Barrel Polishing

This is a copy/paste of my reply on a prior thread on this topic. Most of it is relevant to your question but I’ll start by confirming what others have said about using a polishing compound as opposed to paper of some kind. 

I prefer to use a cleaning rod with ball bearings in the handle to allow the rod to rotate and follow the rifling, working in a linear fashion to help get into the inside corners of the rifling where lead is more likely to build up. Some folks like to spin it and they get good results too but I’m not a fan of that approach. 

I do it to every new barrel I touch. The idea is to smooth out the microscopic surface fretting left behind from manufacturing that tends to abrade lead. More strokes at the breech end and progressive fewer as you get nearer the muzzle. Something like 100 strokesis a good start…25 strokes to the first quarter of the barrel’s length, 25 more to half of the barrel’s length, 25 more to 3/4 of the barrel’s length, and then wrap up with 25 full length strokes. Do not overshoot and let it exit the muzzle because you don’t want to develop a bell mouth at the crown. Then clean the barrel and reinstall it and test.

In my experience, once you get a bore nice and smooth, you will not have to clean it nearly as often and it will be easier to clean when you do.

Like most folks, I use J-B bore compound and then do a finishing pass with J-B Bore Bright. Other compounds will work fine though, you just don’t want something extremely aggressive.

I cover this topic and a few other DIY accurizing suggestions in this article:

https://www.gatewaytoairguns.org/GTA/index.php?topic=130555
 
I would suggest using diamond paste 14000 micron or 18000 micron removing roughness in the rifling was the purpose of this thread I believe. For that we need some abrasive action to smooth out the high spots that tear out lead from pellets. That's done by abrasive paste (diamond paste being good example) and most often a barrel lap or in some cases cleaning patch or bore snake with abrasive in it. So, if we do that and make the rifling smoother it will not hurt/ruin but rather improve the rifling. Of course excessive lapping will expand the bore be careful and check the barrel frequently.
 
I may be being unnecessarily cautious but I’ve avoided using diamond abrasive on account of its potential to become embedded. My suggestion would be to only use it with a rod dedicated to this purpose. Working exclusively from the breech end, there’s not much cause for concern. Just saying I wouldn’t want to turn around and use the rod from the muzzle end where any embedded abrasive risks damaging the rifling at the crown.
 
Ive watched a video by Ernest Row himself preping barrel's with very fine jeweler's cloth which looks like sand paper....wrapped around a tight fitting bore mop! 

Several steps in different grits !

Think it was a Cricket barrel. 

Ive never done and only use JB products but he made it work....

James from Michigan

Here it is:



https://youtu.be/Gkg_2v2X3Ac


 
I've had great results with Mother's Aluminum Paste, I used a weed whacker line with a ball melted on the end. The barrel removed from gun no O rings, I packed the front of the barrel with paste and ran one loose patch thru several times. This particular ball needed three patches for a super tight fit. I followed up with double patches for three swipes, I then loaded 3 for a super tight fit and ran four virgin patches. I continued with virgin patches and mineral oil for about three more patches. From there I went thru about a dozen dry patches till there was not a speck of dirt or color on any patch. I then took Q tips with mono hot glued to the shaft and gently pulled them thru, not a strand of cotton snagged in the barrel, and the rifling was gently displayed when I pushed a .25 pellet thru with a 3/16 wood dowel. I don't know if I hit the barrel lottery with this gun, or it was the cleaning process. I did the same with a powder burner and more than happy with the results.