# Chrony Test: Trumark Black Slower Than Red!



## calinb

I pulled the pouch to my ear (~ 32.5") and recorded the following average velocities at about 70F (and I'm not at all expedient with my release):

3/8" steel

Black--179 fps

Red--185 fps

Pocket Predator Standard 1" non-taper Gold Bandset (original long-ish length for good service life)--190 fps

I thought maybe the Black tubes would show their stuff with heavy ammo, so I tried 54 cal. lead balls cast from wheel weights

Black--146 fps

Red--153 fps

Hmm--the difference in speed was about the same, with Red still faster.

I guess Black is just for marketing purposes. They sure FEEL stronger (harder to pull) than Red (or Yellow)!

Also, I don't like the plastic pouch connectors used on the Black and Yellow Trumark tubes. Those rock-hard somes-a-breeches slap my hand something viscous when shot on my Rambone in OTT style! The slotted and looped tube to pouch tie method used on the Red Trumark tubes is much better.

Just FYI and FWIW (not that many forum members are likely to be using Trumark tube sets).


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## Alexander Holman

I actually use the Trumark red tapered tubes quite a bit. I can always run to the store and get a set or two if I need extras. I never have used the black tubes. The reds are about the best commercial bandsets out there, just wish they came with a better pouch.

Thanx for the numbers!

-Xander


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## calinb

Alexander Holman said:


> I actually use the Trumark red tapered tubes quite a bit. I can always run to the store and get a set or two if I need extras. I never have used the black tubes. The reds are about the best commercial bandsets out there, just wish they came with a better pouch.
> 
> Thanx for the numbers!
> 
> -Xander


I'm a fairly new SS shooter (well...new to the sport as an adult). The only tubes I have are the Trumark tubes and the tubes on a Daisy SS. I agree with you; the Trumark Red seems to perform well and, though I mostly shoot flat bands, I've yet to wear out any Trumark tubes. I just haven't read reports here in the forum of shooters using them. It's great to hear that you use them and maybe I saved you the expense of buying a Black set. Luckily I bought three Red sets and only one Yellow and one Black--just to try them. I would buy the Red sets again but pass on Yellow and Black.


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## Imperial

i also use the trumark reds . the black ones have their purpose, yes they are harder to pull, they seem to last a long time, and once they break in, watch out ! imo- the blacks are more for people with short draws and want impact over speed. they are great for hunting small game with.


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## calinb

Imperial said:


> i also use the trumark reds . the black ones have their purpose, yes they are harder to pull, they seem to last a long time, and once they break in, watch out ! imo- the blacks are more for people with short draws and want impact over speed. they are great for hunting small game with.


I'm not sure what you mean by impact (momentum, kinetic energy...?) But yes--that's what I thought Black was for too. When these parameters increase with higher mass projectiles it is at the expense of speed. That's why I tried the 54 cal. lead ball. There are not many people regularly shooting ammo heavier than that! Even so, Black still measured slower than the Red with the same heavy lead projectiles, and therefore, it produced less "impact" in terms of terminal ballistics than Red too.

As you mentioned, perhaps Black has better relative performance at shorter draws, but my 32-1/2" draw isn't all that long either (though it's about the maximum for Trumark tubes, I think). Most people get 29-30 inches just drawing to the side of their mouth, even. Break-in is something I never considered. I doubt the energy stored by the rubber improves with age but I can believe it might be possible for the rubber retraction speed to improve. The Black's I tested has a strong pull (though I did not measure it) so it is obviously slow and perhaps that will improve. I would not be surprised if both Black and Yellow last longer than Red, because Red is tapered.

I also have some 2 and 4 oz. fishing weights that I used for shooting over tree limbs (over 50' sometimes) to pull a haul line and survival saw for limb pruning from the ground. Maybe Black would really shine with the 4 oz (1750 grain) monster weight! I originally got it for this purpose, but the Red bands shot 4 oz fishing weights to 50' height and I never needed to use the Black. 2 oz weights travel even higher, but getting the weight to pull the leader against the friction of the limb can be challenging sometimes. Ahh-the fun of slingshot arboriculture!


