, sometimes two or three times a week.
Stuff happens, no matter how careful you are.
Paul B.

Bottom Gun · August 16, 2000, 03:02 PM

Paul B,

Shooting Chrony put a little note in with my unit which said that if you do shoot it up, return it to them for repair.
Seems like I read a letter or two in the gun rags where shooters say they sent them back and they were repaired free.
Might pay you to drop them a line.

Southla1 · August 16, 2000, 04:15 PM

I never managed to hit a chrony but I certainly comitted murder of one fine (Well it used to be fine) Focal tripod! The chrony survived just fine........there was not enough of the tripod left to bury!

I did have to look around for some of the lil steel rods that hold the skyscreen but they were OK. .44 Magnum wins again!

------------------
Carlyle Hebert

[This message has been edited by Southla1 (edited August 16, 2000).]

WalterGAII · August 16, 2000, 09:09 PM

If you'll replace the steel rods with wooden dowels, you won't cause any damage to the skyscreens or chrony if you happen to hit one or more of the rods.

I found that my Chrony will give false high readings when I don't use the skyscreens on a pretty bright day. I also don't place my chrony as far away as some of you guys. For handgun stuff I set the chrony up four or five feet from the muzzle.

I don't shoot big-bore rifles, but don't have any trouble with .223's or .243's at seven to ten feet.

JimWolford · August 16, 2000, 09:57 PM

I use a Pact model chrono and put the screens out at the end of the wires <s> which would be about 15 feet I guess.

Couple weeks ago I was testing a 22 Jet revolver and was getting some totally unbelieveable variations- bad enough that I quit for the day.

After getting back to the house, I called the company and discribed my problems, the person on the other end said "I bet it was a beautiful bright sunshiny day, right?" It seems their equipment cant handle too much sunshine.

The suggested cure? turn the screens on their side( facing *away* from the sun ) and shoot "past" it, not "over" it.

Works just fine<G>

Jim

------------------
Lay up some blackpowder and flints
The rest we can build, if need be

August 14, 2000, 08:33 AM	#1
STEVE M Senior Member Join Date: February 7, 1999 Location: TN. USA Posts: 607	Just curious, at what distance does everyone cronograph their rounds? I've always been at 8ft from the muzzle (rifle and pistol). What about everyone else, closer or farther away, same or different for rifle/pistol? ------------------ keep your options open & never miss!

August 14, 2000, 12:07 PM	#2
Bottom Gun Senior Member Join Date: October 13, 1998 Location: Arizona Territory Posts: 1,092	The instructions for mine say 10 ft minimum. but last time out I was set up at 12 ft because of the terrain and got nothing but error messages. I assumed because the muzzle blast was still too severe at that distance. The muzzle blast from my first shot took one of the skyscreens off the machine. Next time out, I'll try it at 20 or 25 ft and see if that helps. If not, maybe I'll have to make a blast shield for it. Of course my problem might be operator error since I'm relatively new to chronographs.

August 14, 2000, 12:20 PM	#3
Paul B. Senior Member Join Date: March 28, 1999 Location: Tucson, AZ Posts: 3,802	I believe the standard distance for a chronograph is 15 feet. This is what I have always used when clocking loads. I have noticed that sometimes I will get error messages depending on the time of day. At the range I go to, morning shoots usually come out fine, but in the afternoon, readings can get squirrely or just plain error messages. I think it has to do with the angle of the sun, and even skyscreens fail to stop it completely. One of these days, I'm going to make my own design of skyscreen that covers a larger area. Maybe that'l cure the problem. Paul B.

August 14, 2000, 12:23 PM	#4
Bottom Gun Senior Member Join Date: October 13, 1998 Location: Arizona Territory Posts: 1,092	Paul B, Are there times when it might be more advantageous to leave the skyscreens off altogether?

August 14, 2000, 03:17 PM	#5
Monkeyleg Senior Member Join Date: January 25, 2000 Posts: 4,625	Bottom gun, the skyscreens are for sunny days. A clear sky doesn't transmit as much light to the sensors as a cloudy sky does. The skyscreens are there to be illuminated by the direct sun. I keep mine out about 15 feet or so. Any closer and I get error readings from the muzzle blast. Dick Want to send a message to Bush? Sign the petition at http://www.petitiononline.com/monk/petition.html and forward the link to every gun owner you know.

August 14, 2000, 04:07 PM	#6
Bottom Gun Senior Member Join Date: October 13, 1998 Location: Arizona Territory Posts: 1,092	Ah-Ha! I knew this would be educational. Will it help to tilt the unit so the skyscreens are directly facing the sun?

August 14, 2000, 07:13 PM	#7
johnwill Senior Member Join Date: April 6, 2000 Location: PA Posts: 3,451	No, the photo sensors are oriented so they have a field of view of the screens. Leave them the way the factory intended for best operation.

August 15, 2000, 06:17 AM	#8
STEVE M Senior Member Join Date: February 7, 1999 Location: TN. USA Posts: 607	Do you measure from the first skyscreen or to the middle of the set-up?

