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It will be nice to see some actual tested theories for a change. We've just been wandering through this hobby with no guidance or theories to what to shoot. I use old condoms for bands because I have no idea what I'm doing.
Don't use the ones you find on the beach. The sand is bad for them.
[/quote]

I'll just take your word on it. You've been right so far.
 

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Discussion Starter · #203 ·
If you are following the Slingshot Forum 300 Club Topic, you already know that I have achieved 354 fps with pseudo tapered Dankung 1842. Here's the formula for making a set of these bands.

Overall length of each tube = 11 inches. Measure 7 inches from one end and fold that end back on the 7 inch point and tie the end to the tube. The overall length will now be 7 1/2 inches. Use the extra 1/2 inch to tie on the pouch. Here's a link to a tutorial.

file:///home/henry/web/oldpeddler/biombos/bandset-1842/index.html

I also now have a supply of 1745 tubes and will duplicate the tests made earlier on 2040 and 1842 in the near future.
 

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yesterday we have shoot the fresh arived 20/40 and 18/42 tubes! we tapered like Henry recommend it. i have to say we are all very lucky with this tapered tubes! the efficiency is not like TB but the speed is very good! 8mm with 95 - 100 mps and 10mm with 83 - 85 mps also they are very quiet and last much longer than the bands. my favorite for smal bullets for sure.

the only problem: the loop slipped! not only mine every loop sipped! we made even two constrictor knots! was better but still sipped. we stretch the tubes to the very end maybe this is not good with tapered ??

take a look at the pics, this is how it looks after the shootout last night! it wasnt 7:6 any more

it slipped 6cm.

but all in all i am happy with this tubes.

Wood Water Flooring Floor Hardwood

Ruler Office ruler Measuring instrument Natural material Font
 

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Discussion Starter · #206 ·
yesterday we have shoot the fresh arived 20/40 and 18/42 tubes! we tapered like Henry recommend it. i have to say we are all very lucky with this tapered tubes! the efficiency is not like TB but the speed is very good! 8mm with 95 - 100 mps and 10mm with 83 - 85 mps also they are very quiet and last much longer than the bands. my favorite for smal bullets for sure.

the only problem: the loop slipped! not only mine every loop sipped! we made even two constrictor knots! was better but still sipped. we stretch the tubes to the very end maybe this is not good with tapered ??

take a look at the pics, this is how it looks after the shootout last night! it wasnt 7:6 any more

it slipped 6cm.

but all in all i am happy with this tubes.

View attachment 28466
View attachment 28467
Here is a closeup of one of my ties. Tubes are 2040, sleeve is 1745, string is waxed leather lacing twine. Use moderate stretch and tight tie. I stretch these until they bottom out and have never had one slip. Hope this helps.

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To tie a loop for a taper I use what looks like a leather washer: a 0.75 inch diameter piece of leather (similar to pouch leather) with a 0.25 inch diameter hole punched into it. This leather washer is located at the junction of the looped and single tube sections. One end of the hole in the washer is connected to the single tube that goes to the pouch. The opposite end of the hole in the washer is connected to a folded-in-half single tube that becomes the loop when the 2 ends of the folded tube are fed together into the hole in the washer. I've been using soft cotton thread to tie Body jewelry Twig Jewellery Wire Metal
the tube ends. I find this gives rather precise control over the length of the looped section and is easy to reproduce (e.g., so that both sides of the slingshot have very nearly the same length of their looped sections). I had trouble getting this control with the method described by Tobse, which otherwise worked well and is easy. Another advantage of the leather washer method is that it allows use of different types of tubing in the single and looped sections. For example, it can be beneficial to use 1745 in the single section and 2040 in the loop section. I've attached a picture.

The method shown by Henry recently also looks attractive, but I had a devil of a time trying to get the sleeve tube in place-- maybe wider forceps or forceps with a more wedge-shaped tip would have helped.
 

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Discussion Starter · #210 ·
The method shown by Henry recently also looks attractive, but I had a devil of a time trying to get the sleeve tube in place-- maybe wider forceps or forceps with a more wedge-shaped tip would have helped.
I use small pointed forceps. I put the sleeve over the forceps, open them and feed both ends of a string looped over the loop I want to secure. Then I can pull the rubber through the sleeve easily. I'll try to get some pictures of the procedure tomorrow.

I have got sidetracked from the promised 1745 tests, but will try to at least do some tests on a looped 1745 set tomorrow, so we will have a base comparison with 2040 and 1842.

In the meantime, I've been trying a hybrid configuration consisting on one loop of 1745 at the fork and a loop of 2040 at the pouch, using the same 7:6 ratio. Details here - http://slingshotforum.com/topic/19795-1745x2040-tapered-tube-set-open-source-project/page__st__10#entry239068

This afternoon, I managed lots of 280+ fps, maybe a half dozen 290+ fps, and one 304 fps with this setup. I also made a similar set using 1842 and 2040. Tomorrow I'll modify another frame to test that setup. I also plan to make a bit longer set of whichever proves to be fastest to try on my Starship.
 

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OK, I know that some of you guys are bored with all the discussion of lb/ft, because velocity is where the glamour is. So here are the results so far, of velocity measurements, from which the energy figures were derived. Note that with 39.7 grain .30 cal lead, pseudo-tapered outperforms looped. The looped configuration doesn't show a clear advantage until projectile weight reaches 125 grains. (.429 lead) I'm guessing that the crossover point is about 100 grains, but don't have any 100 grain ammo.

