I usually load Win or Fed brass in a 7 rem mag .I loaded 6 Sako brass as they had similar case capacities as the former and I wasn't running MAX loads. Loaded the Fed necks were .310" dia well the Sako is .315" and won't chamber. I'm not fiddling the neck reaming so I'll pull and insert in Fed brass. All was well within specs for all. Something I hadn't considered before. Don't matter hunting season is over.