Question about FX barrels

[Javichu]

I have a Dreamline Tac Compact .22 with a 350mm STX barrel currently set to JSB Heavy at 800fps. If I changed the barrel for a 500mm STX superior without changing any configuration, how many fps would it increase approximately with the same pellet?.

 

[Odoyle]

Probably Around 70fps.

 

[nervoustrig]

It depends on the state of tune. If it is currently adjusted to the velocity knee for reasonable efficiency (~1.2fpe/ci), the estimate from Odoyle sounds pretty reasonable. It’s always a good idea to re-tune for a barrel change to achieve the best consistency (ES).

 

[TMH]

In addition to the accurate advice given above, you might also think about adding an FX Power Plenum if you go to the longer barrel, for a potential additional boost in muzzle velocity, perhaps at a lower regulator set point (giving more good shots per fill). The PP's don't seem to help as much in shorter barrel configurations, but start to make a real contribution as the barrels increase in length.

 

[srtmat]

If you retune it for max power you should see about 35-40fps increase for every 100mm of added barrel length.

My .25 Crown Continuum 150 from factory.

•380mm PW-Max 850-855 with 25.4gr

•700mm PW-Max 995 with 25.4gr

An increase of 140 fps from 320mm of additional length. 43.75fps per 100mm

 

[Javichu]

In addition to the accurate advice given above, you might also think about adding an FX Power Plenum if you go to the longer barrel, for a potential additional boost in muzzle velocity, perhaps at a lower regulator set point (giving more good shots per fill). The PP's don't seem to help as much in shorter barrel configurations, but start to make a real contribution as the barrels increase in length.

It carries the 17cc Dreamline plenum.