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I just used my CombowSling to fire .50 lead ball, weighing 170 grains, at 210.4 fps. By my calculations, that comes in at 16.7 fpe. Whew! Looks like I get to play with the big boys. Video is loading onto Youtube ... will post the link as soon as Youtube says it is ready.

Now, where are those stinking badges????? :headbang:

Cheers ...... Charles
 

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All right, here is my video:


CombowSling

band length: 9.5 inches

slack length: maybe 1 inch at most

band material: some sort of latex tube ... came on this wonderful device

pouch: heavy, but flexible cow hide, 3 1/4 x 7/8 inches

my draw length with this setup: 42-43 inches

ammo: about .50 caliber lead ball, weighed on my digital scale at 170+ grains (cast with buckshot mold)

maximum velocity: 210.4 fps

measured velocities: 210.4, 206.5, 201.6, 203.1 all within 5% of each other

energy by my calculation: 16.7 fpe

Cheers ....... Charles
 

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I figure some of the younger, stronger guys are going to be showing us Old Geezers 50+ lb/ft in short order. Tobias has already shown us 80 lb/ft (100+ joules) and it won't be a big deal for him to repeat it. I see some exciting times ahead.

I want to caution everyone about the dangers at high power levels. A pocket pistol shooting .25 ACP generates about 65 lb/ft of muzzle energy. I think everyone will agree that a .25 ACP pistol is capable of killing, so if you are strong enough to pull a slingshot that can generate 50+ lb/ft, treat it with the same respect you would a handgun. Protect your fork holding hand and make sure your backstop will not cause ricochets. And get some good shooting glasses.
Hey Henry,

Yep on the comment about the younger crowd. I figured I had better get my oar into the water before the young turks completely swamp us!

And right on about the caution. Catching a .50 lead ball moving at over 200 fps is guaranteed to make you feel worse than uncomfortable ...

Cheers ..... Charles
 

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Nice job guys! Charles, there's a chance you may have been shooting faster than you think, I noticed you shot through the chrony in a downwards direction, that creates a longer journey in between sensors for the ball.. just a guess but 220 may possible with a flat shot..?! Cheers
Thanks, Ben. I probably was shooting a bit downward. I was still hitting my backstop up near the top. I tried to compensate by taking a really wide stance, but that was only partially successful. I was too lazy to get out a card table to raise my backstop up. I have some hopes of trying for a higher energy at a later date. But for now, I was just thankful to clear that first hurdle.

Now me lad, you have already done some outrageous performances. Time for you to give us all something to shoot for. Your temperatures down under ought to be conducive to some really high velocities this time of year.

Cheers ..... Charles
 

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I need 248 fps with the 44cal do-it mold lead balls to reach 15 ft/lbs. Right?
The only way you can be certain of ball weight is to weigh them. Your alloy can vary weight by quite a bit. I have two Do-It molds and my current batch of .44 balls (actual diameter .429) cast mostly from wheel weights weigh 116 grains. To make it easy, here is an an Excel spreadsheet that will do the math for you. It gave me 242 fps with my balls for 15.09 lb/ft.

attachicon.gif
AmmoCalc.xls
Do I need a special scale?
Postal scales work well.
Many postal scales are only accurate to .1 ounce, which is 43.74 grains or 2.83 grams. If you do use a scale of unknown accuracy, weigh 50 or more balls at once to reduce the error.
This is the scale that I use, and it is wonderful.

http://www.leevalley.com/en/garden/page.aspx?p=68352&cat=2,40725

It weighs in about any units you want. It has a tare function so you do not have to worry about the weight of the container. It is small and compact ... shuts off automatically when not in use. Great for weighing ammo.

Cheers .... Charles
 

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Hey Bean! That was some mean shooting! I had to laugh watching your eyes as you were stretching to do that full draw!!!! By the way, do your knuckles drag the ground when you walk??? :rofl: Yeah .... if we all had longer arms, we would all shoot a lot faster ...

Cheers ....... Charles
 

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Hey MJ,

According to at least one ball bearing manufacturer, 5/8 inch chrome steel bearing weighs in at 16.44 grams, which is 253.71 grains. You said 16.44, but in your write-up you gave it as 15.44.

http://americandad.biz/chromechart.htm

By my calculation that is 24.4 fpe. So the calculations on your phone app are consistent with the proper weight for that size of steel ball.

Cheers .... Charles
 

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O.K., thought I would give it another go with my CombowSling. For some time I have been saying that in the ranges appropriate for slingshots, heavier ammo generates more energy than lighter ammo, in spite of the decrease in velocity. Soooo, I went for heavier ammo. Those slugs in the video weighed on my scale at 232 grains for the lightest one. Here is the video:


The velocities were 191.3, 186.6, 188.4, and 184.0, all in fps, and all within 5% of each other. By my calculations, that gives 18.85 fpe. Just trying to claw my way off of the bottom. I think I just crawled past Henry, but to really move up, I am going to have to fabricate some other band arrangement.

Cheers .... Charles
 

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Note to Henry: I see you have changed my standing in the summary as follows:

Charles 18.86 lb/ft 25.57 joules 210.4 fps (BP lead bullets - 232 grains/15 gm)

I only wish I was shooting at 210.4 fps with those heavy slugs ... actually the top speed was only 191.3 fps. I will let you edit the entry.

