Fwb-601 velocity issues

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Bob85
Posts: 4
Joined: Thu Aug 04, 2022 9:15 am

Fwb-601 velocity issues

Post by Bob85 »

Hi all,

I have a fwb-601 air rifle, and i have some pellet velocity issues. It produces 184,4 meters/second with the 0,475 grams jsb exact rs pellet, and i need to downgrade it to 178-180 meters/seconds to fit the hunter field target rules in my country.
There is a hammering spring which is adjustable and this may be the solving of the problem, but I don't know how much adjust it needs. (There is a video in youtube, where mentioned: https://youtu.be/KulIF-HsoX 12:37) I only know for loosening I need to turn the screw counter clockwise, but don't know how much. What happens if I turn too much out, or in?
Any leads is appreciated.
Th.
Posts: 90
Joined: Sat Mar 04, 2017 2:09 pm
Location: Netherlands

Re: Fwb-601 velocity issues

Post by Th. »

I would chose a heavier pellet. It bring’s down the velocity and it will be less effected by the wind.
Bob85
Posts: 4
Joined: Thu Aug 04, 2022 9:15 am

Re: Fwb-601 velocity issues

Post by Bob85 »

Th. wrote: Thu Aug 04, 2022 10:00 am I would chose a heavier pellet. It bring’s down the velocity and it will be less effected by the wind.
That is the other way which i will try but this is not only about the velocity, but the energy what is 7,5 joules ( the law limit) and there is a little tolerance in it.
Th.
Posts: 90
Joined: Sat Mar 04, 2017 2:09 pm
Location: Netherlands

Re: Fwb-601 velocity issues

Post by Th. »

spektr
Posts: 887
Joined: Mon Jan 21, 2013 9:53 pm

Re: Fwb-601 velocity issues

Post by spektr »

unless you adjust the powerplant, the pellet weight will only affect velocity, and total energy will remain where it is now.
Bob85
Posts: 4
Joined: Thu Aug 04, 2022 9:15 am

Re: Fwb-601 velocity issues

Post by Bob85 »

spektr wrote: Fri Aug 05, 2022 12:12 am unless you adjust the powerplant, the pellet weight will only affect velocity, and total energy will remain where it is now.
That is the question, how to do it. Is's ok to turn the hammering screw but how much for not to make another problem.
spektr
Posts: 887
Joined: Mon Jan 21, 2013 9:53 pm

Re: Fwb-601 velocity issues

Post by spektr »

Turning the hammering screw is not going to work. This is an SSP gun, not a Pcp gun. 100% of all air compressed is discharged each shot. There is no regulator or reservoir feeding the gun that would make the gun susceptible to hammer spring adjustment to change shot volume. Shot volume is fixed by the powerplant stroke X diameter. If you need to change the velocity, you modulate the pellet weight OR get into the powerplant and start making very tiny adjustments to remove shims installed at the factory to regulate stroke distance to get the velocity desired with the test pellet.
Bob85
Posts: 4
Joined: Thu Aug 04, 2022 9:15 am

Re: Fwb-601 velocity issues

Post by Bob85 »

spektr wrote: Sat Aug 06, 2022 9:45 am Turning the hammering screw is not going to work. This is an SSP gun, not a Pcp gun. 100% of all air compressed is discharged each shot. There is no regulator or reservoir feeding the gun that would make the gun susceptible to hammer spring adjustment to change shot volume. Shot volume is fixed by the powerplant stroke X diameter. If you need to change the velocity, you modulate the pellet weight OR get into the powerplant and start making very tiny adjustments to remove shims installed at the factory to regulate stroke distance to get the velocity desired with the test pellet.
Could you please suggest a pellet weight which is enough heavy to reach the desired energy? I'm a bit noob for this.
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