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Speed of ejecting brass from a 1911??

1245A Defender

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there is nothing special about a pic of a juggeler with several balls in the air, and your pic is no differant.

i want to say, that is a WAY good pic!:celebrate
the brass is pretty sharp so high shutter speed.

try setting up the camera at exectlly right angles to the brass tragectory, then snap pics at 1/10sec, figure the length of the blurred brasses flight to multiply out the FPS.

ive been into photography since 1969, the real kind, want to buy a color enlarger, analyzer, drums, timers, etc, adnausium?? ive get EVERTHING...
 

Pace

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Man, either you are pissed or taking a dump.

On a serious note, confused about your thumb and forehand placement. Maybe its the angle?

rolexbenz190e wrote:
This is the picture that I showed here and that I'm referring to in my posts:

DSC_0048.jpg

(yes its me in the picture, set the tripod up and set it on timer)

So as you can see, there are 3 pieces of brass in the air, and she couldn't fathom my camera being able to take a picture like that. For $1400, it better freaking be able to take a picture like that.
 

buster81

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The angle makes it tough, but based on that picture and these assumptions:

- you pulled the trigger three timeswithin 1 second

- the farthest piece of brass is about4 feet away

Does4 fps sound too slow?
 

1245A Defender

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buster81 wrote:
The angle makes it tough, but based on that picture and these assumptions:

- you pulled the trigger three timeswithin 1 second

- the farthest piece of brass is about4 feet away

Does4 fps sound too slow?
i applaud you for seeing the evidence in such pure terms.
im thinkin 1/2sec for,,,, bang, bang, bang, click the pic.
so i get 8 fps

the distance of the farthest brass, and the amount of time, are the variables.
 

buster81

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1245A Defender wrote:
buster81 wrote:
The angle makes it tough, but based on that picture and these assumptions:

- you pulled the trigger three timeswithin 1 second

- the farthest piece of brass is about4 feet away

Does4 fps sound too slow?
i applaud you for seeing the evidence in such pure terms.
im thinkin 1/2sec for,,,, bang, bang, bang, click the pic.
so i get 8 fps

the distance of the farthest brass, and the amount of time, are the variables.
Several years in engineering school were not a waste. Phew!
 

t33j

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A proposal for finding the approximate speed of ejected brass

Materials:
1 x firearm + ammo
1 x internet machine + microphone
1 x nerd with programming knowledge (Optional)
1 x video camera (or still with multiple exposure capabilities)
1 x length measuring device


Assumptions
The speed of the ejected brass is assumed to be low through a fluid with a low mass density thus drag is ignored.


Acquire the data:
Start a sound recording application on the computer, and verify it works.

Place a camera approximately in the plane of the muzzle of the barrel, approximately 3 feet to the side of the firearm that ejects the brass, and at a height that approximates the apex of the brass' flight. The objective of this placement is to minimize measurement errors from the imagery.

Place a length measuring device between the camera and the expected path of the ejected brass, minimizing the distance between the camera and length measuring device.

Set the sound recording application, and the camera to record.

Load one cartridge in to the chamber of the firearm.

With the firearm at a constant height, have an assistant measure the height of the ejection port of the firearm (Hf).

Fire the round

The assistant should mark the point of impact of the ejected brass and the floor. Record the Euclidean distance between the point of impact of the brass and the floor, and the location of the ejection port projected on to the plane of the floor. (Dimpact)

Make the gun safe, and stop the recording equipment.

Play back the video and record the height of the apex of the path of the brass (Hmax)

Calcumalations:
The law of conservation of energy states that energy is neither created nor destroyed, but can change forms.

The path of the ejected brass can be decomposed into its horizontal and vertical components.

The vertical component of the brass' velocity is found as follows:
At the apex of the brass' path, the brass has only potential energy (in the vertical component). The difference in energy between the time before it was ejected, and after it was ejected is calculated as E = mgh where m is the mass of the brass, g is the acceleration due to gravity (assumed to be constant in this case), and h is its maximum height above the ejection port (Hmax - Hf) as derived from Newton's laws. This energy was acquired as a result of the ejection of the brass from the firearm. That energy (kinetic) is calculated as .5m(Vy)^2 where v is the vertical component of the brass' velocity (Vy). Equating the two expressions for energy results in mgh = .5m(Vy)^2. The final result for Vy is sqrt(2g(Hmax-Hf)).

