Help with slug set up

[easyridemm]

I recently bought an FX King in .30 caliber. The gun has a 600mm barrel and has the superior heavy liner with a 1:16 twist Installed. The regulator seems to be set somewhere around 130 bar. It is difficult to tell as the gauge is nowhere near correct. (The gauge reads 108 bar) The gun shoots the 44.75 grain JSB pellets very well around 975fps. Groups of 1 1/4 “ with the heavy liner. I bought a sample of Zan slugs, 45 thru 68 grn., some NSA 47 grn., and some 44.4 FX Hybrid slugs. I shot @ 100 yds., shooting 5 shots at each with a different weight and type of slugs. My results were disappointing to say the least. The only thing that would group were the 44.75 grn. Pellets. (1 1/4”) The slugs all shot a group between a baseball and softball. My plan was to find a slug that shot the best, then try to tune the gun for that particular projectile. My speeds ranged from 970 with the 45 grn. to 835 with the 68 grn. Does anyone have any ideas on how I can get these slugs to group? Thanks for suggestions as I am lost.

 

[Solo1]

Well im not really a fx guy but first thing you mist do is get a new reg gauge so you know where you are or shoot it down to see where you drop velocity and compare bottle gauge to reg gauge. Then pick i weight zan slug you have a lot of and set velocity to say 970 and work down to say 890 hopefully you will find a velocity it likes. Make 970 near your max on gun settings then use your wheel to go down. Hope this helps or someone with same gun chimes in

 

[6gun]

I can relay what I've found to work, and the common reg pressure for guns that my group of buddies have stumbled upon.

Firstly . The guns I've worked with are all 22 and 25. No matter the model of fx they all start to perform better at 150 bar for slugs 380mm 500mm, 700mm, or either caliber. Also we all use one of the chinese digital guages for the final reg pressure, not a sekmet and none of us have had issues.

My 700 was a harmonic tuning monster vs the 380s and 500s, and the combo of reg pressure and muzzle device weight closed my groups. I recommend taking the velocities and pressures people recommend, or specific power figures under advisement but don't marry yourself to them. Each gun is like a musical instrument and it will tell you where it's happiest. Leaving some fpe and sometimes 100 or more fps is sometimes the consequence for precision. Its really tough to back away from on-paper spec thoughts , but I've had to learn to ignore what I want mathematically and see what the gun is capable of delivering in it's current tune, precisely, and use that to my advantage.

After 50 fpe you an kinda handle almost anything, and your being 30 cal means you have that covered nicely. A 30 fpe well placed shot anchors turkeys and skunk-coyote fwiw.