I have a Spike's dedicated 22 upper. I does not work worth a crap. I have two friends with your kits that are very happy. I was wondering what it would take to get your guts in my dedicated upper.
This has been discussed many times here lately.
You will have to use your Spikes collar which may need a minor amount of fitting on the CMMG rails. Mine worked without any fitting.
Problem here is if the collar is loose on the extension, and many are, it will cause a multitude of feeding and ejection issues.
Or you can have the barrel extension turned down to .460 and have the groove cut into it for the complete CMMG BCG that snaps onto the barrel with a spring detent.
What Dave N said, +1. If you have a tight collar already, it should work with
the addition of the CMMG Bolt. Redtazdog could turn a CMMG Conversion
Chamber Adapter into a dedicated collar to fit tightly to your Spike's Barrel
Getting machine work done on it doesn't keep the price down. Might as well start from scratch.
And that is the other option. Sell the Spikes. Some guys love a challenge.