Re: brass life ?
My conscience won't let me not really help you.
Check for:
loose primers
bright spots on the case just in front of the case head
split necks
work hardened brass that won't size
case stretching, the brass is coming from somewhere
And most importantly use a pick to "feel" the inside of the case, checking for thinning of the case in the webbing in front of the head where it begins to form the body. If it separates here you're in trouble, so this is paramount. If you aren't sure, start cutting/grinding one of your cases into a cross-section after each reload, so you see the thinning starting to take place. Pitch em early = small amount of lost $, Pitch em late = small amount of lost flesh/life
A few variables that influence the serviceable life of cases:
amount of re-sizing
-sizing method - FL, neck, shoulder bump, etc.
-chamber and die deviation
-skill of handloader
-concentricity of chamber, die, and brass
-forming process
case design
-capacity relative to bore size
-body taper
-shoulder angle
-headspace point
case prep
-annealing
-number of steps that work brass
-chemical cleaning
brass itself
-metallurgy
-quality control
load pressure
prioritization of safety
Some folks claim 50 or more most get much less. There is a bell curve to this topic that directly correlates to a handloaders manipulation of (but not limited to) the above variables. I am guessing from your question that your understanding places you on the left side of the bell. When I started handloading (left side of the bell) my self respecting limit on my 300 RUM (similar case) was 4.
So my guess is 4.