How many times can brass be used and

[Bassfish1952]

2 things typically can prevent a case from chambering, well 3.
1. Case shoulder length too long, this is checked by the datum point, measured as length from the base to mid-way up the shoulder slope.  6Arc 1.183" give or take (from memory). The case during the firing process stretches out to the chamber forward "shoulder" stop.  Resizing is to bump that shoulder back down until it fits again in your chamber, this is the "bump" that you want to do as ~0.003 or 4 for a gas gun. Some bolt actions, and I say some, might not need that bump b/c during the firing process the shoulder does not elongate beyond the chamber "shoulder."  This feature is usually the culprit when a re-used case will not chamber - the datum length is too long to fit.  Try to jam it and you get a crumpled shoulder.  I have my resizing die set that all my brass fits in all my guns of that caliber.  I'm not in the mood to mess with one set of cases for one gun.  If a chamber is way too long (and I've had those) I usually get rid of that barrel.  Might be ok for some but I don't want that in my setups.
2. Overall length of the case is too long, 6Arc Saami 1.490" max.  There is a slight stop beyond the Saami max where there is a lip that will prevent an untrimmed case (that's too long) from chambering. The case mouth bumps up against this lip when case is beyond length max.  This is the one you're finding now, that trimming will fix.
3. The third one is a case whose walls are too fat to fit, usually from a too-hot of a load fired in one gun (looser chamber) that now will not fit in another's chamber... Re-sizing also fixes this, but this one doesn't happen as often as the other 2.  If this one is happening,  your loads are too hot and you ought to back down in powder.  Or that chamber is too wide out of spec...

Ok so if I only have one gun in 6arc (a bolt gun) once I resize 6.5 Grendel and fire it once or I fire a factory load if reusing in the same gun I should be able to just Trim the neck a little from necking down. 
What the heck I will have the die in a few days and see what it does I will check and make sure it fits before loading 


Thanks Guys