Case Expansion and Headspace
Sounds like two different problems appearing to be the same.
All rifles and most handgun cases will expand some when fired. The extractor can usually pull them out (sometimes an overload will 'freeze' them in the chamber) but they are a bit larger than the unfired case. It is NORMAL. That's why reloading dies have a 'resizer'. It is for more than just holding the bullet in place.
Headspace, properly 'excess headspace'. Simplified, this is a condition of the combination of chamber length and bolt face being too long to properly support the case during firing. The case then expands under internal pressure to fill out the space available.
The simplest way to check for excessive (at home, without seeking professional help) is to measure the length of a fired case - from the rifle in question - with an unfired case. If the fired case is appreciably longer, that suggests (not establishes) excess headspace. Another check to examine fired cases for a 'bright ring' around the diameter of the case just above the internal web. This normally shows case stretching, a symptom of excessive headspace.
If convinced or suspicious of excessive headspace, see a gunsmith.
One notes, if the shooter fires only new, store-bought ammunition and does not reload, the condition is an annoyance more than a problem. Headspace problems act cumulatively on cases that are reloaded.
Headspace can also increase with time. With reloaded rounds or increase of headspace over time, the danger is the case will rupture near the base, with the danger of hot gases spewing over the shooter and the front half of the case stuck in the chamber.
Pay attention.