Thread: how little reworking of the brass while reloading is necessary

Depends on the neck clearance of the rifle and the brass. Some rifles (normally target rifles) are chambered with a 'tight neck' which requires the brass to be matched - this can be by obtaining a certain type of brass or by neck turning the brass to a specific neck thickness. This means that the clearances are minimum on firing, which is OK for a target type rifle but not for a hunting or plinking rifle which might have to digest factory supplied ammo from different manufacturers.

Your friend may have just gotten lucky, and ended up with a rifle and brass combo that's on minimum specs already which is allowing the brass' neck to spring back after firing to adequately grip the next bullet without the neck needing to be resized down but this is uncommon. More likely with a factory chamber is that the brass has quite a safety factor in terms of dimensional clearance to prevent high pressures from a tight necked chamber pinching the case neck, and this means the case neck is blown out on firing and the new projectile drops straight in.

Growth in case length is different, and cases should be measured and trimmed if needed on each firing.