August 15, 2000, 04:01 PM	#9
Paul B. Senior Member Join Date: March 28, 1999 Location: Tucson, AZ Posts: 3,802	Bottom gun. I leave the skyscreens off on cloudy days. Even with high thin cloudiness, the chrongraph should work well without screens. The screens are used on bright sunny days to reduce the "glint" from the bullet. I guess it confuses the "eyes" that use the shadow of the bullet or something. Steve M. If you want the neasurement to be a reading at 15 feet, place the chronograph so that the center, between the two "eyes" is at 15 feet. If it is not that important, place the start screen 15 feet out and let it go at that. I doubt that the velocity will change that much, and some rifles have sufficient muzzle blast that a screen closer than 15 feet will have more error messages than not. Paul B.

August 15, 2000, 07:47 PM	#10
Bottom Gun Senior Member Join Date: October 13, 1998 Location: Arizona Territory Posts: 1,092	Paul B, Thanks for clearing that up for me. That's very helpful and I appreciate it. I've been shooting and reloading for a number of years, but have never had a chronograph until now. How about another question? Is the height of the bullet path above the "Eyes" critical? I belive my instructions call for the bullet to travel 4 to 8 inches above the unit. Will there be any difference in accuracy if I send one through at 6" above and another at 8" above the unit? I guess what I'm trying to ask is: Will a tight group through the "eyes" result in a more accurate measurement and does the height of the group matter so long as it's within the specified range? Thanks in advance, Ken

August 15, 2000, 09:54 PM	#11
Clark Senior Member Join Date: December 4, 1999 Location: WA, the ever blue state Posts: 4,678	One must be far enough away to not get the gasses affecting the measurement. One must also be close enough so the chrono is not hit by stray bullets. In my case there often is no such distance

August 16, 2000, 02:03 PM	#12
Paul B. Senior Member Join Date: March 28, 1999 Location: Tucson, AZ Posts: 3,802	Bottom Gun. I don't think the height of the bullet matters much as long as it falls within the parameters of the chronograph. If there was a difference, it would not be sufficient to alter the average velocity anyway. We're probably talking plus or minus 5 to 10 FPS, maybe even less. I've never given it much thought, to be perfectly frank with you. Frankly, I try to keep the bullets going on the higher side of the limits. So if 4 to 8 inches are the parameters, I try to keep them at 8 inches, or close to it. I've murdered two chronographs already. Well one anyway. The Chrony can be repaired. A .44 Mag put the quietus to my Oehler and a .44 Spl seriously wounded my Shooting Chrony. I don't care how careful you are, it can always happen. The Oehler probably had well over 5,000 rounds of test ammo of all sorts over it, and the chrony just about the same. I guess, for me anyway, a new chronograph every 5 or 6 years is about par for the course. Mine did get used a lot, sometimes two or three times a week. Stuff happens, no matter how careful you are. Paul B.

August 16, 2000, 03:02 PM	#13
Bottom Gun Senior Member Join Date: October 13, 1998 Location: Arizona Territory Posts: 1,092	Paul B, Shooting Chrony put a little note in with my unit which said that if you do shoot it up, return it to them for repair. Seems like I read a letter or two in the gun rags where shooters say they sent them back and they were repaired free. Might pay you to drop them a line.

August 16, 2000, 04:15 PM	#14
Southla1 Member In Memoriam Join Date: March 19, 2000 Location: Jeanerette, La. Near the Posts: 1,999	I never managed to hit a chrony but I certainly comitted murder of one fine (Well it used to be fine) Focal tripod! The chrony survived just fine........there was not enough of the tripod left to bury! I did have to look around for some of the lil steel rods that hold the skyscreen but they were OK. .44 Magnum wins again! ------------------ Carlyle Hebert [This message has been edited by Southla1 (edited August 16, 2000).]

August 16, 2000, 09:09 PM	#15
WalterGAII Junior member Join Date: November 7, 1999 Posts: 1,516	If you'll replace the steel rods with wooden dowels, you won't cause any damage to the skyscreens or chrony if you happen to hit one or more of the rods. I found that my Chrony will give false high readings when I don't use the skyscreens on a pretty bright day. I also don't place my chrony as far away as some of you guys. For handgun stuff I set the chrony up four or five feet from the muzzle. I don't shoot big-bore rifles, but don't have any trouble with .223's or .243's at seven to ten feet.

August 16, 2000, 09:57 PM	#16
JimWolford Member Join Date: June 20, 2000 Posts: 63	I use a Pact model chrono and put the screens out at the end of the wires <s> which would be about 15 feet I guess. Couple weeks ago I was testing a 22 Jet revolver and was getting some totally unbelieveable variations- bad enough that I quit for the day. After getting back to the house, I called the company and discribed my problems, the person on the other end said "I bet it was a beautiful bright sunshiny day, right?" It seems their equipment cant handle too much sunshine. The suggested cure? turn the screens on their side( facing away from the sun ) and shoot "past" it, not "over" it. Works just fine<G> Jim ------------------ Lay up some blackpowder and flints The rest we can build, if need be