There's a science to match chambers that I'm sure someone here can explain a lot better than I. A match chamber is typically a bit tighter and shorter which allows the bullet to engage the rifling when chambered which eliminates jump and maintains consistency.

I'm not sure a match chamber makes a great deal of difference unless you're using ammo and a rifle to 'match'. The advertised Laney chamber on the PC model doesn't seem to be delivering much different results according to what I have read here from PC owners.