Mathew what chambers are you asking about. Most shotgun
smiths have reamers to deepen chambers. I have reamers
folks can use for my 585,700 wildcats.
Comparing brass cases.I tell everybody who are stepping
up in power from 3.5 plastic, you can get 3.5" brass cases
from Rocky Mtn Cartridge. Here you can see how heavy
and nice they are compared to regular brass cases.
They also make shorter 3" brass cases also.
They fit the chamber tight and are long enough to
get some serious thumping power.And they have a
super strong, thick , solid head, not a weak balloon head
like regular ones on the left in pic.Ed