Roller gun bands

[Diver278]

Hi I would like to know how you guys measure your band length. Or what your formula is. Thanks

[Diver278]

Wow 898 views and no reply. Can’t believe everyone has spearguns with no rubber on them.

[jersymudsniper]

I am no pro and dont do the formula stuff for any type of gun. Not saying you shouldnt. Or it wouldnt work better. But i dont. My rollers i just set up with about 4 or 5 inches of pretension. My band guns i grab the band pull on it and say…… .mmmm thats about right.

[Fox55]

so this is just me and well I'm a spear o soooo some people say I'm some what Psychotic but i prefer eccentric masochist!!!

Anyway this is what i do. on top, measure from the closest anchor to the trigger mech on your spear to the center of the roller, then on the bottom measure from the roller to your anchor, closest anchor to the trigger mech then add them together then take that number and divide by your band stretch %. so say 300% that would be 3.0 and 350% would be 3.5 me i go with 325% so 3.25..
so my wood and carbon fiber roller is 36 on top and 16 on the bottom = 52 then divide by 3.25=16 OK now you have to add 1'' for your constrictor knots so you end up with 17''.
i believe most manufacturers go with 250% but remember I'm a eccentric masochist!! and its your life! if you have a pipe gun call the manufacturers. but start out safe you can cut the bands shorter but you cant add to them. To much power on a shaft will do all kinds of bad things. so i keep it simple

[Diver278]

Thanks fox55 for the feed back

[Fox55]

No problem any other questions just give a shout

[Mikel_24]

Originally Posted by Fox55

...my wood and carbon fiber roller is 36 on top and 16 on the bottom = 52 then divide by 3.25=16 OK now you have to add 1'' for your constrictor knots so you end up with 17''.

Mmmm.... Fox, with these numbers... seems like you have little to no pretension at all in your bands, is that right?

My understanding is that the goal of a roller is to be able to push the shaft during the whole time/lengtht the shaft is on the gun... with no pretension (or very little) you don't get to acomplish this goal, I guess.

Why is the distance between the center of the rollers and the furthest anchor (closest to the trigger) only 16"?

Best regards,

Mikel

[Fox55]

First and foremost pretension is not an absolute requirement some people like it some people don't and my gun does have pre tension. the measurement from the center of the rollers to my rear anchor on the bottom is 16 in my wishbones on the back of my rubbers I cut and tie at one inch my anchor at the back is three quarters of an inch wide then you have the measurement around your rollers from the bottom of the gun up to your top rail 2 and a quarter inches as I said I was giving simple measurements not technical if you want technical you need to talk to Tim man and use his mathematical chart good luck it's a little confusing. But again not Everyone likes a lot of pretension my gun has roughly 4 to 10 lb of pretension depending on what style of bands I use I just got back from the lake this weekend and my chest is currently black and blue more pretension more black and blue

[Fox55]

You can also change your band stretch power percentage and this will give you a shorter band which that'll give you more pretension. If you look at my gun above you'll notice I have three notches. I measure to my Center notch and put my power at 325 percent now if I go to my front notch I drop down to 300% this way I can hunt holes with the same gun or I go all the way to my back notch and now I have 350% which I'm currently shooting accurately at 25 ft but loading at this means lots and lots of black and blue

[Mikel_24]

Originally Posted by Fox55

First and foremost pretension is not an absolute requirement some people like it some people don't and my gun does have pre tension. the measurement from the center of the rollers to my rear anchor on the bottom is 16 in my wishbones on the back of my rubbers I cut and tie at one inch my anchor at the back is three quarters of an inch wide then you have the measurement around your rollers from the bottom of the gun up to your top rail 2 and a quarter inches as I said I was giving simple measurements not technical if you want technical you need to talk to Tim man and use his mathematical chart good luck it's a little confusing. But again not Everyone likes a lot of pretension my gun has roughly 4 to 10 lb of pretension depending on what style of bands I use I just got back from the lake this weekend and my chest is currently black and blue more pretension more black and blue

Fully understood Fox55! I didn't take into consideration the diameter of the rollers or the thickness of the stock. My bad.

And yes, pretension is not a requirement.

Best regards,

Mikel

[Fox55]

It's all good. its all what your are comfortable with