The 30-30 Win Cartridge is probably the most dangerous one to misplace.
Here is a K-98 action Parker-Hale in .270Win that had a 30-30Win chambered by accident!
Years back I would put more than one cal. in my reload box of 100 and was shooting with my then 13YO daughter. She was shooting a .257Roberts and i was shooting a 30-30 and we were both taking cartridges out of the same box. She had 3 rows and then took one out of the wrong row. luckily, the bolt didn't close but i sure did learn a lesson just thinking what could have happened if it was my .270Win she or anyone else was shooting!
And mistakes will always be made,we only lessen the odds by double and triple checking everything we do.
a couple weeks ago i was resizeing .270 brass and after i took a few back upstairs to run them through one of my .270's, the very first one didn't chamber!
I had resized a 20 lot of .280Rem in with the 100 .270's cases!
I have to get a new eye glass prescription!!!
One of the possible contributing factors and this can happen to all of us.
I had a number of years ago tossed all my yellow brass into a storage bin and bought a couple batches of nickle brass for my .270's and now i have given one of the .270's to a grandson and i keep the nickle brass for me and took out the yellow for an upcoming shoot. I checked the boxes of .270 and found where I had over-written the .270 with .280 and it was faded out.
I did resize the .280 back but they are not reloaded at this time.
And I was going to keep this one under my hat.