View attachment 17181
These results make me thinking about my next order tubing.
 

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Looped 2040s are my favorite.
The set I'm using now starts with a 13" length on each side so after looping and tying I get about 6.25" effective length.
With my 31" draw these will send a 7/16" steel ammo through a free-standing Coke can at 35' so fast that it goes through and almost doesn't knock the can over. I don't have a chrony but that's fast!
Super-smooth and easy draw as well.
That set Jim is talking about with the heavy pull is what I shot my scored targets with at the ECST. They're fast but brutal, even at a longer length. Very unusual for 2040s.
I never thought that 2040 can be that powerful. My head is spinning now.
 

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Discussion Starter · #214 ·
Yesterday I finished a series of tests pitting 2040 vs 1842 vs 1745 in looped configuration. The tubes were each cut 14 inches long, resulting in a loop of slightly over 6.5 inches. Jim Harris' Performance Catapult pouches were used, and all shots were fired from my Cashew Fork Ringshooter.

A pdf of the results is attached. In the far left column is listed ball caliber and weight. Each group of 10 shots shows 5 shots velocity at an anchored draw of 32 inches, followed by 5 shots at my maximum draw. On the rows marked "Average" is the average velocity of each 5 shot group and the energy in foot pounds.

I believe that if I were a bit stronger, there would be a greater variation in velocity between 2040 and 1745, and to that end, I am going to repeat the tests with single tube per side in the near future. For now, these results tell me that with .44 lead, I can get essentially the same speed with 2040 as 1745. You younger, stronger guys can probably get more speed with 1745.

In my opinion, if you are shooting anything lighter than .50 cal steel/44 cal lead with any of these looped tube sets, you are wasting energy.

View attachment 2040-1842-1745.pdf
 

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Henry, I don't understand a f*ing thing you're saying. Just answer me this please: I am shooting 18-42 tubes at a 38-inch draw, using a very lightweight pouch. Is 45 cal. lead not a good match?

I know this is seemingly a disrespectful post. But it's really a personal question. I know Henry has the answer, but my hope is that he'll show us all how to get it in very clear terms. He's a guy who can put it that way.
 

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Discussion Starter · #216 ·
Henry, I don't understand a f*ing thing you're saying. Just answer me this please: I am shooting 18-42 tubes at a 38-inch draw, using a very lightweight pouch. Is 45 cal. lead not a good match?

I know this is seemingly a disrespectful post. But it's really a personal question. I know Henry has the answer, but my hope is that he'll show us all how to get it in very clear terms. He's a guy who can put it that way.
There is nothing in your post that I find disrespectful. Based on my results, and considering that you and I are probably fairly close in strength, looped 1842 with .45 lead is probably the most efficient combination for you. At that draw, you should be seeing about 210~215 fps and about 12.5 lb/ft energy with .45 lead.

As for how to find an efficient combination without a Chrony and a bunch of math and tables, here's how I would do it. Rig up OTT on a small frame with low forks, no matter what rubber you're using. If you get handslap with your chosen ammo, go heavier. If you don't, go lighter. If you are limited to one size ammo, change the band dimensions. When you find a combination that delivers good speed with very light, or no, handslap you're there. This method will not work with Ringshooters or TTF frames. Once you find the combination, you can switch to the frame you want to use.

I hope that helps.
 

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I would like to chime in to this thread and say thanks so much for your great testing Henry. I just recently got a nice order from dankung with 1745 and 1842 tubeing and i followed your guide for tube sizes and all i have to say is wow those suckers are fast.

This is a great thread and super usefull information. :bowdown: .
 

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Henry, I don't understand a f*ing thing you're saying. Just answer me this please: I am shooting 18-42 tubes at a 38-inch draw, using a very lightweight pouch. Is 45 cal. lead not a good match?

I know this is seemingly a disrespectful post. But it's really a personal question. I know Henry has the answer, but my hope is that he'll show us all how to get it in very clear terms. He's a guy who can put it that way.
There is nothing in your post that I find disrespectful. Based on my results, and considering that you and I are probably fairly close in strength, looped 1842 with .45 lead is probably the most efficient combination for you. At that draw, you should be seeing about 210~215 fps and about 12.5 lb/ft energy with .45 lead.

As for how to find an efficient combination without a Chrony and a bunch of math and tables, here's how I would do it. Rig up OTT on a small frame with low forks, no matter what rubber you're using. If you get handslap with your chosen ammo, go heavier. If you don't, go lighter. If you are limited to one size ammo, change the band dimensions. When you find a combination that delivers good speed with very light, or no, handslap you're there. This method will not work with Ringshooters or TTF frames. Once you find the combination, you can switch to the frame you want to use.

I hope that helps.
Very impressive, Thanks for sharing Henry! I definitely gonna try to make a set by myself. BTW, do you know that in China, there is a new concept of bandsets? My people in China call it 'cocktail band'. It's basically a combination of 2050 and 2060. I was told that it can easily achieve 300+ FPS velocity. I am thinking maybe sometimes you can test them, and find a way to achieve higher velocity, go slingshot! 3f0c602e93f7229c.jpg

here is the link http://www.dangongzm.com/product-140.html
 

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Yes, Shadow, some of our members are testing those kinds of hybrid tubes. I'll leave it to them because I shoot tubes almost exclusively in some form of loop. Thanks for the heads up.
Hybrid tubes! Thank you! Have they posted the result yet? Could you show me the link to the topics? I appreciate it very much! I am working on the loops now, based on your guidance. Hope it works! Thanks again!
 
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