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## wll

calinb said:


> i also use the trumark reds . the black ones have their purpose, yes they are harder to pull, they seem to last a long time, and once they break in, watch out ! imo- the blacks are more for people with short draws and want impact over speed. they are great for hunting small game with.
> 
> I'm not sure what you mean by impact (momentum, kinetic energy...?) But yes--that's what I thought Black was for too. When these parameters increase with higher mass projectiles it is at the expense of speed. That's why I tried the 54 cal. lead ball. There are not many people regularly shooting ammo heavier than that! Even so, Black still measured slower than the Red with the same heavy lead projectiles, and therefore, it produced less "impact" in terms of terminal ballistics than Red too.
> 
> As you mentioned, perhaps Black has better relative performance at shorter draws, but my 32-1/2" draw isn't all that long either (though it's about the maximum for Trumark tubes, I think). Most people get 29-30 inches just drawing to the side of their mouth, even. Break-in is something I never considered. I doubt the energy stored by the rubber improves with age but I can believe it might be possible for the rubber retraction speed to improve. The Black's I tested has a strong pull (though I did not measure it) so it is obviously slow and perhaps that will improve. I would not be surprised if both Black and Yellow last longer than Red, because Red is tapered.
> 
> I also have some 2 and 4 oz. fishing weights that I used for shooting over tree limbs (over 50' sometimes) to pull a haul line and survival saw for limb pruning from the ground. Maybe Black would really shine with the 4 oz (1750 grain) monster weight! I originally got it for this purpose, but the Red bands shot 4 oz fishing weights to 50' height and I never needed to use the Black. 2 oz weights travel even higher, but getting the weight to pull the leader against the friction of the limb can be challenging sometimes. Ahh-the fun of slingshot arboriculture!


Even though I shoot some heavy ammo,314gr, a 4oz weight may cause what is called a RTS (return to sender) very, very dangerous. Seems to happen with very heavy ammo and a fast power set that does not have the force to push that heavy weight fast enough.

There may be videos on this forum, or go to YouTube and type watermelon and slingshot and see a very graphic example of what I'm talking about.

wll


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## calinb

wll said:


> Even though I shoot some heavy ammo,314gr, a 4oz weight may cause what is called a RTS (return to sender) very, very dangerous. Seems to happen with very heavy ammo and a fast power set that does not have the force to push that heavy weight fast enough.
> 
> There may be videos on this forum, or go to YouTube and type watermelon and slingshot and see a very graphic example of what I'm talking about.
> 
> wll


Maybe I was just lucky (I've taken over 100 of these 2oz and 4oz weight shots with a cheap Wally World Daisy and a Trumark) and never had anything bad happen. The worst thing that happened is my very light haul line (200 paracord or 80 lbs test fishing line) often became fouled during its feed-out and took forever to untangle!

Maybe the dynamics change when a projectile is attached to a line (though intuitively one tends to think that a line, even loosely lain on the ground, would exacerbate the likelihood of RTS), or maybe the dynamics become more favorable with extremely massive projectiles (and I'm still talking far short of watermelon mass here). Due to dynamics and even some static phenomena, mechanical models often do not scale. Differences in dynamics between a test bed and an actually mechanical object can work for you or against you, but it's why the Comet crashed and the Tacoma Narrows bridge fell. What works in a scale model didn't work in real life--at least in the 40s and 50s before the empirical "fudge factors" became known!

I would never recommend that others do what I've done, but it sure worked better for me than trying to fling a weight over high branches by hand, which is impossible above about 20 or 30 feet and I can never throw as accurately as I can shoot! Slingshots saved me thousands of dollars that I would've spent on a real arborist to clear a great view!

I'll try to find some high speed camera footage of RTS with hand held slingshots. Without video, it didn't happen  (or at least maybe not the way people think it happens).


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## Henry the Hermit

This proves, once again, what many of us have been saying for years. Heavier pull does not necessarily mean more power.


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## gonene1

I have Barnett red bands and they where very hard to pull.

My new Chinese slingshot came with thin tubes that even though thin where very hard to pull also. (I think these where 2050 tubes, it also came with 3060 tubes but whey where so hard to pull that I did not even used them once.)

I ordered from dankung.com 10m of 1745 tubes which are thinner , they arrived two weeks later , and i found out that they are hard to pull as well.

