I use both of Brownell's fixtures, the barrel vise with aluminum bushings (and rosin), and the action wrench. For removal, I've NEVER had a problem with Remington receivers. What I do is mount the works so the handle to the action wrench is pointed up and take a piece of 1 1/4" square brass barstock (it's what I had laying around and works VERY well) about 2 1/2 feet long. Wind up and hit it a good fast stroke. Using a heavy slow impact from a mallet is nowhere near as effective as a higher speed impact from that brass bar. It knocks them loose with one strike. I did have to swat a Howa twice, and there was an old Mauser a friend brought that was very difficult, but even that one started to loosen after the 2nd or was it the 3rd strike. That was a barrel put on by Ackley himself...I don't know how he torqued in on as hard as he did, but it was so substantial the shoulder of the barrel was flared out on the action face.
Fast sharp blows will break them loose and be warned, if the barrel is NOT one of the 'tight' ones, be ready to stop that wrench handle as it will spin a good 3-4 turns after the first blow. I haven't had any spin themselves off yet, but there was one or two that were close.