Very nice shooting!! If the barrel has been in for a while they can be stubborn to remove!! Try soaking it in Kroil. Clamp the receiver, not the stock, in a padded vice. Mine have a notch in the bottom of the barrel, I don't see that on yours, then I put a non marring punch in the notch and tap it with a hammer to loosen things up. But, if there's no need to take it off just leave it, the threads tend to wear out if through use.