In his videos Bill use a single tube per side with only the end of them looped to allow it to be attached to the slingshot.

But i did not order a one hole per side pouches only two holes per side , so i can't use this method at the moment.

I am thinking of buying a pocket predator slingshot , so i searched about it , how you connect tubes on it.

I found this video : 




It looks like the forks where designed to be used with thinner Chinese tubes, which are looped or half looped or looped just enough at the end to allow proper attachment.

How did you connect the fat trumark tubes to it?

It looks like the tube should be tied in a loop at the end of it, and wrapped all the way around the fork if you want to use the middle notch for aiming like a regular tube.

Did you manage this with the trumark?

Bill hays says the Chinese tubes are snappier.

I ordered some even thinner dankung tubes 1843 and 2040 , because the 1745 where too hard to pull for me.

for a 3/8 steel i think you don't need anything too heavy. something lite and easy to pull should be better.


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## Henry the Hermit

Unless yo are shooting ammo heavier than .44 lead, looped 2040 works at least as well as looped 1842 or 1745, with lower pull weight.


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## M.J

Henry in Panama said:


> Unless yo are shooting ammo heavier than .44 lead, looped 2040 works at least as well as looped 1842 or 1745, with lower pull weight.


:werd:


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## calinb

There are many ways to attach the tubes. I attached the single Trumark tubes to my Rambone by jamming an airsoft BB into the end of the tube. This is my TTF configuration. (I shoot it just like it's shown with the tubes coming straight back.) The screws heads of my two-piece 3D printed nylon Rambone face forward.



















It would work for my PocketPredator with holes in it too but I also have a PocketPredator side shooter with the double stud Titanium attachment system. This is the very one (GPO3) from Bill's gallery:

http://www.pocketpredator.com/gallery/x194.jpg

I just clamp the tube under the plates (plates facing forward and tubes wrapping rearward outside the forks--just like bands). They are very strong. I didn't cut any slits in my 3D printed Rambone so I used a length of string to pull the tubing through the hole by tying two half hitches in the string right at the end of the tube and lubricating the string, tube, and inside of the SS hole with rubbing alcohol first. After getting the tube to pass through the hole, it can then be pulled back and forth (being careful to not pull it back out) to rotate it to the correct position and length. Then jam the BB into the end and block the end of the tube, in case it "pea-shoots" loose. With pressure on the BB, you can stretch the tube into a locked position. After the rubbing alcohol dries, it's very secure. I've shot it both OTT and TTF using the Trumark tubes (reversing the direction of the tubes) with the Rambone and it works both ways. No fork hits but I'm confident the the nylon material I used to print it could take a fork hit!

I plan to try "pseudo-taper" 1745 tubes when they arrive from Dankung and shoot 44 cal. lead with them. (I'd prefer to refer to all these "taper" variations and concoctions as "progressive rate" or "dual rate," because those terms are well-known and descriptive when talking about springs.) I'll just pull the tubing through the hole before attaching it to a pouch and tie an overhand knot in the doubled tube to terminate the doubled section (an overhand knot will not slip). After attaching the tubes to the SS, I'll tie them to the pouch. With this setup, you could terminate the single tube to the single hole in the pouch. The longer the doubled section, the stronger the pull. You

Attach two tube ends to the pouch as shown in the video here at 30:40:

http://slingshotforum.com/topic/41275-slingshot-knowledge-101/

Also, Bill Hays covers more on tube attachment and the Titanium attachment system at 41:42. I recommend just watching the entire video. It's the most comprehensive SS instructional video ever made!


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## gonene1

I did not try a pseudo-taper because i don't have the right pouch for it.

the pouch i have bought have two holes on each side, and i don't think that you can use pseudo-taper with them.

they look like this.










anyway, I'll either make DIY pouch from some leather scraps or just wait for the 2040 bands to arrive. (I'll probably do both)

since the double strands 1745 where too heavy for me, i cut them way too long , so now it's easier to reach my anchor point but i get a lot of slack and less speed.

I think that a much shorter 2040 (large elongation factor) will be easier to pull then a longer 1745, and snap back faster.(for a 3/8 ball)

I'll try different setups and see what works best for me.

