Yep. Headspace can be particularly ticklish with 404 due to its gently sloping shoulder. I forgot that I initially loaded with RWS brass that came with my dies. That crap really set me back. For starters the brass overall length was short. When I set my brass up for the short case, it pushed the shoulder back. First indication that something was wrong occurred when I could not get the reloaded cartridges to "snap over" ( = extract loaded cartridges dropped into the chamber). Then primers were jumping out of the pocket. Finally I checked OAL length and discovered cases were short. Then I found a box of new Hornady brass at auction and picked it up for $80 Canadian (about $65 US). All cases were proper OAL. I loaded up a few and no more issues with either snap over or protruding primers. Then I used the new brass to set my dies up to neck size only. Many think neck sizing only is suicide for dangerous game rifles but don't believe it. Just make sure to cycle test every reloaded round and only load brass fired from YOUR gun. If your gun goes haywire on safari and you have to use a camp rifle, do NOT use your neck sized reloads without test cycling them in the loaner first. Anyway, Hornady brass was the fix. I fireformed a few of the RWS cases and reloaded those. Still had problems snapping over. On closer inspection I see the rim thickness on those is very inconsistent. The problem is 404's gently sloping shoulder. It's too easy for a cartridge dropped in the chamber to be pushed ahead too far in the chamber if the extractor can't jump over the rim easily. Not a problem with belted or sharp shouldered cartridges. Who says German components are best? Pfft!
I would NOT put too much faith in Hornady digital scale. My brother had one that was crap. Borrow a balance scale and check it. Personally, I would knock the bullets out of the Hornady factory ammo and start over. Put their powder in the garden. They load 404 way too hot. You'll just get beat up for no good reason. 2200 fps is plenty fast enough for 50-70 yard shots.
Don't be afraid to reuse the new primers pushed out of Hornady cases by your sizing die. Everyone does it and I've yet to hear of a misfire or mishap when loading.
