Boretech C4 is highly recommended for removing the carbon ring in Rimfire firearms. Soak a patch in it and push into the chamber just enough to be where the carbon ring is. Just longer than a 22lr case length. Let it sit for 10 to 15 minutes and then use a brush to clean it off.

You can reduce the build up by cleaning the barrel with an oiled patch after every use.

Why would you say that ?

While never experiencing it on a smaller caliber I have witnessed it on a magnum caliber of my own, as well as on 2 of my friends rifles of the same caliber. Our barrels approached a similar round count and we experienced massive pressure spikes and 100fps in speed jump. Barrels were cleaned with every substance we could find and were squeaky clean but the issue remained. After advice from a well known barrel maker who had experience with carbon rings in larger calibers we cleaned with a product called simichrome, the first 2 inch of barrel. The amount of carbon that came out was unreal. The issue was resolved. So it is a real issue. in this particular rifle we were running 250gr bullets at close to 3000fps

I dont shoot 22 enough to even clean the gun let alone experience it first hand. I do know of a shooter who competed internationally and experienced it with 22, shooting large volumes in training. Your comment inferred that carbon rings dont exist/occur.. they do, and can in any calibre

just because you havent seen it then its not true?

Because others have, because its documented by many, check online there is numerous articles with borescope pictures, chrono speeds, tgt groups etc.

<MOD SNIP>

I don't have a bore scope so I've never seen a carbon ring. It seems logical that carbon would deposit heavier just ahead of the case. When cleaning my 22s I swab out the bore with a few patches to remove crud. Then I use KG1 on patches and get the bore well soaked. I'll also stick a KG1 soaked bore mop into the chamber so if there's a ring of some description it'll get heavier treatment. I'll pull that out and agitate the KG1 with a run of a nylon brush once in a while to help the KG1 do it's job. After that I'll clen out the bore and run a patch with Brunox oil and then a dry patch after.

Whether I'm at nothing or not I don't know. As long as I'm not doing any damage, what's the harm?

Edit - my understanding is that a carbon ring is detrimental to 22 accuracy as it tightens the bore and since lead is a dead metal the bullet is squeezed through the ring and is narrower than the rest of the bore. But then bores are not uniform in diameter anyways hence benchrest barrels being slugged or air gauged to find the tightest point to cut the barrel to.

It'd be interesting to find out how much barrel bore dimensions vary by and then how much of a carbon ring would need to develop to make it the tightest point in the bore.

I'll be over here in the nerd corner if anyone is looking for me!

if anyone is visiting the States a marvellous product is Thorroclean. It’s a 2 part cleaner. It will leave a barrel borescope sparkling clean.