Any benefits???Easier to clean??Better accuracy?Thanks ahead for your comments,OB

Like most things; it depends. Some bores are lapped from the factory like Green Mountain and Colerain. If your bore is rough, then lapping will help. If it is smooth, then it probably won't. Smooth bores allow for easier loading and cleaning. Better accuracy. Definitely. Maybe.
What barrel do you have and how is the accuracy now?
If you have an old, rusted bore, then lapping will fix it, again, depending. I mean by a poured lead lap; do not use a patch on a cleaning rod to "lap" a bore; that will ruin it.

It is on a Encore and Omega with factory barrels.There were tight spots on both barrels when loading.I actually ran 6 loads with 320 grit today through both and both are loading and cleaning easier.I will run some 600 grit through them to finish them off.

I just realized you were asking about fire lapping; not lead lapping the traditional way.

I do not know if it helps but I firelap any gun I end up with, new or used and smokeless or Holy Black propellant.

Does it help?

No way to prove it, I don't think.

I do use a very mild abrasive and shoot 25 -50 rounds downrange in front of very weak powder charges, some hit lead projies the ground in front of my 50 yard berm and bonce on down range. I did say mild charges.

Well I ran 220 grit,320 grit and 600 grit through with lead bullets at 1,000FPS.Both load with no hesitation in the barrel when loading or cleaning so the tight spots seem to have polished out.Accuracy has also improved and it takes six patches to clean after I am done shooting.Well worth the time to do it in my opinion.I am using 110 grains of Blackhorn 209 Federal 209 Primers and a 250 grain Hornady SST in Sabot.I got a 1 1/2" 3 shot group at 200 yards with the Encore and a 3" group at 200 yards with the Omega.This is not a one time deal,but if I do what I am supposed to they shoot that well all the time.OB

That's the exact load I'm using in my Omega. It has worked well on the only two deer I've shot with that combination. One was DRT the other only ran about 30 yds before dropping.

I lapped the barrel on my savage .
Here's a pic of what my sabots looked like before and after hand lapping the barrel, took care of the zipper like feeling. and helped with the accuracy of the gun.

Its a short cut. just shooting will do the same thing..Its basically barrel wear..