I’ve had 2 prefits that are great a 22 Creedmoor and a 25 Creedmoor both are 3/8” shooters I also have a match grade PacNor in 222 that isn’t that good so so any barrel is hit or missNot what anyone that has one on order wants to here.......... X caliber seems to be hit or miss. Some guys speak well of them with no complaints. I figure most barrels are OK but they sure seem to have higher dud rates than other established match barrel manf. I know for a fact gunsmiths have sent multiple barrels back for being out of spec. You may get a very good barrel Working up loads and shooting groups is the only way to really know for the end user.
There are enough people happy with their x-caliber prefits and blanks that have commented in xcaliber threads, if you do a search, to give you a warm and fuzzy feel. In the end, the barrel either shoots or it doesn't. Since you already ordered, its sort of moot. If it turns out to be a real shooter; for that setup it does not matter how many bad vs good barrels they have spit out.
For me personally, knowing what I have seen reported I would choose not to use them given the other choices out there.