1. Back in the early late 70's/early 80's that's how I set my resizing die up for .308 and .30-06. Just keep slowly turning the resizing die down till the empty case will smoothly chamber, then turn just a little bit more.
2. I don't throw my brass out till it cracks at the neck. I know I have more than 3 reloadings on most of it. And when it cracks at the neck it gets shortened/resized/trimmed into .300 Black Out brass.
3. Not sure about your bren but with AR15's, M1A's etc. they recommend you remove the ejector and extractor when using a headspace gauge to check your headspace with the gauges.
4. I've almost always found the most accurate load to be 100 to 150 fps slower than the max. load - so it's easier on my brass and my guns anyway. That helps the brass last longer, too.
5. I you don't bump the shoulder back enough, your loads will produce higher pressures, like shooting factory ammo in a gun with a chamber that isn't long enough. I've had pressure issues with a couple AR15's in the past. Very tight (short) chambers. Sort though my other rifles till I find one that's a little sloppy on headspace, swap out the bolts between the "tight" one and the "loose" one and both rifles are happy and the one that was showing pressure issues becomes normal with those loads.
6. Bumping it back too much will shorten the life of the brass (won't be able to use it as many times).
Seems like there was something else but it has "left the building" for now. If I remember it, I'll come back.
