16 replies to this topic

[pop shot]

Double TBG 3/4x 4", to double 2040 @ 4". Not too hard to make and they shoot real hot. I'll do a bean can test tomorrow. No chrony yet.

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[Hrawk]

Very interesting!

Looking forward to the can test!

[Vekta]

This, I want to see. I did the same sort of thing with scrap Theraband silver. I half expected it to come undone and slap me in the forehead. It didn't.

Could you maybe perhaps shoot some 1/2" steel with it to? Peez? Pretty peez?

[e~shot]

Good setup, waiting for the results

[pop shot]

tested with 1/2" lead, not too fast but still penetrated, i think i need to trim the tubes a bit. the steel shot really fast, popped a nice hole clean into the side. i'll retest with lead after i cut the tubes down. Feral hybrid test 1

[M_J]

I can't tell exactally how you have those tied but why not use two loops instead if tying them with string? If there's no hard-tie point the sets will almost certainly last longer..
I like the combining of materials, here's hoping for continued devolopment.

[NaturalFork]

Fera Taper?

[M_J]

NaturalFork, on 07 February 2012 - 12:35 PM, said:

Fera Taper?

There is Fera involved!

[pgandy]

Thanks for sharing.

[pop shot]

M_J, on 07 February 2012 - 06:19 AM, said:

I can't tell exactally how you have those tied but why not use two loops instead if tying them with string? If there's no hard-tie point the sets will almost certainly last longer..
I like the combining of materials, here's hoping for continued devolopment.

i took the looped end of the dTBG and wrapped it around the two tube ends. i don't think tube loop vs. tape loop would last as long. too much sawing friction when stretching. also super messy. i basically just rolled the tubes with TBG and clamped with a haemostat and tied with a constrictor. all i had for tubes is 2040. 1745 on order. i'm gonna shorten the tube section so that the tubes nearly max out and subsequently pull the TBG to near max as well. i think they will do well with heavy ammo when tuned up. these were way too long.

[timdix]

This opens up a raft of new band permutations...well done popshot.
I agree with MJ on using the loop at the pouch end instead of a tie.Also use rubber strips and don't tie too tight. My 1745 tapered set ups get around 300 shots even when bottomed out.
When I get back from holiday I'll chrony a single 1745 with a loop of around 2-2.5cm of TBG at the pouch,aiming for a 2:1 draw weight.
The 1745 set up is extremely punchy so if this even faster then we could be on to something.
I use a total length of 10.5 inches drawn to the max. Remember popshot,by shortening the bands and draw length one does get a significant velocity drop off.

Edited by timdix, 07 February 2012 - 08:02 PM.

[pop shot]

Gonna disagree on the loop to loop connection. Mock it up and pull it- the TBG loop does this funky jelly roll move, not too conducive to longevity. And it's just a mess to sort every time you load the pouch.

[pop shot]

Wait- I just realized, are you guys talking about the pouch tie? I'm talking about the TBG/2040 junction

[timdix]

The loop should attach to the tube at junction. Don't like that funky jelly thing though.It doesn't happen with the 1745 tapered set up. Try using a single 1745 instead of the 2040.Tying off with a single hopefully will keep it more stable.

[pop shot]

Stability is not the problem. The length needs adjustment to max out the TBG and 2040 at the same time so that they're pulling evenly.

[M_J]

That's cool, man, do your thing.
I was initally talking about two loops coming together in the middle but I can see how that would get all bound up after the shot. Timidix does have a good point about the pouch attachment though. I make my fixed sets that way and it really cuts down on the bulk at the pouch and they're easier to make. Got the idea from Hrawk:


Also in my experience Chinese tubes work best when stretched to 500-550%. If you pull them until they bottom out and won't pull anymore they lose alot of power.

[pop shot]

Ok, I understand. For a sec we were talking different things. I did the pouch attachment for adjustability, as it was the first attempt, it's also kinda tough getting the length dead nuts without a specific jig. I'm just gonna go with 550% for both TBG and 2040. Thanks for the input guys, make a set and try em out