# Chrono testing - Face anchor vs. half butterfly vs. full butterfly (6mm & 9.5mm)



## GnuUser (Aug 31, 2019)

I did some chronograph testing today. I keep thinking that shooting butterfly will result in much higher velocities than a face anchor, but that turns out not to be the case for smaller ammo. I just don't find much benefit from using butterfly with smaller ammo, and would be interested to know if my results match up with what others experience.

I'm a target shooter who shoots mostly 6mm ammo, with the occasional dabble in 9.5mm when I want more impact (which is rarely). I was expecting that my speeds would increase substantially with a longer draw length, but that didn't really turn out to be the case for the ammo I shoot.

For 6mm ammo, there's little to no benefit from shooting full butterfly. I get a slight speed increase going from a 68cm draw to a 145cm draw, but not much, and certainly not enough to offset the risk of getting slapped in the face (which does happen from time to time). I can get velocities just as high by using wider bands, and even at a better velocity-to-draw force ratio.

For 9.5mm ammo, using the same bands, there's a more consistent speed increase going from a 68cm draw to a 145cm draw. But, again, I can get the same speed increase at the shorter draw by using wider bands, and still at a better velocity to draw force ratio.

For much heavier ammo, maybe there's a benefit, but for small ammo like I shoot, I can't see any reason to shoot half or full butterfly. This is about the third time I've looked into this. Every time I keep thinking the butterfly shooting will win out, but I always go back to a face anchor because butterfly doesn't add any benefit for me. I'm not knocking butterfly at all. I'm just surprised that it doesn't have the benefits I hear about for the small ammo I shoot.


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## JASling (Feb 4, 2019)

Good deal 

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## Island made (Aug 14, 2019)

Nowadays with modern elastic short draw is definitely more efficient then it was 10 years ago. With gum rubber and even tbg there is a substantial difference in speed. I still love butterfly because I feel all boxed up using short draw. 
Thanks for sharing your results.


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## GnuUser (Aug 31, 2019)

Island made said:


> Nowadays with modern elastic short draw is definitely more efficient then it was 10 years ago. With gum rubber and even tbg there is a substantial difference in speed. I still love butterfly because I feel all boxed up using short draw.
> Thanks for sharing your results.


I hadn't considered improvements in elastics. That makes a lot of sense, and answers a lot of my questions on the issue. If newer elastics are more efficient at transferring power, then there won't be as much of a difference in power because of length. I've only been shooting for about 2 years, and so have only ever used newer elastics (if you ignore the horrendous tubes on the wrist rockets I shot as a kid and first bought when I got into slingshots as an adult).

I have tried chains of office rubber bands, and absolutely hated them. I couldn't get much above 55m/s (about 180ft/s), and I much prefer the crispness of shooting around 75m/s (about 250ft/s). That's the sweet spot for me. Much higher is not worth the effort, and much lower feels like a lob.


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## GnuUser (Aug 31, 2019)

Also, for what it's worth, I'm using SimpleShot's 0.5mm black latex. This stuff is awesome. I've tried their natural latex and some pre-made Chinese bands, both of which were good, but SimpleShot's new black latex is the best, and it doesn't lose much power at low temps.


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## Island made (Aug 14, 2019)

As a kid I shot chains all the time! They’re were about the same speed as the big crappy tubes, but we’re way more accurate. And a kid can make them themselves from office rubber! Lol. A lot of the old setups didn’t go faster than 180 FPS, but they would hold the speed with heavy ammo, that’s why years ago everyone shot 1/2” steel and big lead. I have taken lots of grouse and rabbits with chained bands and big ammo. Now I use modern elastic, 3/8” steel and a 65” draw About 350 Pfs.


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## High Desert Flipper (Aug 29, 2020)

I have played around with different things related to this and your result makes sense. Overall, butterfly allows much faster velocities. Although there are cases where the advantage of the longer powerstroke disappears, and it looks like you have found one. Specifically, all elastic has a maximum retraction rate- the top speed it will contract at. This top speed is the top speed, and drawing twice as far won't increase it. So when the ammo is light enough for the bands to get close to their maximum retraction speed, the advantage of longer draws disappears. With heavier ammo the short draws don't get close to maximum retraction rate, the longer draws don't either but the extended power stroke lets them get closer. But excellent test and great result, thanks for sharing the info! Especially because some may be disappointed to not get the expected result and wonder why.


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## GnuUser (Aug 31, 2019)

Island made said:


> Now I use modern elastic, 3/8” steel and a 65” draw About 350 Pfs.


