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All About Guns What's your weapon of choice, and why? Discuss the beloved speargun here!

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Old 05-28-2014, 04:17 PM   #16
Cyprus_Spearo
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Re: Shooting low..

What bands do you have at that configuration? and at what percentage stretch?
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Old 05-28-2014, 05:08 PM   #17
willstroo
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Re: Shooting low..

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Originally Posted by Cyprus_Spearo View Post
What bands do you have at that configuration? and at what percentage stretch?
Video configuration, single 18mm roller, around 250%-300%
Video configuration with tightening pulley system, single 18mm roller, around 300%-350%
New configuration, double 16mm roller with pulley system, around 300%-350%

I dont know if the pulleys are necessary for the twin 16mm rubber, I can load by other rollers with plenty of power. But its already all there, glued on etc, so may as well

Just hope it doesnt break in my face
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Old 06-03-2014, 05:10 PM   #18
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Re: Shooting low..

You really must do some target shooting. If you don't check with a target, you may be building supposition upon a falsehood - and waste a lot of time to come up with a negative outcome. I use a square of chicken wire, plastic grid for a target - and I can tell where the spear goes by looking at the shooting line. There are threads on target construction elsewhere in the forum.

The next question is how much flex in a barrel is too much. If you lock the butt end in a vice, and push on the muzzle, most stocks will bend some distance - but how much bend it too much? Personally, I don't know, but I do know that guns with some flex can shoot perfectly flat. Some of my wooden stocks will move an inch or so from side to side at the muzzle but, when loaded, shoot perfectly.
If I remember properly, in his book, Terry Maas suggests that if the bow in the stock (when loaded) has an amplitude of 1/8 inch or less, its not worth worrying about.
Maybe other forum members can contribute?

Ric
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Old 06-03-2014, 08:19 PM   #19
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Re: Shooting low..

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Originally Posted by willstroo View Post
This one:
DMart Apex Carbon Rail Barrel
Item No: CBRL-H140

http://www.speargun.com.au/barrel/index.htm

taiwan sports shits !

double barb heavy tips shit

underpowered band
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Old 06-04-2014, 07:25 AM   #20
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Re: Shooting low..

IMO there are 2 very good methods to see why your spear is hitting low.
1.Fastest and most accurate. Rig up several GoPros along the spear line of flight to record what the spear is doing, starting with frames of the spear in the gun as the spear begins to exit the gun and then subsequent picture frames during the spear flight to the target.
2. Slower, way less expensive and less complicated method is to shoot at an even surfaced foam target at increasing distances from the muzzle, beginning at the shortest distance from the muzzle that the spear is clear of the gun and then increasing distances out to the limit of your expected target or spear wrap line. With this consistant thickness foam target you can see how the spear is orientated in the foam and to see when/if the tail of the spear is orientated higher than the point of the spear in the foam block. (A net target will not work for this spear tail high test). If the spear tail and point are parallel/horizontal throughout the spear flight, often times the cause of low hits are not enough power for the spear weight/target distance or the spear line is the problem. (You can eliminate this spear line variable by freeshafting into your foam target several times).
If the spear tail is elevated into the first closest targets to the muzzle,
a. then muzzle "flip" may be one of the low hitting culprits.
b. very short bands or excessive spear overhang or thin spear "under splined" for the power can cause the spear to "flex" and begin its flight from the gun in a nose down attitude.
c. Another common cause is the spear flopper steering the point of the spear down.
d. Improper aiming/sighting is another low hit cause.
e. Improper trigger/grip technique is another. There is much more but these basics should help.
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Old 06-04-2014, 08:28 PM   #21
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Re: Shooting low..

Quote:
Originally Posted by Ric.Fallu View Post
The next question is how much flex in a barrel is too much. If you lock the butt end in a vice, and push on the muzzle, most stocks will bend some distance - but how much bend it too much? Personally, I don't know, but I do know that guns with some flex can shoot perfectly flat. Some of my wooden stocks will move an inch or so from side to side at the muzzle but, when loaded, shoot perfectly.
If I remember properly, in his book, Terry Maas suggests that if the bow in the stock (when loaded) has an amplitude of 1/8 inch or less, its not worth worrying about.
Maybe other forum members can contribute?

Ric
Quote:
Originally Posted by z1taz View Post
taiwan sports shits !

double barb heavy tips shit

underpowered band
Quote:
Originally Posted by hau View Post
IMO there are 2 very good methods to see why your spear is hitting low.
If the spear tail is elevated into the first closest targets to the muzzle,
a. then muzzle "flip" may be one of the low hitting culprits.
b. very short bands or excessive spear overhang or thin spear "under splined" for the power can cause the spear to "flex" and begin its flight from the gun in a nose down attitude.
c. Another common cause is the spear flopper steering the point of the spear down.
d. Improper aiming/sighting is another low hit cause.
e. Improper trigger/grip technique is another. There is much more but these basics should help.

Thanks so much for all your help, I think from my observations so far that the problem may have a few culprits:

Underpowered
Too much shaft overhang / Too heavy a tip
Maybe too much flex in the barrel, which im not 100% on

You can see the shaft bending in the video.. So i am currently changing to a double roller, i have all the stuff to change already so its just a matter of finding the time.

Then im going to shorten the shaft and switch to a drilled flopper, i have a local spearshop who are brilliant at helping me out.

Thanks again!
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