JSB jumbo Monster in FX Royale 400 .22

I shot them out of my FX Royale 400 equipped with BSA barrel. 

I achieved 875 fps maximum. These pellets are extremely accurate up to 55 yards at 875 fps. 

For longer rangers like 80+ yards, these pellets need more than 925fps. 

My RAW with BSA barrel at 935fps shoots these pellets extremely well even beyond 100 yards. 


Thats nice, i think hes asking about how they shoot in smooth twist. 
 
Without a chrony would be tricky to tune it, but i would lower speed by turning the hammer spring adjuster counter clockwise (unscrew) 1 full turn.

Its a 5mm and most are threadlocked from factory and might need heat. You can use this as your power control. It will give you adjustability of power for each reg setting.

1545585427_21200515875c1fc313bc41e8.89076021_20181223_091437.jpg


That said, if youve never adjusted anything youre probably around 35fpe now with the stock settings. So maybe try a full turn up take some shots then do a full turn down.


 
If you want more power, you can get the SHP valvepin complete, valve seat and hammer weight from the Royale 500 and increase reg pressure then you should get 40-45fpe. I have a Royale 500 and bought the pellet probe, guide and barrel from a Royale 400 so I can swap caliber I got 45fpe in .22 using the 400's barrel. It's a fantastic platform, very easy to work on and incredibly reliable. 

I can't find the SHP valvepin complete on this diagram but your local dealer should be able to help you if you wanted to go this route.

http://www.fxairguns.com/wp-content/uploads/2015/10/Royal-Drawing-and-Partlist.pdf

I recently bought a Boss breech block have a look what that's capable of using a mix of Royale, Boss and an Impact part.

https://www.airgunnation.com/topic/boss-in-a-box/

Try H&N Baracuda Match, they'll shoot well for you right now.