One of my findings dealing with primers is that it is important to have consistent primer depth and crush on seating to have reliable and consistent ignition.
if there is no carbon ring there's a good chance the barrel has sped up as others have sad . Just back the load down to original 3055 fps and check your group size. you have vertical in your groups which means your in upper part of node. If you have stiff bolt, swipes or clickers your over...
One thing to remember is, pressure signs can rear it’s head any time if there is a carbon ring forming or is already formed. Be vigilant with cleaning and invest in a bore scope. To stay ahead of carbon rings.
Check the area where the bolt lugs close over and make they are clean and free of brass filings and powder residue. Brownells sells lug cleaner jags for 2 lug and 3 lug bolts. It’s an area that’s hard to clean and see if it’s an issue. Just a thought!!
One easy way to check to see if you are bumping your brass correctly for your chamber. Is to add a piece of scotch tape( approx. .002) to the case head and insert into chamber. If it close easily your at least .002 off. Keep adding tape till you feel slight resistance that’s how much headspace...
Make sure when you resize that you use the same amount of lube. I use a RCBS lube pad and if it needs more lube than I am applying I get a different bump size and have proven this. So just be aware.
I have had this issue in CA Ridgeline 300 wm. Normally shoot Norma brass with no issues. I was able to get some Lapua brass and it shot fine on first firing , short of full size, chambered fine then loaded and shot with lighter loads and it would not eject. Resized with same dies and would not...