6.5 LAPUA CReedmoor Brass Primer?

Also interested to know, I am having issues with mine and I think powder is building up in the throat causing eventual struggle with chambering a round. The bullet has scrapes on it by the neck, presumably from being pushed into the top of the throat wall from the powder. Currently trying to get the issue to happen with factory rounds, from there I'll be trying different powders and primers (assuming I can't reproduce the issue with factory ammo)
 
At least in 2015, the top choice amongst the PRS crowd seemed to be the CCI #450 Small Rifle Magnum primer... http://precisionrifleblog.com/2015/12/27/best-bullets-brass-primers-powder/ - with a smattering of other options. I haven't settled on a primer, yet - I have #450s, #400s, and Federal Small Rifle primers onhand. Going to start with the 450s, though...

_Raining - are you sure you're not seating into the lands?
 
davere. The rounds that wouldn't chamber when the issue presents itself will chamber fine after a quick cleaning. The scraping when forced in is just past the neck to bullet transition. When the issue presents itself I can't chamber factory rounds either.