I think I will buy the seal sniper polymer , i am not sure what size of the three sized to get. (i hope that Bill Hays will help me with that)

I watched the video several times i did learn a lot, but the video does not show how to use the fork tips that is on the seal sniper, so i did not knew you can attach a tube to it lin the same method that you connect a flat band.

and another thing. your 3D printed slingshots looks amazing !!!


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## calinb

gonene1 said:


> I did not try a pseudo-taper because i don't have the right pouch for it.


Actually, your pouch brings up an interesting experiment to try. Just put the the pseudo-taper tubes on backwards (doubled end on the pouch and single end on the SS. You'll lose the benefit of having the reduced mass on the pouch end, but I suspect the "dual spring rate" nature of this setup is what provides most of the benefit. Someday I'll try the same tubes both ways and Chrony them to see how much difference the reduced mass factor makes. I'll wager that there won't be much difference in speed, because the extra energy required to move the extra mass of the doubled section of tube is small, compared to the energy required to move the projectile, pouch, and remainder of the tubing.

Thanks for the positive feedback on my 3D printed SSs! I have several other photos in the gallery, including different versions of Bill Hays' excellent Boy Scout design. Lacking dies to cut my own leather pouches, I 3D printed a nylon pouch template. It's the next best thing to dies, because it allows me to locate the holes perfectly using Harbor Freight punches

http://www.harborfreight.com/9-piece-hollow-punch-set-3838.html

and draw lines on the leather in pencil to mark where to trim the perimeter with high quality TiN coated Fiskars scissors. I think the lines and scissors work better than a knife or razor blade for cutting the perimeter but using the template to guide a blade works too. It's a very convenient and accurate method. I'll post photos or make a video someday.

I have a poly Seal Sniper too. Great SS! Just measure your hand from middle finger top to wrist crease and Bill can tell you which size to order. You can also order it with the single thumbscrew per side Titanium plate tie-less system for another 10 bucks. I really like the all metal plates and hardware and the single thumbscrew version for the Seal Sniper, which works great with tubes too, I'm sure.


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## gonene1

calinb said:


> gonene1 said:
> 
> 
> 
> I did not try a pseudo-taper because i don't have the right pouch for it.
> 
> 
> 
> Actually, your pouch brings up an interesting experiment to try. Just put the the pseudo-taper tubes on backwards (doubled end on the pouch and single end on the SS. You'll lose the benefit of having the reduced mass on the pouch end, but I suspect the "dual spring rate" nature of this setup is what provides most of the benefit. Someday I'll try the same tubes both ways and Chrony them to see how much difference the reduced mass factor makes. I'll wager that there won't be much difference in speed, because the extra energy required to move the extra mass of the doubled section of tube is small, compared to the energy required to move the projectile, pouch, and remainder of the tubing.
> 
> Thanks for the positive feedback on my 3D printed SSs! I have several other photos in the gallery, including different versions of Bill Hays' excellent Boy Scout design. Lacking dies to cut my own leather pouches, I 3D printed a nylon pouch template. It's the next best thing to dies, because it allows me to locate the holes perfectly using Harbor Freight punches
> 
> http://www.harborfreight.com/9-piece-hollow-punch-set-3838.html
> 
> and draw lines on the leather in pencil to mark where to trim the perimeter with high quality TiN coated Fiskars scissors. I think the lines and scissors work better than a knife or razor blade for cutting the perimeter but using the template to guide a blade works too. It's a very convenient and accurate method. I'll post photos or make a video someday.
> 
> I have a poly Seal Sniper too. Great SS! Just measure your hand from middle finger top to wrist crease and Bill can tell you which size to order. You can also order it with the single thumbscrew per side Titanium plate tie-less system for another 10 bucks. I really like the all metal plates and hardware and the single thumbscrew version for the Seal Sniper, which works great with tubes too, I'm sure.
Click to expand...

Well i took your advice about the backwards pseudo-taper , but only half way.

I made a pseudo-taper 1745 tube (not half looped, but one that will fit a ball in tube attachment method and all connections where made with cuffs)

I now had to come up with a solution to attaching it to the two hole pouch , so i attached to the pouch a tiny 2040 looped band only 1 inch long.

it worked really well, but since i did not calculate the additional 1inch 2040 tube in the total length , what i got was a bit too long tube band for my draw length , and this cost in speed.

