FX Any Starting Numbers I Should Try for my Regulator to shoot a 21gr slug at 950fps and a 25.4gr slug at 960fps?

[recheck30]

I have a stock standard FX Maverick and I have been shooting some JSB Knockout 25.39gr slugs at 50 yards. I want to increase the speed on them up to 940-960ish to see if I can get better accuracy out of them. They are currently shooting at 860fps.

I don't know where to start and I don't want to have to spend all day guessing on regulator numbers if someone has a suggestion.

Thank you in advance.

 

[nervoustrig]

Energy is proportional to pressure.

You're currently at 860fps with a 25.4gr slug so 41.7fpe.
You want to be at 950fps so 50.9fpe.
Going from 41.7 to 50.9fpe is an increase of (50.9-41.7)/41.7 = 22%

Try increasing your regulator pressure by about 22%. Note this all assumes you are already nearly maxed out at the current regulator pressure. If not, start by adjusting the hammer spring until the gun is operating at the velocity knee which is about 97% of the maximum velocity you can achieve.

 

[NAProf]

I have a stock standard FX Maverick and I have been shooting some JSB Knockout 25.39gr slugs at 50 yards. I want to increase the speed on them up to 940-960ish to see if I can get better accuracy out of them. They are currently shooting at 860fps.

I don't know where to start and I don't want to have to spend all day guessing on regulator numbers if someone has a suggestion.

Thank you in advance.

Which barrel are you using? A 500 mm barrel will require much different settings than a 700mm one. You also may have some accuracies issues if you push try too much air through the barrel.
Cheers,
Greg

 

[recheck30]

Which barrel are you using? A 500 mm barrel will require much different settings than a 700mm one. You also may have some accuracies issues if you push try too much air through the barrel.
Cheers,
Greg

I have the 700mm barrel.

 

[NAProf]

With the 700mm barrel I switched to the 13.16g Huma brass hammer weight, The stock hammer that game with my rifle was only 10g and had a 0.9mm head. The Huma has a 4mm head. I liked this combination much better than the heavier FX hammer with 13.2g and an 8mm head.

So with that hammer and the standard 56mm FX hammer spring I used the following settings:
JSB MRD pellets 910fps, SD 2 , ES 9, !st Reg 132 bar, 2nd Reg 97 bar, IHS 4.5mm, PW5
JSB Knockout slugs 935fps, SD 8, ES 25, 1st Reg 130, 2nd Reg 95, IHS 4.25, PW6
Javlin Gen 2 23gr slugs 950fps, SD 5, ES 19, 1st reg 140, 2nd reg 100, IHS 4mm, PW6
FX Hyrid slugs 960fps, SD6, ES23, 1st reg 140, 2nd reg 105, IHS 4.omm, PW6

Hope some of these might work for you.

Cheers,
Greg