trazman,
I don't know what's available to you steadily in Slovenia. I would buy sample lots of the brands available to you, cut them to length and do measurements (CCs water, case weight, etc...) to cull each brand. See which are most uniform and start there. It's worth the extra expense to do this instead of wondering: 'I wonder if the brand X would improve my results...'
And then there's powder... and then primers... and then projectiles...
You get my drift.
Cheers,
Phil aka tazzman