TargetTalk

So Im having issues with ejecting cartridges after shooting my .22 rifle. I had to use unusually much pull on the bolt to get it out.
I usually clean the bore after about 250-300 shots with Boretech rimfire solution. So Im guessing this is so called carbon ring buildup that makes the spent cartridge hard to eject
If thats the case - do you have recommendations how to clear this carbon problem?

Solvent and bronze bore brush. I take a 6mm or .25 bore brush, bend it to a right angle, tape some to protect my fingers, and go for it.

As recommended above, a bronze brush and solvent will clean most barrels. Leave the solvent to soak into the fouling for 15-30 minutes helps; most solvents are oil based so this won't cause any harm. A strong ammonia solvent might, but who uses those for a .22? Even so you may need a few cycles of soaking, brushing, and patching dry. If the barrel is really cruddy, careful use of a paste cleaner (I use VFG) can save time.

However, it's not always the chamber that causes sticky bolt opening. Clean the bolt and breech too. The wax coating on the bullet gets everywhere. The recess for the extractor claw(s) get(s) filthy, enough that the claw can't hook over the case rim; on most target rifles the claw hooks over as the cartridge is jammed into the chamber. Remove the claw(s) too if you can and thoroughly clean those.

Sometimes the bolt can be stiff when it's dry. Most bolts cock as you lift the handle; an angled surface inside cams the firing pin back. Strip the bolt, clean it, and lubricate; don't soak the bolt in oil, it needs a little grease on the cocking cam.

I suspect I've caused damage with ammonia solvents before, I believe they react with the bronze brushes (you're generally only supposed to put them on patches) and they create copper salts which can then cause corrosion if not removed.

Unless you have copper fouling I don't think there is any reason to use ammonia and plenty of reasons not to.
Some cleaning solutions which don't state they contain ammonia in fact do, you can find it on the SDS.

If you dry-fire a rimfire without an empty case in the breach, there is sometimes the danger of peening the breach where the firing pin hits it. This can cause a small metal intrusion into the chamber which can interfere with clean extraction.

Bob