For some reason we always seem to want to make a hard job out of an easy one, every time this comes up. Look at the 3rd reply, from 2-piper. Using his measurements you can make very inexpensive chamber gauges from stainless steel rulers or any sheet metal wider than the gauge you want to measure. Rulers are nice because the already have the numbers down the side. Using tin snips, a grinder or a sander, narrow the rulers to the dimensions 2-pipes listed. Stick it in and read where it stops. This is the chamber length.
If you have no tools or no mechanical ability, Buy a set. PS, don't grind off the side with the numbers.
