An Odd Question

[evanbaines]

Hey gang:

I have a weird question here I would like some help with.

I am a pro photographer in Nashville who does a fair bit of firearms photography (Sabre and Barrett are both clients). I am looking to do a portfolio shoot with my Kimber CDP 4" where I would like to try to capture a picture of the bullet as it exits the barrel of my pistol.

*NOTE: I am a former operator from 5th SFG(A) and have a very good handle on firearms safety. This photo shoot will be executed under carefully controlled and safe conditions.*

**Also note: I admittedly know nothing about the finer points of hand-loading, and would be relying on an experienced hand-loader to actually create these rounds.

The problem is that for technical reasons, my strobe lights have a limited ability to stop the motion of something as fast as a bullet. A standard .45 rd with a muzzle velocity of 800 FPS will move more than a quarter of an inch during the duration of the 1/40,000sec flash (IE 1/4" blur in frame) which is unacceptable.

I could rent a fancy custom high-speed strobe for $300/day to try to stop a standard bullet, but my question is whether there is any reason one couldn't hand-load an intentionally slow bullet? Ideally, if I could get it down to 200fps or slower, I think I could get something acceptable with the equipment I have. It seems like it would be a lot easier to get a friend with a reloading setup for .45 to make me some turtle rounds than to rent hundreds of dollars of gear.

My questions:
-Is there any safety issue I am overlooking as to why a round with a smaller-than-usual load shouldn't be used?
-Is there a formula by which we could estimate muzzle velocity for a given .45 load being shot from a 4" 1911 barrel?
-How slow can we make that round go (ideal would be 100fps or so).

[Brian Pfleuger]

You're major problem would be that 100fps, or even 200, is very close to "stuck in the barrel". However, doing the testing under controlled conditions with an experienced reloader who is not going to pull the trigger again with a bullet stuck in the barrel should be entirely safe. All that would have to be done is that the stuck bullet would be driven out of the barrel and the test retried. An experienced reloader should be able to pick a powder that would not have potentially bad effects at those levels. I've got to wonder though if producing enough pressure to push the bullet out of the barrel isn't going to produce more than 200fps by necessity.

[Unclenick]

Welcome to the forum.

This is a start pressure problem. The amount of pressure needed to start a jacketed bullet into the rifling of the bore will be enough to give it more velocity than you want. Think of it like pulling a tight cork from a wine bottle. You apply a lot of force and suddenly it lets go, going real fast.

I think the thing to do in this case is to fire a bullet at very low velocity (still too fast for the photo) into a row of plastic jugs filled with water. See if you can recover one that has not deformed too much to fit back into the bore? With some lubrication and the rifling pre-cut that way, you may be able to start it back into the bore manually, then use just a case and primer and no powder to propel it?

Another question is, how bright does the light have to be? If you have a strobe you can take apart and replace the main discharge capacitor with one that is a non-inductive type and five times smaller, you may well get a dim flash of about five times shorter duration? Most commercial strobes use electrolytic capacitors that aren't too quick off the mark and a capacity that takes some time to discharge through the flash tube's resistance.

An alternative would be to run a bank of LED's with, say, a one microsecond pulse. That could be done with a 555 timer. I don't know that the phosphor in the white LEDs will give you the speed you want, but an array of green, blue, and red LEDs might give you color close enough you could correct it in Photoshop? Be cheap and all Radio Shack parts if it can be made to work OK? I used to trim overshoot out of high speed optical detectors with a short LED emission like that. Gave good, quick square wave output with leading edges in the fractional microsecond range. Probably limited more by what I drove it with than by the LED itself.

[kraigwy]

Its doable. I've loaded 45s to about 168 fps. It was not very consistant, I was using 231,

However I think you could get more consistancy using Trail Boss. Light loads of Trail Base would fill up more space giving you more consitancy.

You just have to play with it a bit.

[InigoMontoya]

Are you trying to get a picture of the gun or the bullet or both?

My point being that if you're trying to get a picture of only the bullet you may be able to gin up a synchroballistic mirror. Done right, they're expensive and all that, yes, but given the cheap cost of a .45 you could make a cheapo that simply ran full time (zero triggering), shoot a bunch of pics, and one of them ought to be dead nuts on (or close enough).

Using this approach your background and the gun might move 1/4", but your bullet would be frozen (except rotation.... Hmmm... how much does it rotate in 1/4"?).


