Re: Headspace gauge
If you continue to just neck size your handloads, they will soon become tight to chamber, and you'll eventually need to FL resize them. This means that your handloads are bulging slightly during the reloading process. You should not be able to "feel" your rounds chamber - not even a little bit.
If your handloads are concentric, they will become anything but concentric after being squeezed into the chamber. Full length resizing is the preferred method of resizing. However, your die height MUST be adjusted accurately. The Digital Headspace Gauge makes this an easy job, and the benefits are not just for benchrest shooters.