If you sand out your barrel channel make sure you use something that is a smaller diameter than the barrel.
I find your average concrete pin fits sporter barrels nicely.
I also mentioned the heat...
And as for the copper--maybe listen to marksman more than me with his "copper equilibrium" bizo...
I had (have) an old (some 40 plus years) remington in 22-250 that never ever ever had the copper cleaned out of it.
It took me bludy months of scrubbing & soaking a couple of times a week to clean out the copper, then i also got a brush in the throat to get some compacted carbon out too...!!
I was so proud of myself
...you shouldv seen how shiny the bore was...!!
I was so excited & couldnt wait to shoot my baby again with her new makeover--then i shot it...
i rooted it mate-
-it was a .6"-.7" shooter & i turned it into a "minute of shed" outfit...-it was never the same & doesnt shoot anymore.
Every now & then i see it in the back of the safe & think it'll be better now...
I load up a few & take it to the range & it cracks a .7" group & get all steamy eyed & think to myself "ah my baby's back, i love you & miss you so much"...
I then i load some more & take her next time & it throws a tantrum & just chucks poo everywhere...
Anyway, what were we saying...ah yes...copper equilibrium. ..!!
The man who knows everything, doesnt really know everything...he's just stopped learning...