False high pressure signs from oversized chamber?

[NYDAN]

A week or two ago I thought I read a post that said that sometimes a shooter can observe false high pressure signs from an oversized chamber. That comment piqued my interest. Could someone explain that concept further? Thank you. Dan

 

[Ridgerunner665]

There are several things that will give false pressure signs...

Oily chamber (bolt thrust), excessive headspace (brass stretching, which sometimes looks like bolt thrust), etc...

I haven't been awake long...needs some caffeine before I attempt further discussion, lol.