I don't do any cleaning of the burn rings beyond a toothbrush and Hoppes then wiped off with cotton patch. It gets the heavy deposits off but the actual burn rings remain.

Just don't see the point removing them completely when they will come back immediately the next time you shoot it. For someone who shoots his guns, that's a waste of time.

This is especially for blue guns because if you keep scubbing the burn rings off constantly, the blue is going to eventually go with it. Now if you have stainless, then a lead away cloth would make removal pretty easy if desired. I just still have no desire.

As far as factory trigger pulls go, almost each and every gun will vary. I don't think there is a ton of consistency with today's production standards.