Cheers ..... Charles
 

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Jeeeeeez... now I'm in a race for last place!

Congratulations, Charles, a fine demonstration of how slower can be more powerful.
Interesting to note ... Only one of the speed freaks results would qualify for the power rangers. In slingshot appropriate numbers, higher velocity does not always equate to more energy.

Cheers ..... Charles
 

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Enjoy not being last while you can, Charles. I just shot 19.66 lb/t - 213 fps with some 194 grain .45 cal bullets that I cast for my Colt 1861 Army. Now to set up the camera. I'm going for 20+. :)
ARRRGGGHHH!!! Just when I thought I could relax for a while! Go Henry! I am going to have to hustle to get into the 20 fpe range .... :help: :wacko:

We should have a new category .... fpe x age ... give us old guys a fighting chance!

Cheers ...... Charles
 

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Hmmm...

I was just playing with the power calculator and if I can get one of those 13/16" steel balls I have up to 180fps then I'm looking at 40 ft/lb.

Looks like I'm gonna need a wider pouch on the 'ship!

-Edit: I put a Rayshot "Rockstar" pouch on the set of bands I was using before on my starship. I stepped out the back door in 25 degree (F) weather and took a shot with the 13/16" ammo. It almost knocked my catchbox off the stand :). Will run it over the chrony at my earliest opportunity.
Yep MJ ... you got the right idea. You will get the most power by shooting the heaviest ammo you can propel at just over 180 fps ... 180 is the cut-off for Power Rangers.

Cheers ....... Charles
 

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DERN! Now there's one more in front of me!!!! Congratulations, MJ!

I may have to resort to what some of those old Brits used to do in Africa. When shooting those huge bore black powder rifles with AWFUL kick, they would get some poor black porter to put it to his shoulder while they aimed and fired!!! Now Henry, I note that you said the slingshot has to be held and fired by hand .... but you did not say whose hand had to do the holding and whose had to do the firing. Sooo, maybe if I use both hands to hold the blasted thing and get some young buck with strong hands to pull it back ...... :blink:

Cheers ..... Charles
 

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Way to go, Popedandy! No sweat on those early errors. It takes a little experience to figure out just where the ammo has to go.

Looks like there are now 3 of us that will have to arm wrestle for last place!

Cheers ...... Charles
 

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All right, folks. I thought I would try to make the Power Rangers with rubber bands. I was using Rubberbandguns #32 red rubber bands.

http://www.rubberbandguns.com/ammunition/ammunition-size-32-red

I braided them, from pouch to fork, in a 22223333 configuration. Note that when braiding, each rubber band is doubled in the middle. I first tried it on my mutant ninja, but my poor hands and shoulder would not let me take a decent draw on it. So I put some tabs on my King Cat and rigged the bands on that. The slack length was about 7.5 inches, and I was drawing at about 45 inches. It was windy and cool here today, but at least it was not raining. Sorry for the poor audio quality ... I positioned the camera too far away.


I see I miscalled some of the figures. I lubricated the bands with baby powder, and on my first shot the pouch slipped out of my hand because of all the powder. You can see the powder flying off at each shot ... or was that because my shooting was so smoking hot??? :rofl: So here are the relevant velocities:

180.9

181.2

181.4

My best velocity was 181.4 fps. I was shooting those old black powder slugs which weigh 232 grains. That gave me 16.9558 fpe, so just call it 17 fpe. That just goes to show that you can qualify for the Power Rangers with office rubber bands!! Some of you young guys without arthritis and good arm strength could do a lot better. Note that this was more power than I got with my Combow Sling shooting .50 caliber lead balls.

And what about that pouch??? So much for that wimpy a$$ kangaroo leather!

Well, I did not up my standing, but nobody else so far has qualified with office rubber bands! :naughty:

Cheers ........ Charles
 

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All right, everyone ... I just used Alliance Sterling #107 rubber bands to fire a 175 grain lead ball at 204.7 fps, giving me 16.3 fpe. I always said those bands may not be the fastest in the world, but they could carry weight! Video is loading onto Youtube as I type. Will post it when it is ready.

Cheers .... Charles

Well, the video loaded, and here it is:


The velocities were, in fps: 190.3, 204.7,198.4,199.6,197.3, and 202.9

The bands were just Alliance Sterling #107 office rubber bands. As you can see in the video, I put an extension on my King Cat because I was having trouble with my shoulder and my hand and could not draw back far enough. With the extension I had a draw length of 56 inches. The slack band length, fork to pouch tie, was 12 inches. I was shooting lead balls that weighed 175 grains on my scale. I decided not to fool with that kangaroo leather again, but instead I used a decent cow leather pouch that I would use for hunting. At my maximum veloicty, I was getting 16.3 fpe.

Again, this does not increase my standing with the Power Rangers. But it does show that you can qualify for the Power Rangers with office bands. I put an extension on the front of my King Cat to compensate for my physical limitations. But you young guys should be able to draw these bands out to full butterfly at 60 inches or so and do even better.

Cheers ...... Charles
 
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