Yes....and no. "Hand lapping" with a soft brush or patch may polish the bore, but it can also round off the edges of the lands if done to extreme and seldom gets into the corners of the grooves. True hand lapping uses a tight fitting lead lap which, if properly used, can greatly increase the quality of the bore. This is how custom barrel makes finish their barrels. Time consuming, but quality costs $.
Firelapping can smooth up a barrel, but it can - and often does - open up the throat, sometimes significantly. It also can increase the rest of the bore's diameter. The bullet type, grit size and load velocity all effect the way firelapping performs. I've used it in moderation to smooth up a few barrels, but I normally used very fine grit and mild loads. If you try it, follow the directions EXACTLY.
