# Chrony Tests Explained



## Bill Hays (Aug 9, 2010)

I had several inquiries over the last couple of weeks and then 3 today alone asking about chronograph results... bands versus tubes, draw lengths and weights... hey thanks a lot Hawk and John, as if my day wasn't busy enough already!

So I made a quick video to show the difference.
Latex and Gold Thera Bands are faster than tubes. Tubes are capable of lasting much longer than flats. BOTH are capable of taking small game and target shooting to your heart's content.

Here's how they stack up when cut to accomodate the draw properly:
At a draw weight of 12 lbs. and a draw length of 44", gold theraband cut 1" X 9" straight at one band per side will propel a .44 cal (11mm) steel ball 260 fps.
At a draw weight of 20 lbs. and a draw length of 44", four 1745 black tubes will propel the .44 cal steel ball at 250 fps.
At a draw weight of 14 lbs. and a draw length of 44", two 1" - 3/4" taper X 9" long 0.04 latex bands will propel a .44 cal steel ball 296 fps.
At a draw weight of 20 lbs. and a draw length of 35", looped 1745 amber tubes propel the .44 steel ball 222 fps.

The most important thing to remember on either tubes or flatbands is to cut them to fit your draw length. Once you have the proper thickness and dimensions to propel your chosen ammo optimally you will get a LOT more satisfaction from either tubes or flats.


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## gamekeeper john (Apr 11, 2011)

thanks for the video bill


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## gamekeeper john (Apr 11, 2011)

bill what if you have 2 people of the same strength, one with short arms and one with long arms, they would require the same lb of draw but with different band lengths, so people with a longer draw would probaly get more power than people with a shorter? so this means everybody has a different lb and draw length, and most catapult companys supply there catapults with a standard band set, so there must be a lot of people out there who are shooting the wrong lb and draw length for them, its only my opinion and i might of got this wrong but i hope you can see were i'm comming from? thanks john


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## Bill Hays (Aug 9, 2010)

John,
Yep, I believe everybody pulls a little different, so chrony readings are only valid if you know the draw weight, draw length and weight of the ammo. 
Hawk's natural draw, your draw and my draw, for example, are all quite different.


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## philly (Jun 13, 2010)

Very interesting and informative Bill, thanks. Question, (you knew you were going to get this one) How does someone determine the proper band length for thier draw length. For instance, I am shooting 7/8x5/8 .030 latex by 7 1/4" fork to pouch tie with a draw of 31", chrony tests yesterday resulted in 175 to 185 FPS. I would like to see more speed and a flatter trajectory at 25 yards using 3/8 steel for target. Is there a formular to determine proper tied length to achieve a certain speed with a given band cut? Or is just trial and error? I am sure there are alot of guys on here that struggle with the same problem.
Philly


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## Peresh (May 3, 2010)

Philly, we are shooting the same latex, the chrony test yesterday revealed, I did 205-209. So I guess we are not using the same tapers. You also have a longer draw than me.


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## Bill Hays (Aug 9, 2010)

Philly,
I'd undo the pouch side and take out 1" of band, making them 6 1/4" fork to pouch... so that the bands will be stretching 5 times their relaxed length.
I'd think that you'd be close to optimal with a 1" tapered to 3/4" X 6" long (pouch to fork).... that should be perfect for 3/8" steel and should put it out there at around 210-220 fps.
If you want to go with heavier ammo, and it depends on how much heavier, either double up the bands or use thicker bands... Single side 1"X3/4" tapered 0.03 latex is perfect for 3/8" steel. Doubled up you can shoot .44 lead and .50 cal steel at 220 fps.


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## shooter452 (Nov 6, 2010)

Very informative video. It explains how and why people get such varying results. One more question for a very busy man. It appears the tubes in the video are tied? Any chance of a close up of that (assuming it is more than just looped thru)? Thanks! The reason I ask its wondering if you have a similar point of aim for flats and tubes?

One observation on your outstanding video. How would the results change with a fresh set of tubes?


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## M.J (Nov 1, 2010)

I wish I could draw back that far comfortably. My current draw of 34" is to the back of my jawbone and if I go any further I loose all accuracy.
My ideal setup would be a straight-cut Theraband that would deliver 3/8" at 220+ fps. I have 7/8" doubled TB Black on now and it does pretty well, draws easy enough and should last a long time, but I feel that it's less than ideal. My target shooter is set up with doubled Silver (off-brand equiv, actually) cut 22cm long tapered 22x11 mm and they are very speedy but blow out too soon. I'm going to keep experimenting until I find a good compromise between speed and longevity.
Thanks for the test and the video, Bill.


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## philly (Jun 13, 2010)

Bill Hays said:


> Philly,
> I'd undo the pouch side and take out 1" of band, making them 6 1/4" fork to pouch... so that the bands will be stretching 5 times their relaxed length.
> I'd think that you'd be close to optimal with a 1" tapered to 3/4" X 6" long (pouch to fork).... that should be perfect for 3/8" steel and should put it out there at around 210-220 fps.
> If you want to go with heavier ammo, and it depends on how much heavier, either double up the bands or use thicker bands... Single side 1"X3/4" tapered 0.03 latex is perfect for 3/8" steel. Doubled up you can shoot .44 lead and .50 cal steel at 220 fps.


Thanks Bill, I'll give it a try tomorrow.
Philly


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## slingshot_sniper (Feb 20, 2011)

Good stuff this










I think I got this right....so a good starting point for me would be 7" band length fork to pouch a draw at 35" should get me close to the speeds Bill gets (same band set)............Am'I close Bill?


