FX Crown 380mm barrel

Mine with factory pellet liner (not superior) probably shoots the best with the 18.13. I do believe the liner was designed around and even had the choke adjusted while using those pellets. I also use 16gr hades, and I can't tell if one shoots better than the other.... I think they have pretty much identical engagement with the rifling. Just the 16gr under the skirt is less filled in. Both a notch or two above my best expectations. 920fps w/ 18.13 and 960fps w/ 16gr, using ported barrel inlet. I saw someone else getting amazing groups with H&N .217 slugs thru the new superior version of this 380mm barrel as well.

16 and 18 depends what you wanna tune for and loudness 

18 JSB, the 380's need 150 bar reg to get anywhere near a resonable velocity even with the lighter pellets.

Mine is shooting 18gr @ 920fps with 125 bar just installed new gauges on it as well. I knocked one, and was getting bad readings. I get the same power at 135 bar, and 950fps at 130. Barrel inlet is ported. But was only a 50fps gain over the factory tune. Mk1 continuum has more appropriate valving for 22 caliber 

PerkyVal, 

The 380mm shoots a lot of pellets/slugs well, just at lower speed than the longer barrels. I quickly shot a target at lunch using 2 pellets and 1 slug out of my MK1 w/ 380mm superior and started another thread to give you(and others) a rough idea. Check it out. You can choose your ammo and fine tune it down for even better performance/accuracy. 

Good luck

I just mounted my 380 a while ago. I’m struggling to shoot anything under an inch at 50 yards. Any tips? I’m using the JSB 25.39s, .25 cal.