(I can't measure the speed but i feel that it was easier to pull then the regular double 1745 and gave about the same speed\force , if i cut it a bit sorter it would be faster yet still easier to pull)

here is a photo of the band


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## calinb

gonene1 said:


> it worked really well, but since i did not calculate the additional 1inch 2040 tube in the total length , what i got was a bit too long tube band for my draw length , and this cost in speed.


Sounds good!

The 2040 "adapters" added 1" to your inactive length but they should perform roughly like having an extra inch of the 1745, based on the relative cross sectional area of the the two types of tubing:

1745: (45-17)^2 = 784

2040: (40-20)^2 * 2 = 800

800 ~= 784! 

As you now realize, you can simply reduce the length of the single 1745 section by 1" (the length of the 2040 adapters) and your tubes will perform just about the same as the same length 1745-only tubes would perform when tied to a single band attachment hole pouch. That's what I predict anyway.

I chrony'ed the 2040 looped tubes on my new Torque yesterday. I was somewhat amazed at the speed of 2040 when doubled!

About 500% elongation, pulled ~30" to my cheek on a hot, almost 90F day:

3/8" steel: 185 fps average

1/2" steel: 152 fps average

So 2040 loops produce roughly the same speed as Trumark black (179 fps / 146 fps) or red (185 fps / 153 fps) when shooting 3/8" / 1/2" steel with what I perceived to be a lighter pull than even red! (And the black vs. red numbers above are correct; I DID measure Trumark red to be slightly faster than black, despite its lighter pull than black!) I say they are "roughly" the same speed with the 3/8" and 1/2" ammo, because the weather on the day I chrony'ed the Trumark bands was considerably cooler than yesterday's 2040 testing.

Also, I'm not exactly the fastest shot in the west (leaving time for the bands to cool) but I was trying for speed.

If you eliminate the extra length and increase your elongation factor, your dual rate-progressive (I like this term better than pseudo-taper) 1745 bands should be even better the above performance!


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## calinb

Oops--the 146 fps and 153 fps were for 53 cal. lead for black and red respectively, as I reported earlier in this thread, and not for 1/2 steel. The 3/8" steel was just about dead even between red and the 2040 looped tubes and just slightly slower with the black so the Trumark tubes are going to do better than looped 2040 tubes above 3/8" steel ammo weights.


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## NaturalFork

Of course. The black tubes are pretty useless unless you are shooting arrows.


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## wll

Pretty interesting when you start running your set ups over the chrony and get the facts not the hype. it is important info because it is what YOU get for YOUR set up and YOUR style of shooting.

wll


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## calinb

wll said:


> Pretty interesting when you start running your set ups over the chrony and get the facts not the hype. it is important info because it is what YOU get for YOUR set up and YOUR style of shooting.
> 
> wll


Yeah--that's a good point, wll. For example, I've learned that even a small change in my anchor point changes the band loading enough to significantly change the chrony reading. I also discovered that the black bands were so much harder to pull, that I really had to concentrate on pulling them as far as the others to get a fair comparison. Even subconsciously "whimping out" a little with them caused them to produce low and unrepresentative chrony readings.


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## poekoelan

Very important point made by wll. Others speeds with certain bands and ammo are only guidlines. Personally I find that for a given band and ammo combination, most people seem to get more speed than me. Draw length, band length, shooting style and temperature are key factors to consider. The only person who seems to get slower speeds than me is Northerner.


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## calinb

poekoelan said:


> Very important point made by wll. Others speeds with certain bands and ammo are only guidlines. Personally I find that for a given band and ammo combination, most people seem to get more speed than me. Draw length, band length, shooting style and temperature are key factors to consider. The only person who seems to get slower speeds than me is Northerner.


And then there's the issue of how you run your chronograph. It's easy to make a folding Chrony read low (just shoot at a slight angle) but it can also read high in certain lighting conditions (where the first sensor trips on the trailing edge of the projectile but the second sensor trips on the leading edge). I have seen this happen consistently during a string of fire. When it happens, it's time to change the angle of the Chrony relative to the light source and/or move/remove/change the diffuser screens.


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