Initial speed measuremnts by 1900?

JorgeO · 12-14-2008, 06:58 PM

In his "The Borchardt-Luger History" pages, M. Paul Regnier states that one of the parameters used by the Swiss army to choose the Luger was "Speed - measure of the initial speed, 5 shots per weapon"

http://www.luger-genesis.com/luger_h...e_specs_5.html

Today we have chronometers, but how was such a measurement done over 100yrs ago?

Thanks,

JorgeO · 12-14-2008, 08:47 PM

If the method was based in conservation of momentum, I've already found it.

If not, I still would like to know how.

Thanks!

alvin · 12-14-2008, 09:37 PM

Ballistic pendulum.... I assume.

JorgeO · 12-15-2008, 07:56 AM

Ballistic pendulum - that could be the name of what I had in mind.

http://www.wooster.edu/physics/lehma...b_6_Bullet.pdf

Steinar · 12-15-2008, 08:33 AM

Several ways to do this, but I guess the metod mention above was most likely used.

As a kid, I found out the speed of my Daisy Winchester pellet gun by shooting at a dry tree with the help of my dad clocking the time from the bang until we heard the impact.
With a distance of 83m, we knew that it would take the 1/5th of a second for the sound to reach us. And by that I found a fairly accurate estimate

JorgeO, DVD was sent today btw

John Sabato · 12-15-2008, 10:56 AM

The book that well documents the ballistic pendulum and many other ballistics-related procedures well is:

Hatcher's Notebook, by General Julian S. Hatcher... who was one of the big wheels in the U.S. military armory system in the early part of the 20th century. Julian Hatcher retired as a U.S. Army major general, ...was a technical editor for The American Rifleman, and author of Machine Guns, Pistols and Revolvers and Their Use, and Textbook of Firearms Investigation, Identification and Evidence. He was director of the National Rifle Association from 1922-1946

http://www.amazon.com/Hatchers-noteb.../dp/B0007FHLUK

JorgeO · 12-15-2008, 11:04 AM

- Morgan Kane

You can improve your method nowadays!

http://arxiv.org/pdf/physics/0601102

Thanks for the DVD!

- John Sabato

Thanks for the book and link!

unspellable · 12-19-2008, 07:12 PM

The method originally used to measure the velocity from the Luger involved the bullet severing two metal foil strips placed about 15 m or 50 ft apart. The foil carried a current. When the first strip was severed it interrupted the current to an electromagnet releasing a weight. The second strip on being severed induced a spark that marked a tape pulled by the falling weight. The method was actually quite accurate. One should bear in mind that what was actually measured was the average speed from around 5 feet to 55 feet. (The same method was used in both metric and English unit countries, 50 ft between strips in English countries pistols, 100 feet for rifles.) It's more accurate than the ballistic pendulum.

I did the ballistic pendulum thing for my project in my first college physics class. I suppose that's giving away my age. Fancy dragging a big bore revolver into the physics building these days!

12-14-2008, 06:58 PM	#1
JorgeO User Join Date: Nov 2008 Location: Brazil Posts: 28 Thanks: 1 Thanked 0 Times in 0 Posts	Initial speed measuremnts by 1900? In his "The Borchardt-Luger History" pages, M. Paul Regnier states that one of the parameters used by the Swiss army to choose the Luger was "Speed - measure of the initial speed, 5 shots per weapon" http://www.luger-genesis.com/luger_h...e_specs_5.html Today we have chronometers, but how was such a measurement done over 100yrs ago? Thanks, __________________ Wood grips are nicer!

12-14-2008, 08:47 PM	#2
JorgeO User Join Date: Nov 2008 Location: Brazil Posts: 28 Thanks: 1 Thanked 0 Times in 0 Posts	If the method was based in conservation of momentum, I've already found it. If not, I still would like to know how. Thanks! __________________ Wood grips are nicer!

12-15-2008, 07:56 AM	#4
JorgeO User Join Date: Nov 2008 Location: Brazil Posts: 28 Thanks: 1 Thanked 0 Times in 0 Posts	Alvin Ballistic pendulum - that could be the name of what I had in mind. http://www.wooster.edu/physics/lehma...b_6_Bullet.pdf __________________ Wood grips are nicer!

12-15-2008, 08:33 AM	#5
Steinar User Join Date: May 2004 Posts: 1,538 Thanks: 18 Thanked 36 Times in 21 Posts	Several ways to do this, but I guess the metod mention above was most likely used. As a kid, I found out the speed of my Daisy Winchester pellet gun by shooting at a dry tree with the help of my dad clocking the time from the bang until we heard the impact. With a distance of 83m, we knew that it would take the 1/5th of a second for the sound to reach us. And by that I found a fairly accurate estimate JorgeO, DVD was sent today btw __________________ Previously known as Morgan Kane

12-15-2008, 10:56 AM	#6
John Sabato Lifer Lifetime Forum Patron Join Date: Jun 2002 Location: The Capital of the Free World Posts: 10,156 Thanks: 3,003 Thanked 2,308 Times in 1,098 Posts	The book that well documents the ballistic pendulum and many other ballistics-related procedures well is: Hatcher's Notebook, by General Julian S. Hatcher... who was one of the big wheels in the U.S. military armory system in the early part of the 20th century. Julian Hatcher retired as a U.S. Army major general, ...was a technical editor for The American Rifleman, and author of Machine Guns, Pistols and Revolvers and Their Use, and Textbook of Firearms Investigation, Identification and Evidence. He was director of the National Rifle Association from 1922-1946 http://www.amazon.com/Hatchers-noteb.../dp/B0007FHLUK __________________ regards, -John S "...We hold these truths to be self-evident that ALL men are created EQUAL *and are endowed by their Creator* with certain UNALIENABLE* rights, and among these are life, LIBERTY, and the pursuit of happiness..."*

12-14-2008, 09:37 PM	#3
alvin User Join Date: Jul 2007 Location: US Posts: 3,843 Thanks: 132 Thanked 729 Times in 438 Posts	Ballistic pendulum.... I assume.

12-15-2008, 11:04 AM	#7
JorgeO User Join Date: Nov 2008 Location: Brazil Posts: 28 Thanks: 1 Thanked 0 Times in 0 Posts	- Morgan Kane You can improve your method nowadays! http://arxiv.org/pdf/physics/0601102 Thanks for the DVD! - John Sabato Thanks for the book and link! __________________ Wood grips are nicer!

12-19-2008, 07:12 PM	#8
unspellable User Join Date: Jun 2002 Location: Iowa Posts: 768 Thanks: 0 Thanked 19 Times in 11 Posts	The method originally used to measure the velocity from the Luger involved the bullet severing two metal foil strips placed about 15 m or 50 ft apart. The foil carried a current. When the first strip was severed it interrupted the current to an electromagnet releasing a weight. The second strip on being severed induced a spark that marked a tape pulled by the falling weight. The method was actually quite accurate. One should bear in mind that what was actually measured was the average speed from around 5 feet to 55 feet. (The same method was used in both metric and English unit countries, 50 ft between strips in English countries pistols, 100 feet for rifles.) It's more accurate than the ballistic pendulum. I did the ballistic pendulum thing for my project in my first college physics class. I suppose that's giving away my age. Fancy dragging a big bore revolver into the physics building these days!