Jim. I can't tell you what the velocity would be from a 10" bbl, however I have (It's in the closet somewhere but I would have to move so much stuff!) a .22 book that I have kept for years. I remember a test pretaining to bbl length. The .22 mag reached its maximum potential in a 12" bbl. From that point on it only gained a minimal amount for each inch of bbl length. So from that test, your 10" bbl should be very efficient. I have always enjoyed the .22 mag, usually in a 10" contender. don't worry about it, just take it out and enjoy it! Stay safe. 44 man :grin: