Hello this is my first post on this site and I’m hoping someone can lend me their expertise. I recently purchased a Sako TRG 42 in 338 Lapua as a step up over my .308 and have fired 30-40 rounds through it. A mix of Sellier & Bellot and Federal. The rifle itself functions flawlessly and I’m very happy with it. However after looking at my spent brass, I’m noticing a slight bulge in the neck on all the casings. I’ve been searching online for similar problems but can’t find anything helpful. The accuracy is good and everything else appears normal. This is my first 338 Lapua but I haven’t observed this happening on any other caliber I shoot, so it has me a little concerned. Anyone know what’s causing this and if I need to send the rifle in for warranty or is it nothing to worry about?