quick question for rubber size

  • yesterday I tried my heavy wood short gun 95 cm with 7.5 mm spear 130 cm with 33 cm overhang , rubber : 14.5 small ID 360% ,14 small ID 380% , shooting in short range perfect little high but at end of 2 wrap mono it seem it shoot low ,I am confused what I should do ?I shoot a board from 4 m and its low .also the rubber inside the wide slot will be changing position after each shoot ,first move to second and second come in front I pull rubbers according to each position (hope this explanation clear for someone using wider slot) . likely I shoot the mackerel when it was near but missed many far fish ,I am planning to return to classic age 16 mm rubber cut at 3.3 :)

  • You have to eliminate all possible factors.
    1. Check shaft for straightness.
    2. Remove flopper and take shots without it.
    Although with the above two if there's a problem the gun will be erratic, not just shoot lower, because the shaft spins. Are you accurate on the horizontal plane?
    3. Try 7mm shaft.
    4. Try shorter shaft.
    5. Try one band, then add the 2nd band.


    The logic is if you're shooting low either the gun is underpowered so the shaft is slower and will drop more before it reaches the target, or overpowered so the muzzle kicks up from the recoil bumping up the back of the shaft causing it to take a lower trajectory.
    Heavy shaft (larger diameter and longer) will create more recoil.

  • 1-95 cm with 7.5 mm spear 130 cm with 33 cm overhang , rubber : 2*14.5 small ID 380%
    2-120 cm 7 mm spear 150 cm with 33 cm overhang ,rubber : 14.5 small ID 360% ,14 small ID 380%


    test them this morning and results was really bad,in the beginning I was thinking about my design why the spear won't penetrate the target at 4 m ! it just hit then bouncing ,I found out he problem when I add a third rubber to the gun ,it shoot very strong and accurate @5 m ,I can't understand why these small ID rubbers cut at 380% not work as everyone showing in the youtube ! I have to go back to the classic way and use 16mm cut at 315% -330% ,also I will use the rubber I purchase from you DAN year ago 16 small ID I ll cut 290% for the 120 and try 2 rubbers for performance .

  • 380% may be a little too much. with multi band guns i try to stay around 315%-330% stretch...using 16mm rubber as well as small ID 14mm rubber.


    Low shots and loss of energy could be caused by muzzle flip and shaft whip.


    Try to find that sweet spot where the shaft can handle the force of the rubber without bending (that's what she said):D


    I find railguns and wood guns will perform well with this band stretch, where i believe enclosed tracks can handle a bit more force and not whip....it is not needed. If youre using a wood gun or enclosed track, dont overpower it, utilize the mass of the gun to your advantage: reducing recoil.


    also 33cm seems a bit long for over hang especially using a 7.5mm shaft. this may be causing the shaft drop


    Im assuming 380% is counting the relaxed rubber as 100%.



  • what s your recommendation for spear OH ? for both 7.5mm and 8mm

  • Sometimes it is difficult to achieve the proper Shaft / Band configuration


    If shaft not damaged then this may give you idea.
    http://youtu.be/FSK4HkkimXk


    I have used that video ,either the band i bought is bad quality or the video made in pool is ideal (not considered sea currents and environment ) ,but whats the reference points for 130*7.5 mm? classic 16 mm rubber .

  • I have used that video ,either the band i bought is bad quality or the video made in pool is ideal (not considered sea currents and environment ) ,but whats the reference points for 130*7.5 mm? classic 16 mm rubber .


    Equilibrio gomas – varillas | GuiaPescaSub






    Shaft 7.5mm x 170cm = 578gr


    Bands 13.5-14.5mm (Z) for shaft 578gr = 370% stretched


    Bands 16-17mm (A) for shaft 578gr = 350% stretched



    Espero te ayude.

    Un Hombre tiene que creer en algo.......
    Creo que me iré de pesca!!!

    The post was edited 1 time, last by Josediaz ().

  • what s your recommendation for spear OH ? for both 7.5mm and 8mm


    I like to keep shaft overhang to a minimum, especially using heavier gauge shafts (7.5 and up) this will keep your gun from being nose heavy.


    You'll have to figure the exact length of overhang out on your own, find whats comfortable for you and the gun you are using.


    In general pipe guns ( 26mm id carbon fiber tubes).


    7mm shaft = Barrel length + 40cm
    7.5mm shaft = BL + 30cm
    8mm shaft = BL + 20-30cm ( I dont recommend going this thick on circular barrels, unless it is a polyplast, demultiplied or single roller)

  • after a year of gaining experience

    6,6.5 + 40 gun till 100


    7mm shaft +30cm gun till 100

    7.5mm shaft + 25cm gun 110 to 120

    8mm shaft = + 23cm gun over 130

Create an account or sign in to comment

You need to be a member to leave a comment.