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## hawk2009 (Dec 30, 2009)

Great video Bill, but the video I posted first off was very simple I had just bought a chrony and wanted to see what speed I was target shooting at the only reason I put Johns gamekeeper catapult on the video also is because it's the only one I have and it was their ,it never was a comparison between the two,I haven't watched the video again but i'm pretty sure I made that quite clear.but it seems some just dont listen just watch get on their high horse and then the topic gets distorted. I did this because when many chrony tests are done you cannot see the shooter but you can hear them straining struggling to pull the tubes or bands back and my personnal opinion is it's not a realistic shot so for my own curiosity and thats all I did it for was to get a more realistic figure, I know and fully understand draw length, mine are cut longer than my draw to prolong the life of the tubes and as you can see on my video's I get good power so i'm happy with this. I'm also fully aware that John's bands are to long for me but like most other shooters you dont tend to alter what you have received so you shoot with it just as they are and the results are as they are, if I picked up john's catapult to shoot a few shots I would not alter anything unless it was my everyday catapult so for my tubes to come out on top i'm not surprised as they are nearer to my draw length than the custom made flatband.But then through the ridiculous comments made by others a simple video got twisted out of all proportion. And no matter how many times I tried to explain it was not a comparison between tubes and flats they didn't listen so in anger and tiredness of working nights I posted another video as you can tell I was not at all pleased it seems some some on the forum are out to aggravate and cause trouble and I took the bait sorry you had to straighten this out Bill. I did try to myself.


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## JeffsTackleBox (Apr 10, 2011)

Nice done Bill. I guess I'm still at the stage where I shoot like a bow. My regular draw archery style is to the corner of my mouth about 31.5 or 32 inches depending on the stance. Accuracy wise I'm hitting those vicious soda cans pretty regular. So much so that they try and hide out in the recycle bin. Keep the good infomation coming. The more I see and read about this simple sport the more fun it becomes.


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## Gwilym (Dec 9, 2010)

Lol you should have known hawk no matter what you did it would turn out to be a comparisson especially as you posted a speed at max draw as well. Regardless bill you did a great job for anyone left wondering by john and hawks vids.


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## hawk2009 (Dec 30, 2009)

Gwilym said:


> Lol you should have known hawk no matter what you did it would turn out to be a comparisson especially as you posted a speed at max draw as well. Regardless bill you did a great job for anyone left wondering by john and hawks vids.


 I had to show the difference between how when pulling to the max differed from a normal draw to length shot thats why I only fired one shot. if it was a comparison between the two I would have to shorten the flats to my draw length and also shorten mine as they are also to long, but as you probably know I dont use flats I dont like them (personnal preference only) the reason i have not shortened them is because I was going to run a competition and put John's gamekeeper catapult up for grabs,I dont dislike it it's a great catapult extremely well made but I will never use it so thought I would pass it on to a forum member who would use it. But after all whats been said and ongoing at the moment I think I will put it in my draw to gather dust, no offence intended to you John. I won this in a competition I love competition as I have entered into Bills also and if I did win this quality slingshot from another great maker, I would have no doubt offered this up in a competition also but I would like to see it first ( note I put if I did win it) as the competition is far from over it would be wrong to assume .


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## Hit and run (May 14, 2011)

Great info, I've been searching for draw weights for TBG and 1745 and here it is,







thanks.

One question tho, how long are the tubes undrawn?


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## Dayhiker (Mar 13, 2010)

This is a great thread! Thanks Bill -- and everybody else who is contributing info.


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## philly (Jun 13, 2010)

philly said:


> Philly,
> I'd undo the pouch side and take out 1" of band, making them 6 1/4" fork to pouch... so that the bands will be stretching 5 times their relaxed length.
> I'd think that you'd be close to optimal with a 1" tapered to 3/4" X 6" long (pouch to fork).... that should be perfect for 3/8" steel and should put it out there at around 210-220 fps.
> If you want to go with heavier ammo, and it depends on how much heavier, either double up the bands or use thicker bands... Single side 1"X3/4" tapered 0.03 latex is perfect for 3/8" steel. Doubled up you can shoot .44 lead and .50 cal steel at 220 fps.


Thanks Bill, I'll give it a try tomorrow.
Philly
[/quote]

Bill, cut my bands to 6 1/4 inches at the pouch side as suggested, I don't have a chrony avaialble but can see a real improvement in trajectory at 25 yards. Thanks for the help. I will be trying my hand at cutting my own bands this weekend, and will try your recomendation on 1'x3/4'x6 in .030 latex.
Philly


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## Peresh (May 3, 2010)

Bill,
I tried the 6 inch short cut bands instead of 7 1/4" and the bands broke even faster. I got better speed but the wear on bands at max is so quick of .30 latex. Not sure if compensating longetivity is that crucial in my case atleast.
Peresh.


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## philly (Jun 13, 2010)

peresh said:


> Bill,
> I tried the 6 inch short cut bands instead of 7 1/4" and the bands broke even faster. I got better speed but the wear on bands at max is so quick of .30 latex. Not sure if compensating longetivity is that crucial in my case atleast.
> Peresh.

















Mine had just started to tear at 7 1/4" so I managed to get double use out of them. I will try and keep count but they already had about 200 shots on them before I shortened them. Gansta has some real possibilities but there is alot more to think about than in instinctive( I sound like Yogi)







. Onward and upward.
Philly


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