Holy cow. I bet that packs a punch. I'm going to have to try that, just for kicks. Might break the backstop of my catchbox, though.


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## GnuUser (Aug 31, 2019)

High Desert Flipper said:


> Especially because some may be disappointed to not get the expected result and wonder why.


Thanks for the additional info. Yes, I have been kind of disappointed and wondering why I wasn't getting a difference in speed and power. But, I only shoot light ammo. It doesn't take much force to accelerate a 1g ball up to speed, I guess.


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## High Desert Flipper (Aug 29, 2020)

And like you said, you can always get the same velocity increase from short draw by using wider bands. Another way to think of it, with butterfly you can get the same velocity with thinner bands with much less draw weight. My experience is I can cut the draw weight in half and get the same or better velocity with full butterfly- depending on ammo size of course. And for large ammo, like 1/2", I have a hard time pulling any short draw band set that will get it over 200 fps- bands that do that pull over 20 lbs for me at 29" draw. I can sorta get them back but have a hard time being accurate. But full butterfly, I can do get 1/2" over 200 fps and a bit more with bands that pull ~12 lbs. And with 3/8" ammo, even bands pulling under 10 lbs get it over 300 fps at my ~55" butterfly draw.

Now the only challenge left for me is to get my butterfly shooting to hit anything. I play with it a bit here and there. I have gotten comfortable shooting it enough to put some over the chrony and be impressed with what it does. And am now at the point where 8 or 9 out of every 10 shots hit the catch box. Some days 1 or 2 even hit the can.


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## GnuUser (Aug 31, 2019)

High Desert Flipper said:


> And for large ammo, like 1/2", I have a hard time pulling any short draw band set that will get it over 200 fps- bands that do that pull over 20 lbs for me at 29" draw. I can sorta get them back but have a hard time being accurate. But full butterfly, I can do get 1/2" over 200 fps and a bit more with bands that pull ~12 lbs. And with 3/8" ammo, even bands pulling under 10 lbs get it over 300 fps at my ~55" butterfly draw.


All very good points, thanks. I've never shot heavy ammo, and have never seriously tried to max out speed (over about 90m/s (300 f/s), so I guess I've never been in the zone where shooting butterfly made much difference. However, holding a 20lb draw on ammo held between your forefinger and thumb would be difficult, so having half the draw weight for the same ammo speed would be a major advantage.



High Desert Flipper said:


> Now the only challenge left for me is to get my butterfly shooting to hit anything.


 With the light ammo and light draw weights, I'm pretty accurate with it, but the long, dangly bands are harder to load and I don't like the bands and ammo whipping past the side of my face at speeds fast enough to cause injury. I haven't hurt myself, yet, but have had the pouch snap my cheek from time to time.


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## GnuUser (Aug 31, 2019)

Island made said:


> Now I use modern elastic, 3/8” steel and a 65” draw About 350 Pfs.


By the way, what kind of bands are you using to do that? I may give it a try, just out of curiosity. I'm thinking something like 0.5mm with a 30mm to 10mm taper. Thoughts?


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## Island made (Aug 14, 2019)

GnuUser said:


> By the way, what kind of bands are you using to do that? I may give it a try, just out of curiosity. I'm thinking something like 0.5mm with a 30mm to 10mm taper. Thoughts?


Really any elastic, but my favourites are simpleshot black, and snipersling black and yellow. 
My cut is 3/4” to 3/8” 12” active with .6 elastic for a 65” draw. Metric would be 19mm to 9.5mm


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## pinguinu01 (Mar 15, 2019)

Are you using the same band width for short, half butterfly and full butterfly?

For longer draw you need less elastic than for short draws.
Too much elastic will just be more weight and not contribute to velocity increases.


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## High Desert Flipper (Aug 29, 2020)

pinguinu01 said:


> Are you using the same band width for short, half butterfly and full butterfly?
> 
> For longer draw you need less elastic than for short draws.
> Too much elastic will just be more weight and not contribute to velocity increases.



I believe the general rule of thumb is the longer the draw the narrower the band. And in the end the volume of latex remains about the same, and it is just whether that amount of latex is distributed short and wide or long and narrow.


