Interesting solution, I've always full length sized and have always followed mfg's instructions for setting my sizing die to accomplish this. That is until this year when I experienced some premature case failures, burned a lot of powder and wasted a lot of bullets in a custom 6.5x55 Swede I had built. After borrowing a set of headspace gauges and confirming my smith's claim that he had cut the chamber "tight", I bought the Hornady LNL headspace bushings and discovered that with my sizer set to mfg's specs it bumped shoulders back .014", double the allowed headspace per SAAMI spec. I will allways use this tool now and set my dies to bump .002". I use to be a machinist and you'd think that I'd know better but I'd been loading for many years and had never had a problem (until now) with this practice.
I considered necksizing for while, but after a discussion with a knowledgable friend he convinced me that a full length size with shoulder bump is the way to go. Neck sizing is OK for the bench rest guy where reliable feeding is not imperitive, but not for a hunting rig. A .002" bump only allows for .001" per side when the round is chambered, not a lot of room, but enough to guarantee reliable feeding while not leaving excessive headspace or misallignment of the projectile with the bore.
Nobody, a method to check your chamber to get an idea whether it is tight or not. You'll need a set go/nogo chamber gauges and a micrometer, rentable or borrow from friend or smith. Obviously you're go gauge should chamber easily, if not your chamber is too tight. You're nogo gauge may chamber or not, there is a misconception here because there is a third gauge the "Field" gauge which is the true high end of the allowed tollerance. If the nogo chambers your chamber may still be OK if a Field gauge won't chamber, your rifle will just be hard on brass loaded to factory specs. If you set your die to bump .002" on a Field gauge chamber it won't be any harder on brass than any other rifle. If it doesn't chamber the nogo gauge, your chamber is cut within standard tolerance. Now, you can find out exactly where your chamber is by shimming the back of the go gauge with scotch tape(.0015"-.002" per layer but measure with your mic) or .001 shim stock until it won't chamber, count the total number of shims and multiply by the thickness of your shim stock and add this number to the number etched on the side of your go gauge and the result is your chamber length from bolt face to datum point. My tight chambered 6.5x55 Swede will close on the go gauge with 1 shim but not 2.