The horizontal component of the brass' velocity is found as follows:
Distance can be expressed as speed multiplied by time. The distance traveled by the brass in the horizontal direction is denoted as Dimpact as calculated previously. The amount of time the brass took to travel this distance is approximately equal to the difference in time between when the firearm was discharged and the time the brass impacted the floor. This can be found by noting the difference in time between the loud bang and soft ping in the sound recording. Record that value as T. The horizontal component of the brass' velocity is then found to be Vx = Dimpact / T.

Combining the two components of the brass' velocity is accomplished by taking the square root of the sum their squares (Pythagoras). Vtotal = sqrt( Vx^2 + Vy^2 )
 

t33j

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actually Vy could be found from the time as well, and would probably result in a more accurate result due to the measurement error involved in finding Hmax
 

Carnivore

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rolexbenz190e wrote:
Her and I have gone shooting before cause she is my friend's girlfriend. Shooting isn't new to her, she just thinks shells fly at horrendous amounts of speed and that my camera couldn't take a picture of 3 consecutive shells lol. I tried explaining to her that if brass flew at 800fps, anyone who was hit by it could suffer fatal injuries. She stuck with her opinion.

Then maybe let her shoot, and you stand aside and catch the brass, or do the math and load a casing in your muzzleloader with a predetermined load of powder charge in front of a sabot and shoot the brass at a target at 800 FPS. then explain to her the difference of visual contact with the brass when caught from an ejection port verses no visual connection with the brass when shot from a muzzleloader down range. then really shut her up and send her over to the guy that loves numbers more so than cameras and guns..

http://en.wikipedia.org/wiki/Mach_number
 

Bebop

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That may work but I have an idea for a simpler solution.

Items you will need.

Firearm

Camera that takes video or rapid succession pictures with a know rate (i.e. x number of milliseconds between pictures, or x FPS (frames per second) rate)

an object of known size or create a scale somewhere in the frame. Ever see mythbusters when they show high speed camera footage near that black and white board that is a scale of know distancebetween the sections of black and sections of white.

Set the scale asclose to the ejector port as possible and try to set up the scale bar so it is aclose to parallel with the ejecting brass pathas possible.Start the camera fire off a few rounds. Then take the distance that the brass travels between frames and multiply that out.

Example if the brass moves 6" between frames and the camera can take a picture 2 times a second then you have brass that ejects at 1 FPS.
 

t33j

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Bebop wrote:
That may work but I have an idea for a simpler solution.

Items you will need.

Firearm

Camera that takes video or rapid succession pictures with a know rate (i.e. x number of milliseconds between pictures, or x FPS (frames per second) rate)

an object of known size or create a scale somewhere in the frame. Ever see mythbusters when they show high speed camera footage near that black and white board that is a scale of know distance between the sections of black and sections of white.

Set the scale as close to the ejector port as possible and try to set up the scale bar so it is a close to parallel with the ejecting brass path as possible. Start the camera fire off a few rounds. Then take the distance that the brass travels between frames and multiply that out.

Example if the brass moves 6" between frames and the camera can take a picture 2 times a second then you have brass that ejects at 1 FPS.
I guess that'd sorta work. Although you'd only be measuring one part of the horizontal component of the velocity. There'd also be the same type of measurement errors. The timing can be done very accurately, and I think it would provide the most accurate solution.
 

fully_armed_biker

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Since the average 230 grain round leaves the barrel of a 1911 going somewhere around 1200fps, I think the 800fps estimate by your friend of a casing being ejected aren't even in the same zip code, let alone the ball park...ifa casing left the ejection port going 800fps, taking into consideration thedrag, angular velocity, etc...ifan ejectedcasing stayed airborne for a second, it would still land several hundred feet away...
 

marshaul

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rolexbenz190e wrote:
long story, but for the life of me I can't find any information on this. I want to know how fast does brass eject from a 1911 .45? In FPS...
This depends primarily on the extractor tension.

http://www.m1911.org/technic2.htm

The best way to check tension is with one of these and a set of these.

