Shaft length

[pecky762]

Hello all

Was wonder what is the shortest length spear people have run on a Rob Allen 120
Closed muzzle. Wanting to run a shorter spear for less overhang.

Cheers

 

[hteas]

You probably need to go with a 150 if you are using a 6.5 dia shaft. If you go with a thicker shaft you can get away with a shorter length. I use a 140x7.0 on myRA 110, but a 140x6.5 shaft developed enough shaft whip to make a lot of noise and accuracy suffered substantially.The basic problem is that the shaft can develop a harmonic that causes the whip.

 

[pecky762]

You probably need to go with a 150 if you are using a 6.5 dia shaft. If you go with a thicker shaft you can get away with a shorter length. I use a 140x7.0 on myRA 110, but a 140x6.5 shaft developed enough shaft whip to make a lot of noise and accuracy suffered substantially.The basic problem is that the shaft can develop a harmonic that causes the whip.

Was thinking 7.5mm shaft. And twin 16 or 14 rubbers. 120 takes a 160 shaft was looking at 150

 

[hteas]

My guess is that it would work. Just don't overload it. I use 2x14mm bands with a 3x stretch.

 

[Nicholas1986]

I’ve used a 150x7mm Shaft with 2 x 14mm bands on a 120 RA gun already. Had no issues. Can’t go any lower as the flopper would end up on the muzzle/gun.


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[pecky762]

I’ve used a 150x7mm Shaft with 2 x 14mm bands on a 120 RA gun already. Had no issues. Can’t go any lower as the flopper would end up on the muzzle/gun.


Sent from my iPhone using Tapatalk

Thanks for that