(Plus, it would be useful for all sorts of similar shots...especially if you built up a triggering circuit.)

[Jim243]

Rent the camera!! What's the fastest shutter speed on your equipment? You could rig a sound activated switch to fire a bank of flashes that are delayed by a milisecond that would be an interesting photo of the same bullet traveling down it's path. If your shutter is not fast enough just leave the shutter open (time laps) in a very dim or dark room and let the flash unit fire as you pull the trigger (still need a sound activated switch).


Remember you are going to get a muzzle flash so keep your F-Stop down as far as it will go (it will not give you too much depth of field, just make sure your focus is tight and sharp) And for pete's sake keep out of the path of the bullet.


Good Luck
Jim

[Dis-1-Shooter]

Evanbaines, my chronoed plinker load is Win 230 gr bullet, 4.7 gr HP38, CCI large pistol primer and 1.240 OAL from a 3" Kimber Ultra will produce 530-550 FPS. With an extra inch in your barrel, in theory, it should be 100 FPS faster and so on. You could play around with the charge and seating depth and achieve faster/slower FPS, or take the easy way out and just photoshop it. Hope this helps.

[InigoMontoya]

Regarding scaling rounds/barrels up/down in areas that are off the reloading chart....

A couple rules of thumb that I've found work reasonably well. Mind you, the loading I tend to do is for very large guns - not handguns - so they may not hold true. HOWEVER....


Assuming you have a known load and muzzle velocity....

Changing the barrel length will scale with the square root of the ratio of the new barrel length to the old one. In other words, if you double the length of the barrel, your muzzle velocity will be sqrt(2) = 1.4 times as fast. Similarly, if you halve the barrel length, it will be sqrt(1/2) = 0.7 times as fast.

Or... Keeping all else equal but changing the powder charge, the muzzle energy will scale linearly with the charge mass. You'll have to back out muzzle velocity from the energy numbers.

Again, this is stuff I use for large guns. It's not perfect, but for it's simplicity it works surprisingly well. Will it work for small guns? I've no idea, but I present it for thought (perhaps it will help you zero in on your turtle load faster).

[InigoMontoya]

@Jim,

If he's going to rent a camera, he may as well rent something like a Photron. Voila, no flash required. Just do it in broad dayling and get full motion video at 20,000 frames per second (and insanely fast shutter speeds).

[griz]

I've seen velocities below 300 FPS with extremely light charges and lead bullets. But they were so slow that they had a "bloop" sound like a pop gun. If you tried the same thing with jacketed bullets I don't think it would get out of the barrel.

Anyway, for some perspective, 100 FPS is slower than a good fastball.

[evanbaines]

Wow, you guys are hugely helpful. Its going to take a bit for me to digest all of this info, but I'll come back if I have more questions.

RE: The photography stuff
For this kind of photography, the shutter speed of the camera is largely irrelevant. Most normal cameras only go as fast as 1/8000 of a second, which isn't even close to bullet-stopping territory. Usually, this will be done in a dark setting (IE outside on a private range at night) with strobes. A normal hotshoe strobe will go as fast as about 1/40,000 sec duration on low power, which is good enough for a lot of things but really not up for stopping a full-speed bullet. I really need 1/1,000,000sec durations, but strobes that do that and still have a reasonable amount of power are tough to find. I'm going to need at least f/5.6 to get enough depth-of-field even with a tilt-shift, and would prefer to keep my sensitivity 1600 or (preferably) less. I am going to test this weekend to see how bright the muzzle flash is: I will need at least enough light from the strobes to balance with the muzzle flash. I will be using something like this: as a triggering device. http://www.universaltimer.com/

I would like to actually capture both the gun and round, with the round just having emerged from the barrel.

Since its a subsonic round, it seems like I might be able to use an audio trigger (it hears bang, and flashes after a pre-programmed delay)... but I may have to find other options like the IR beam if that doesn't work. Again, all of this will be easier if I can slow that round down a ton.

I am not nearly proficient enough with electronics to make much headway with a DIY strobe... But I'm looking at the possibilities of sourcing one from someone who is that proficient.

[Scorch]

Am I missing something? Sorry if it sounds like I am challenging you, but a bullet moving at 800 fps will move .02" in 1/40,000th of a second (20 thousanths of an inch, not 1/4 of an inch). Try it, see if it works before saying it won't.

