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Old July 19, 2013, 01:50 AM   #1
Fingunner
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High speed handgun pictures

We've been doing some high speed photography on bullets leaving barrel and though you'd be interested seeing them:

Benelli MP90 .22LR, CCI standard:


STI EDGE 9mm, Magtech 124gr FMJ:


There is really high volume spray of powder residue in 9mm, almost like shotgun..

More high speed stuff in high res:
http://kuulapaa.com/home/highspeed.html
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Old July 19, 2013, 12:38 PM   #2
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Wow, excellent first post! Welcome, and thanks for the photos.
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Old July 19, 2013, 01:13 PM   #3
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Looks very cool! Welcome to TFL.

Bottom photo is interesting to me. It looks like the projectile is not well aligned with the barrel, and is pointed significantly downward. Compared to the straightline flash you can see all the way across the photo out of the barrel, the projectile is substantially out of alignment.

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Old July 19, 2013, 02:07 PM   #4
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That's pretty cool.

On the Magtech ammo, have you tried any other 9mm fodder to see if the unburnt powder is typical or is it ammo specific?
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Old July 19, 2013, 02:11 PM   #5
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Quote:
Bottom photo is interesting to me. It looks like the projectile is not well aligned with the barrel, and is pointed significantly downward. Compared to the straightline flash you can see all the way across the photo out of the barrel, the projectile is substantially out of alignment.
I noticed that too. The bullet looks canted down quite a lot.
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Old July 19, 2013, 02:34 PM   #6
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wish i had a highspeed camera to play with.

Great Shots
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Old July 19, 2013, 02:52 PM   #7
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Fingunner,

Can you also tell us what kind of photog equipment you used? Great photos!

Lou
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Old July 19, 2013, 04:33 PM   #8
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Yeah, these are great pics... Thanks for posting.

Now I see why the floor in front of indoor range bays is always so dusty.
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Old July 19, 2013, 04:40 PM   #9
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It looks like the projectile is not well aligned with the barrel, and is pointed significantly downward. Compared to the straightline flash you can see all the way across the photo out of the barrel, the projectile is substantially out of alignment.
This is a well-known phenomenon in ballistics. Bullets generally leave a rifled barrel with a longitudinal wobble that causes the nose and tail of the bullet to travel in a slightly helical path once spin is taken into account.

The reason this occurs is that, in the real world, barrels are never perfectly straight, bullets are never perfectly concentric, and muzzles are never cut exactly perpendicular to the bore axis. More precise construction can minimize these problems but never eliminate them.

However, if the bullet is close to concentric and the rifling twist is correct, the bullet will stabilize and assume a straighter attitude as it travels. This is the reason why some firearms- most notably rifles optimized for long-range precision- will often shoot more precise groups at long range than at short range, e.g. a rifle may consistently shoot 1.0 MOA @ 300m when it only shoots 1.5 MOA @ 100m.

One thing I found interesting about the photos is how little the STI's slide and barrel move between photos #3 and #4. It may seem like the slide of a 9mm pistol moves quickly, but its velocity is pretty slow compared to the bullet!

(OTOH I believe the Benelli MP90 uses a separate bolt rather than a slide; what appears to be the slide/frame interface is actually a cosmetic line on the side of the barrel shroud, which is why no movement is apparent.)
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Old July 19, 2013, 04:58 PM   #10
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Quote:
Bullets generally leave a rifled barrel with a longitudinal wobble...
Footballs leaving a quarterback's hand must also show some odd angles in the first milliseconds... very interesting...
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Old July 19, 2013, 05:04 PM   #11
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Welcome to the forum Fingunner, great photos.
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Old July 19, 2013, 05:31 PM   #12
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Quote:
This is a well-known phenomenon in ballistics
it's called precession: The motion of the axis of a spinning body, such as the wobble of a spinning top, when there is an external force acting on the axis. IIRC, spinning too fast will cause or magnify this. Too little spin will result in tumbling. It would be very educational to see hi-speed video of this.

Quote:
Footballs leaving a quarterback's hand must also show some odd angles in the first milliseconds
And often the whole way through the air.
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Old July 19, 2013, 06:26 PM   #13
g.willikers
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Yes, great pictures.
Thanks and Welcome.
Arrows show this effect real well.
When they leave the bow they wiggle and yaw so much, it appears that they couldn't possible hit the target.
But they settle down and go straight within a few feet.
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Old July 19, 2013, 06:37 PM   #14
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Fun photos.

Welcome to The Firing Line.
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Old July 19, 2013, 07:25 PM   #15
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I knew all bullets would wobble, but I guess I didn't expect the magnitude of the distance it would do so would be so large.

It looks like it's way off, is all. A few frames later it might be wobbling upward at an equally awkward rate, I imagine.

But, that's what high speed photography is all about - capturing the little details that pass by nearly instantly for us.

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Old July 19, 2013, 08:25 PM   #16
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The material ahead of the bullet is part of the precursor wave. It comes from two sources - any fouling/unburned powder/powder ash from a previous shot; and gas that escaped around the bullet both before the bullet moved into the rifling and gas that leaked around a jacketed bullet that doesn't quite fill the grooves.

The .22 bullet has less debris ahead of the bullet because being soft lead, it expands quickly, closing off the gas and filling the grooves.

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Old July 20, 2013, 12:29 AM   #17
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Thanks guys.

They're taken with high speed flash and it allows to photograph what happens in one millionth of second. There is option to tune picture also by 1/1.000.000 second steps. This won't make much sense though because even if we consider primer ignition and powder burn pretty consistent they actually aren't. I have noticed that there is roughly 15% variance (μs scale) when bullet exits barrel. The closer I want bullet to be the barrel, harder it is.

Setup seems to capture also pressure wave:


Bigger pictures:
http://kuulapaa.com/home/highspeed.html

Last edited by Fingunner; July 20, 2013 at 12:36 AM.
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Old July 20, 2013, 01:26 AM   #18
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Can you use a strobe to show movement or wouldn't it be fast enough?
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Old July 20, 2013, 01:48 AM   #19
Fingunner
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Yes and no, it can strobe >15 ms intervals and only max 5 times, which is far too long time for bullets. With ~50 μs intervals the power requirements would exceed component specs (and my power supply).
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Old July 20, 2013, 02:57 AM   #20
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wow,love to see a black powder shot
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Old July 20, 2013, 09:28 AM   #21
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Very cool pics.
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Old July 20, 2013, 04:42 PM   #22
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Quote:
I knew all bullets would wobble, but I guess I didn't expect the magnitude of the distance it would do so would be so large.
Only a couple of inches in this pic. The bullet is not stabilized in flight yet. The spin stabilizes it in flight.

Years ago Elmer Keith commented on how his loads for the 44 Magnum would penetrate deeper into railroad ties laid side by side than rounds from a 30-06 rifle would at 20 yards distance. He thought it an oddity.

Years earlier Julian Hatcher had explained the phenomena. The army had experimented shooting the 30-06 at various distances through various objects. They got more penetration at 50 yards than at 10 or 20.

Elsewhere on the interwebs there are vids of bullets leaving the muzzle, You can clearly see the wobble.

Excellent pics as always Fingunner!

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Old July 21, 2013, 02:07 AM   #23
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Very cool. Thank you.
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Old July 21, 2013, 02:07 PM   #24
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Very nicely done!

Particularly impressed with seeing the pressure wave too
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Old July 21, 2013, 05:39 PM   #25
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Cool, thanks. I appreciate seeing all the goings-on at the muzzle.
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