Build yr own CHRONOGRAPH ???

Dead-Nuts-Zero · September 17, 2005, 12:15 AM

I found this on ebay. Has anyone seen this one before? Take a look...

http://cgi.ebay.com/HOW-FAST-IS-YOUR...QQcmdZViewItem

cracked butt · September 17, 2005, 02:07 AM

Looks like something that you would have to put on a trailer to bring to the range. Probably a close to expensive to build as to buy one of the cheap Chronys from midway when they have a sale.

T. O'Heir · September 17, 2005, 02:07 AM

Stay away from E-bay. They're anti-firearm.
"...This vintage plan..." Should tell you it's BS.

mtnboomer · September 17, 2005, 02:36 AM

Probably a copy of plans from the 1920's! While it says "simple to use", it won't be as it will require a ton of mathmatical equations to get your velocities.

Yea, just buy a Chrony!

Dead-Nuts-Zero · September 17, 2005, 08:38 PM

Ohhh, I had no intentions of buying it. I just thought it was kinda unique and wanted to share it with ya all.

mtnboomer · September 17, 2005, 09:16 PM

Yeah, probably for someone who collects odd shooting-related stuff it would be a great thing.

Crosshair · September 17, 2005, 10:04 PM

*Looks at $90 Chronograph* $90 is expencive? I've had ammo orders that where more than that.

armedandsafe · September 17, 2005, 11:18 PM

I used to design and build chronographs back in the early 60s. The hardest part was the screens, but that was just fussy-work. Of course, I was measuring the velocity of rather larger projectiles (can you say Red-Eye, boys 'n girls?) When we got reliable light sensors, it became much simpler.

The tunnel version pictured there is not very good for practically measuring velocity, as it is too sensitive to muzzle flash and powder/gas exhaust. Cute ad, though.

Pops

Jim Watson · September 18, 2005, 08:12 AM

Pops, I don't think this is a "tunnel" chronograph to be affected by muzzle blast, I think it is a rotary drum design. Look at where the gun is in the picture. No electricals except the drive motor. Velocity determined by how far the drum rotates as the bullet crosses its diameter.

Dave Haven · September 19, 2005, 11:30 PM

That's how it was done before electronics.

**Unclenick** · October 6, 2005, 09:52 PM

Actually, the really old way is with a ballistic pendulum. I built one and mesured the speed of an airgun pellet with it for my first year physics project in college. This gadget's wouldn't require all the calculations a ballistic pendulum does, but you would need to know its rotational velocity accurately. Unless you had a calibrated strobe light or drove it with a stepper motor and timting belt, I don't know how you would manage to be sure you didn't have errors due to motor and belt slip? Probably not a very sound approach.

Nick

tactikalwarfare · October 8, 2005, 01:58 AM

I thought it looked like a miss fire canister, looks like something of the sort...

ebay is a rip when it comes to plans and such, it will turn out to be somthing stupid like, "if it can shoot though a select number of boards, your shootin' around ???fps...."

LOL!!!

September 17, 2005, 12:15 AM	#1
Dead-Nuts-Zero Senior Member Join Date: August 26, 2004 Posts: 579	Build yr own CHRONOGRAPH ??? I found this on ebay. Has anyone seen this one before? Take a look... http://cgi.ebay.com/HOW-FAST-IS-YOUR...QQcmdZViewItem __________________ . . BANG------------ >>> !

September 17, 2005, 02:36 AM	#4
mtnboomer Senior Member Join Date: July 9, 2004 Location: Oklahoma by birth. America by the grace of God. Posts: 635	Probably a copy of plans from the 1920's! While it says "simple to use", it won't be as it will require a ton of mathmatical equations to get your velocities. Yea, just buy a Chrony! __________________ Quando Omni Flunkus Moritati (If all else fails - play dead!) Support the Second Amendment. Join the NRA > http://www.nra.org < Oklahoma State & Big 12 - #1 GO POKES!!!!!

September 17, 2005, 08:38 PM	#5
Dead-Nuts-Zero Senior Member Join Date: August 26, 2004 Posts: 579	Ohhh, I had no intentions of buying it. I just thought it was kinda unique and wanted to share it with ya all. __________________ . . BANG------------ >>> !

September 17, 2005, 09:16 PM	#6
mtnboomer Senior Member Join Date: July 9, 2004 Location: Oklahoma by birth. America by the grace of God. Posts: 635	Yeah, probably for someone who collects odd shooting-related stuff it would be a great thing. __________________ Quando Omni Flunkus Moritati (If all else fails - play dead!) Support the Second Amendment. Join the NRA > http://www.nra.org < Oklahoma State & Big 12 - #1 GO POKES!!!!!

September 17, 2005, 11:18 PM	#8
armedandsafe Senior Member Join Date: January 9, 2005 Location: Moses Lake WA Posts: 1,001	I used to design and build chronographs back in the early 60s. The hardest part was the screens, but that was just fussy-work. Of course, I was measuring the velocity of rather larger projectiles (can you say Red-Eye, boys 'n girls?) When we got reliable light sensors, it became much simpler. The tunnel version pictured there is not very good for practically measuring velocity, as it is too sensitive to muzzle flash and powder/gas exhaust. Cute ad, though. Pops __________________ Armed and Safe: Not just a theory If it time to bury them, it is time to dig them up. Remember, "Behind every blade of grass."

September 17, 2005, 02:07 AM	#2
cracked butt Senior Member Join Date: December 22, 2001 Location: southeastern wisconsin Posts: 537	Looks like something that you would have to put on a trailer to bring to the range. Probably a close to expensive to build as to buy one of the cheap Chronys from midway when they have a sale.

September 17, 2005, 02:07 AM	#3
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	Stay away from E-bay. They're anti-firearm. "...This vintage plan..." Should tell you it's BS.

September 17, 2005, 10:04 PM	#7
Crosshair Senior Member Join Date: December 16, 2004 Location: Grand Forks, ND Posts: 5,333	Looks at $90 Chronograph $90 is expencive? I've had ammo orders that where more than that.

September 18, 2005, 08:12 AM	#9
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,535	Pops, I don't think this is a "tunnel" chronograph to be affected by muzzle blast, I think it is a rotary drum design. Look at where the gun is in the picture. No electricals except the drive motor. Velocity determined by how far the drum rotates as the bullet crosses its diameter.

September 19, 2005, 11:30 PM	#10
Dave Haven Senior Member Join Date: February 1, 2000 Location: near Flagstaff, AZ Posts: 790	That's how it was done before electronics.

October 6, 2005, 09:52 PM	#11
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,060	Actually, the really old way is with a ballistic pendulum. I built one and mesured the speed of an airgun pellet with it for my first year physics project in college. This gadget's wouldn't require all the calculations a ballistic pendulum does, but you would need to know its rotational velocity accurately. Unless you had a calibrated strobe light or drove it with a stepper motor and timting belt, I don't know how you would manage to be sure you didn't have errors due to motor and belt slip? Probably not a very sound approach. Nick

October 8, 2005, 01:58 AM	#12
tactikalwarfare Junior Member Join Date: October 1, 2005 Location: atlantic city Posts: 9	I thought it looked like a miss fire canister, looks like something of the sort... ebay is a rip when it comes to plans and such, it will turn out to be somthing stupid like, "if it can shoot though a select number of boards, your shootin' around ???fps...." LOL!!!

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