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## Reed Lukens (Aug 16, 2020)

Your full butterfly gives you a longer band to bring your ammo up to the full speed that it is capable with that particular band. If your shooting 6mm ammo, then a 1/2" band should be more then enough with a .5 thickness. You also have to figure in the correct elongation ratio for the band that you're using. For the Sobong that I'm using today, it has a 500% max stretch ratio, where with the Precise that was using last week, it has a 750% stretch ratio. Which one will react the fastest, is the result that I'm looking for today on mine 😀 

I think that using a wider band with a short draw is going to take a lot more strength to pull back then a narrower full butterfly draw to get the same result. At least, that's my thinking right now. I love shooting full butterfly because I'm standing the bands directly on top of each other, just under my eye, for aiming. I can look at the bands and tilt my fingers a bit if my bands aren't perfectly straight. Then I use that line of sight to put my shot on target. 
Personally, for 6mm ammo, I think that the .5 simpleshot could be cut to a 1/2" max width for maximum speed, but it may be a whole lot less. I started out with a 1" to 3/4" taper for 1/4" ammo that puts me over 400fps and that was still way to much band for that, but I usually shoot 7/16" up to 5/8 marbles when I'm not speed testing, which it is perfect for. I'm using .4 to .45 latex of all brands on my slings now just because I'm achieving better speeds with a much lighter pull. I will always be searching for that perfect match band to ammo ratio because that's a big part of the fun for me. 

Valery pointed out to me on another thread that making sure that the .5 is actually .5 with a micrometer makes a big difference also. It looks like the manufacturers can make a certain thickness and then mark it differently in different boxes. The Sobong was right on the money at .4mm where none of the other brands were anywhere near the same tolerances. So the micrometer has become an essential tool in my slingshot kit. 
I guess the bottom line is, if your achieving the same speeds with different draw lengths, what are the different tapers that you're using to achieve the same speeds? You may be using a lot more latex then is needed. I'm using a 3/8" straight cut for standard 6mm clay plinking. 
Thanks for all of the info above, there's lot's of great ideas in this thread 😀


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## GnuUser (Aug 31, 2019)

Sorry for the delayed response to the last few posts. I'm not getting email updates for this thread, and I don't know how to fix that.

To answer some of the questions, I tried to make the testing as consistent as possible. All tests (except the 20mm) were done with the same exact set of bands on the same Axiom Occularis slingshot (so that I could easily change the band lengths). The bands were SimpleShot 0.5mm black, and were straight-cut to 10mm. The draw ratio for all tests was set to 500%.

The 20mm, short draw comparison was done with a slightly tapered (20mm to 17mm) bandset that I already had on another slingshot. The draw ratio was also set to 500%. I was too lazy to cut another bandset or do any further butterfly testing with wider bands, so I didn't.

I'm guessing that if I tried wider, tapered bands (e.g., 20mm to 10mm), I'd get speeds close to those listed above (350fps for 3/8" ammo; 400fps for 1/4" ammo).

Thanks, all, for the fantastic information and advice!


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## europunk (5 mo ago)

Island made said:


> As a kid I shot chains all the time! They’re were about the same speed as the big crappy tubes, but we’re way more accurate. And a kid can make them themselves from office rubber! Lol. A lot of the old setups didn’t go faster than 180 FPS, but they would hold the speed with heavy ammo, that’s why years ago everyone shot 1/2” steel and big lead. I have taken lots of grouse and rabbits with chained bands and big ammo. Now I use modern elastic, 3/8” steel and a 65” draw About 350 Pfs.


Wow island, hats what I’m trying to shoot. I’m using black theraband (.38mm) tapered at 20mm-15mm with a 60” draw and shooting 3/8 steel can’t really get it moving right around 180 fps. How can I get 300+ with the 3/8”? Will .7mm work? Any recommended taper? Thanks again


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## Chicxulub (Jul 14, 2021)

take double or triple layers. that stuff is so thin. it takes some rubber to get the babies flying... 😁👍


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## zachpress1 (Jul 22, 2019)

GnuUser said:


> Sorry for the delayed response to the last few posts. I'm not getting email updates for this thread, and I don't know how to fix that.
> 
> To answer some of the questions, I tried to make the testing as consistent as possible. All tests (except the 20mm) were done with the same exact set of bands on the same Axiom Occularis slingshot (so that I could easily change the band lengths). The bands were SimpleShot 0.5mm black, and were straight-cut to 10mm. The draw ratio for all tests was set to 500%.
> 
> ...


Hey mate, old post I know but I have had a thought.

What if in your butterfly testing you used narrower straight cuts? So 10mm as your standard, and then 5mm or 7mm straights at same elongation when you test full butterfly.

I expect you would see a drop in draw weight, without a corresponding drop in velocity, thereby improving your draw weight:velocity ratio?

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