Cleaning from the muzzle on any firearm can put a burr on the crown which can and quite often does adversely affect accuracy.
How does this burr happen, exactly? Have you experienced it?
I have not experienced a loss in accuracy, is all I’m saying. But I only have two old guns with years and years of cleaning from the muzzle end, which I can’t really draw a conclusion from on their own. However, I’ve never seen an example of this, either. Messed up crowns, from dropping on muzzle, yes, a few. But I have no examples of a burr on the crown due to a cleaning rod.