Thanks much!
This forum has saved me headaches already...
swapped out a muzzle brake, the soft hammer approach wasn't dislodging the original. Do I leave it? Bring it to a gunsmith?
Then came across a post by somebody else who already had the same problem. Liquid Wrench, a steel punch, and a few light hammer taps, and I'm IN! (Or out, depending on how you're looking at it.)