Anyone know if STX barrels will fit in FX Royale?

Hi, yesterday I put a STX barrel from Krale nl. (now out of stock) , and I had to put it in my lathe , take a small cut to get it into the action. I'm not sure it will be increase the accuracy.Moreover, I'm a bit upset to see how the barrel , which is much lighter than the original, droops when you put a finger on the tip .Take a look at my topic 

Mike

What is the OD of stx .22 pellet liner from top to crown. Is it 10mm. Anyone?. Thanks. 

Thank you sir Glem.