Constructor, how do you chamber your barrels?
What do you mean?
Do you chamber it to min specs?
Those numbers you gave as "typical" of other manufacturers seem pretty sloppy. Do you go any tighter than .422" at the base?
We must chamber the diameters to spec because most reloading dies only size .002" under or .420" The chamber needs to be .422 to keep the cases from sticking.
When the SSA cases expand from .415 to .422 that first time it has a bulge. Not much we can do at this point. I tried in 07 to use a smaller chamber to keep the bulge to a minimum but it required the use of small base dies. The SSA brass swelled from .415 to .420 then were resized to .418. The problem was getting everyone to use the correct dies to keep the case stretch down. After a while I gave up and used the same diameters as everyone else.
When matching bolts to barrels I have a gauge (GO +.003)between the "go" and "no-go" I use to keep the headspace more toward minimum. At least that helps keep case stretch down.
ETA- There are other things that we must consider. There are only 2 companies in the country that grind carbide dies. Every reamer maker has a tolerance of +-.001. If I spec out a reamer .422 it may come .421 or .423. If it cuts a chamber .421 and the resize die maker's die is large and only sizes to .421 the cases may or may not stick in the chamber of a semi. It's not as easy as many think and I'm not making 1 barrel for 1 guy. We're making 10,000 barrels for people I don't know using resize dies made to several different specs.
If I was making something for myself and wanted to use SSA brass I could design a reamer .417 in dia so the brass expands .002 on the first shot then have resize dies made by Whidden that resize back to .415. That would make the brass last much longer.
