FX FX Crown 380mm barrel .30 cal pellet speed .

[aldea6]

Hi, I put a 380mm barrel on my Crown MK1 in .30 cal . Reg pressure is 150bar , HST on Max . Shooting JSB 44grs , the speed was only 740 FT/s , which seems a bit low for me . I know that short barrel means lower speed . Moreover the MK1 has a small plenum , but I would like to know if my settings are correct .
Thanks

 

[Long_Gun_Dallas]

Cant recall what my mk1 does with factory hammer and tune, but I only have a 600mm 30 cal barrel. Does 925ish fps with a 7gm hammer weight @ 150 bar. Barrel has some port work done as well which helps a little.

 

[aldea6]

Cant recall what my mk1 does with factory hammer and tune, but I only have a 600mm 30 cal barrel. Does 925ish fps with a 7gm hammer weight @ 150 bar. Barrel has some port work done as well which helps a little.

Yes maybe a heavier hammer will be an improvment ; I think mine is standard . Thanks

 

[Corvid_hunter]

It should shoot about 120-150fps slower than it would with a 700mm barrel at the same tune.