Keep the brassseparate for each gun. It might become necessary to completely full-length resize the cases each time they are fired in the semi-auto, but you will be able to use partially-resized cases in the bolt-action as long as they are ONLY fired in that rifle to begin with. This means your semoi-autocases are NOT going to last as long as the ones you use in the bolt action only. But this difference is to be expected.

IF you clean your brass well before running it into the resizing die, it really isn't necessary to clean out the die, as long you don't get anything into the die except case lube. I suppose there will be an accumulation of small brass flecks over time and wiping that out of the die won't hurt anything. I've never done this, however,and have never experienced any problems I could ascribe to not cleaning out the sizing die. However, when seating lubricated lead bullets, I HAVE had bullet lube buildup in the SEATING DIE to the point that I had to remove the seating stem and clean all the bullet lube out of the die before I could finish seating the bullets!!

Yes, it is possible to "over-chamfer" the case mouths after trimming. You cdon't have to make the case mouths sharp enough to shave with!! I only twist my chamfering tool three or four complete revolutions in the case mouth, deburring and putting a very slight bevel on. A couple of twists with the other enddeburs the outside edge sufficiently-just cut off the "wire edge".

I don't FL size new unfired brass, but it may be necessary with some to run them into the die far enough to make the case mouth round! Sometimes, new cases arrive with the mouths somewhat collapsed.

Yes, a dent in the case neck/shoulder after resizing is an indication of too much case lube. But that's better than not enough, which can result in a case stuck in a sizing die.Then the fun begins!!