Just be careful and watch what you're doing. Done it numerous times and my rifles shoot well, very well at that. Thing about how button rifling is installed, so saying it's not good for the bore is just plain nonsense. I don't make it common practice coz it's not needed, just rifles I acquire that been neglected.
Sorry to say, with all due respect, that I do not agree.
First, a rifling button does match every area in the lands and grooves almost perfectly. But anyway,
Whatever you carry under load in that barrel and how ever you carry it inside that barrel, should it contains something harder than the barrel steel, and whatever the size of the ""harder than steel"" particles, and whatever the amount of care applied, the Op IS to remove steel and or scratch the barrel.
I have been polishing chrome lined and hard-thick anodized alumina air cylinders for years, so experience makes me definitely let this kind of operation to the "grit masters" at the barrel maker shop.
Except for some WW2 barrels looking just as freshly ploughed, but that's a different story.
As far as I can remember, the "grit masters" are using cast lead laps matching individual barrel's land/grooves as close as it is possible, have them loaded with successive abrasives of the right size AND SIZE DISTRIBUTION, lap the surface and create the inside cone of the barrel adjusting the number of strokes here and there.
Using a patch carried by a jag can obviously not apply the same amount of pressure on lands and grooves, and will apply for sure ZERO pressure where lands meet grooves, with everything possible in between.
Aka the Op will lap mostly at the center of lands, less at center of grooves and barely not where it comes to land/groove ""border"", where carbon is the most tricky to remove.
My mind is that it is very important to use, if needed, an abrasive paste with particles harder than copper, harder than carbon, but softer than steel. The pumice in JB is just that. And you just can't have it carried under the same pressure/load in every place (lands, grooves) of that barrel.
In between Flitz and Iosso, one is just on hardness edge and the other behaves like a steel abrasive, I never used them, can't remember which is what. Clearly remember competitors shooting numerous sighters after using one of the twos.
Personally, I own one small jar of JB since the 90's. Used almost 2/3 of it.
Anyway, bench rest is a free country.