[Brian Pfleuger]

Am I missing something? Sorry if it sounds like I am challenging you, but a bullet moving at 800 fps will move .02" in 1/40,000th of a second (20 thousanths of an inch, not 1/4 of an inch). Try it, see if it works before saying it won't.

1/4 inch in 1/40,000 of a second would be 10,000 inches per second. 10,000 inches per second is 833.34fps.

I think you divided your fps by 12 instead of multiplying.

[evanbaines]

Not a math genius here, so I may be screwing something up here, but:

800 fps = 9600 inches per second.
Multiply by 1/40,000 = .24 inches per 1/40,000 sec

[zippy13]

For a different approach, does it have to be a "real" metallic bullet? A wax or plastic bullet can be easily driven a low velocity with just primer force.

[l98ster]

How about this:

Swage a bullet down .005 smaller than the diameter of the barrel. Use a snub nose revolver. You might actually get a lead bullet out of the barrel with just a primer!! It could be like a .357 colibri!!!!

I would assume this technique may be successful with an autoloader as well. For a still shot, cycling the gun doesnt matter. Just use more lube than usual. With a bullet swaged so much smaller than the barrel, this might work.

-George

[Tex S]

You will hafta post that pic if you get it.

Good luck!!!

[InigoMontoya]

Several thoughts....

I still think you might have fun renting a Photron SA5 (link), but I acknowledge it may not be up to the resolution you're after.... You didn't say what your desired media is. I mean, is this for a webpage? A magazine article? 8x10 glossies? Posters? Billboards?

----------------

I wonder if a synchroballistic mirror could be married to an off the shelf strobe. More to the point....

Imagine a strobe enclosed in a box that only has one opening. In front of that opening is a small mirror that's spinning very fast(*). When your strobe lights, the mirror sweeps a beam of light across the gun and bullet. Since your subject depends upon reflected light, if the mirror isn't in the "right" orientation any light coming off the strobe is irrelevant as it goes elsewhere. Thus, a 1/40,000th strobe may only illuminate the subject for 1/400,000 of a second (or whatever).

I actually have little doubt that this would work from a timing perspective. The question is whether or not your camera would gather enough light for a good pic given that it will now only be gathering a small fraction of the light emitted by the strobe.


(*) A prism may actually work better, but it's easier to visualize with a mirror.

-------------

Zippy has an interesting thought regarding non-standard bullet composition. What if your bullet had a deeply hollow base. Think: exagerated Bridgeman cup. Such a bullet would be much lighter but retain all outward appearances of a normall bullet. Further, since it's structure is significantly altered, it would probably be pretty easy to remove from the barrel should it become lodged.

[SatCong]

Spent the better part of 30 years as a Photog in the Nashville market, For just about any commercial situation, I've "BTDT".
I had good success in a dark, not darkened, but DARK studio using a mounted Hasselblad and Ectachrome 100, open shutter and a Monobloc strobe.
It gets LOUD and Smokey and you better be sure of your ability to arrest the fired bullet's progress. A large portion of the budget for that shoot (pun intended) was the construction of a frame that held about four feet or so of thickness consisting of bagged river sand, layers of wetted old phone books and 2 hefty 4x4 foot x 1/4" steel plates (a very busy Elm Hill Pike was on the other side of the front studio wall). The assistants EARNED their money on that occasion!
Today, if I was still shooting freelance, I would photograph the weapon firing a blank load to get the fire/blast captured. Then I would photograph a proper bullet, static. Then use the magic of P'shop to get the effect.
Paying clients will be more willing to minimize the day rate for the photographer and pay the lesser "file manipulation" hourly fee for P'shopping the two images together. This approach will yield more repeatable results and let you bracket exposures and finesse the static shot lighting changes, once your set-up gets the AD's sign-off.
Oh, and all digital these days, of course.
Man, if I had an inkling of the way things would change while I was spending all my GI Bill money at Brooks Institute in the late '70's, early '80's !

Good Luck, Be Safe!

SatCong

[PCJim]

Trying to accomplish something along this line? I use this one as a background image.....

S&W 4506 firing

[SatCong]

That's a nice P-shopped piece, but where's the slide movement?

SatCong

[mapsjanhere]

Get the lightest 44 bullet you can get your hand on and have it loaded on top of just a primer. If it comes out of the barrel, you got your shot. So the aficionado will most likely recognize the lack of rifling imprint on the bullet.