Folks say that, ideally, you want something like a pound and a half of extractor tension. Nearly everyone qualifies that by suggesting that trial-and-error is always necessary to fine tune it just right.

I, personally, set my extractor tension rather low. This has the nice benefit of consistently dumping brass about 2 feet to my immediate right: none of this brass flying all across the range. In order that my extractor maintain sufficient tension for proper function while starting at such low tension (most extractors slowly loose tension over time, not being made of spring steel), I use a C&S spring steel extractor which basically never loses tension.

I'm pretty knowledgeable when it comes to 1911s, so go ahead and send me any PMs if you like.

As for your ACTUAL question, the speed is impossible to answer without measuring the individual gun in question.

Mine spits brass in what can only be described as a lazy arc. Many people feel more confident with the aggressive flinging that seems to be the more common way to tune.
 

marshaul

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rolexbenz190e wrote:
Any one want to do any of these tests for me?  You know, since I did write that review for all of you about the Ranger T vs. Golden Sabre hehe.
Send me your gun and I'll set a chrony next to the ejection port. :p

I could tell you what the speed is for my gun, but I absolutely guarantee you that it's way less than most 1911s.

Or, buy one yourself:
http://www.opticsplanet.net/shooting-chrony-chronograph-23100.html

t33j wrote:
A proposal for finding the approximate speed of ejected brass...
Dude, just use a chrony. :)
 

rolexbenz190e

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Alright, i will settle for the ejection specs for YOUR gun Marshaul. Since you have a chrony and all... Just let me know what the make, model, and caliber of your gun is. use a .45 if you can get your hands on one. Thanks!
 

t33j

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lol I couldn't sleep and needed something to do.

Not everybody has a $80 chronograph.
 

marshaul

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rolexbenz190e wrote:
Alright, i will settle for the ejection specs for YOUR gun Marshaul.  Since you have a chrony and all... Just let me know what the make, model, and caliber of your gun is.  use a .45 if you can get your hands on one.  Thanks!
Well, there's a couple problems with that. First of all, I don't own a chrony, so I'd have to borrow one.

Secondly, I'm a little behind on the bills, so to speak, and I haven't been going to the range much in the first place, lately. :(

When I suggested that I would chrony my own gun, I was only half serious: I could do it, but it's not going to happen any time that's convenient. I was really attempting to underline the point that ejection speeds vary wildly.

Do you have a video camera? If you can shoot some video at a known framerate, say with a ruler in the frame, I could estimate the speed in a matter of seconds.

That's probably the cheapest way. In fact, it's the way I would probably determine the ejection speed of brass for my gun, had I actually financial motivation to go shooting this week. :?

A chrony would simply be the easiest and fastest. Too bad it looks like none of us wants to afford one right now. :D

t33j wrote:
lol I couldn't sleep and needed something to do.

Not everybody has a $80 chronograph.
Indeed. I don't even have one, and here I am suggesting the use of it. :p

I really want one, though. It's high on my list. From my experience with them, they're incredibly useful for a serious shooter.
 

marshaul

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rolexbenz190e wrote:
So, since I know that the picture isn't photoshopped, I know that my camera is capable of it. But she is under the impression that brass flies out of guns at 800fps. If that were the case, I don't think my camera could catch 3 brass in the air.
A heavy, low-pressure .45 ACP travels at speeds hardly any faster than 800ft/s. (See wikipedia.)

Ask your friend, can she see the bullets propelled by such a cartridge? Can she photograph them without the use of strobes fired by complex trigger systems?

This should be sufficient to prove that the brass cannot be traveling at anything like 800ft/s, which is the low range of the velocity of the bullet itself!

You simply can't see anything that small moving that fast. If I remember correctly, bullets have to be moving about 300ft/s before they can be seen(?).
 
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