FX Impact M3 - barrel polishing

I have a .177 M3 FX Impact with a 600mm STX Superior barrel liner. It is accurate but the barrel needs cleaning every 150-200 pellets when the groups open way up. In order to do a good job cleaning, I remove the barrel and run through several felt pellets and patches with my patchworm/ballistol. I find this irritating as I can shoot >200 pellets in a session. I have several other air rifles and I can usually shoot 2-3 tins before I need to clean the barrel.



I’m considering polishing the M3 STX barrel liner with the hopes of it requiring less cleanings. I read the forum and several say “just keep shooting pellets through it and it will eventually polish". So far I have about 4500 pellets through my M3. I shoot only Air Arms, JSB or FX 10.3 or 8.4 pellets (un lubed and not cleaned and they seem to be very clean when new). Ideally I’d like to purchase a backup STX liner in case I make things worse.



I’ve read and watched the Orion Hunter’s barrel polishing video (uses a mild metal polish with a mop) along with Earnest’s barrel polishing video (uses polishing paper and finishes with a lathe). Since I don’t have a lathe, I was going to try Orion’s protocol. Wanted to check in to see if anyone has experience polishing the STX barrel liners and their post polishing observations. Thanks in advance.



Orion’s video



https://www.youtube.com/watch?v=vquzP0dGwN0





Ernest’s video



https://www.youtube.com/watch?v=Gkg_2v2X3Ac







JT
 
See here for a good discussion on the topic, including the benefits or detriments of using an in-and-out versus rotating action:
https://www.airgunnation.com/topic/barrel-polishing-5/

BTW, no amount of shooting pellets or slugs will polish a barrel unless we are talking about fire lapping where there is some kind of grit introduced.
 
I have 4 FX 177 barrels including a 600mm STX barrel for impact and I only cleaned one once due to troubleshooting and ended up cleaning didn’t do anything. I do polish the choke of the barrel with JB bore paste for about 200 stroke but I do that to all my barrels. I even switch between pellets and slugs, the shroud is always caked with lead dust when I change barrel, totaling got over 10k 177 pellets over as 12 months easy.

Not sure if polishing of the choke did anything but I really don’t clean any of my FX barrels on a regular bases. Pretty sure some of barrels/liners has never seen a cleaning mop outside of the initial polishing.
 
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115 yrds
 
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Very nice! I commend you on your results and marksmanship, but I don’t think it substantiates the claim that fire lapping is superior. It does have some advantages and disadvantages relative to other methods, and every situation is different in terms of the barrel’s initial state, the user’s tools and skills, time and effort invested, risks, etc.

Sometimes I polish using felts and abrasive, sometimes a poured lead lap, sometimes by fire lapping.
 
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If you have a really rough barrel you would hand lap it. With soft lead poured into barrel around jag. Use roating rod with bearings in handle. My Texan barrel was horrible I started with 120 grit .That's how premium barrels are lapped. Some after the barrel is reamed and after it is rifled. JB bore cleaner will remove lead and fouling but not tool marks in rifling. Fire lapping is just putting the lapping compound on pellets or slugs and shooting them through your gun. Yes it works but you may blow abrasive grit in places it should not be. I prefer hand lapping. I could easily feel the rough spots in the barrel with lead laps. Lapping barrels is old tech but works
 
Lapping a barrel with a hand poured lead lap is a highly skilled procedure. Not trying to dissuade you but probably only a good idea for the top 5% of air rifle owners as far as mechanical experience and aptitude. Read a lot before you try it and warm the barrel up before you pour the lap. Good advice on using a cleaning rod with a bearing. 120 grit advice as your first abrasive is Barbara Streisand IMHO.
 
Bruz barrels makes some excellent bench rest barrels in all calibers. I watched there pod cast and that's how I learned the grits there using for hand lapping. Hand lapping is not that hard if you already are used to melting lead or have a casting pot and a good rod . Try to polish outside of a barrel on a lathe and start with 400 grit and see how long it takes you to get a finish. Its the same as on the inside. 4140 chrom moly is hard. If your barrel is leading heavily you have tool marks. Light grit abrasive won't remove them. All premium benchrest barrels are hand lapped .They are much more perfect than are cheaper production airgun barrels and they lap them starting 120 grit after reaming and after rifleing. I worked in a barrel factory. Barrels aren't that complicated. Small calibers bores get drilled so crooked you can visible see. You know how they fix it..... Put it between centers and hit it with 10 pound hammer where the high spot is. Then put in cut machine and turn between centers. Barrels 30 cal and above had much straighter bores.