Personally I have always thought that charging a whole batch of cases in a loading block was just asking for trouble. Just seems way too easy to double charge or miss one. I mount my powder measure to the press with a bracket that goes under the lock ring on the die, and seat a bullet in each case immediately after charging it. Charge case, seat bullet, repeat as required. In 30 off-and-on years of handloading, with over 16,000 rifle & pistol rounds loaded on a single-stage press, I have never repeat never double-charged a case or missed a charge. (yet)
Well boys... there's good news, and there's bad news...
What does a single stage press have to do with careless reloading practices?
Like some others on here I also no longer use loading blocks. My
powder measure is mounted right beside my press. Pick up a case,
charge with powder, look inside, start bullet into case and seat bullet
with press. Hard to make a mistake this way.
That's a perfect solution. Another is to mount UNcharged brass onto the block primer side UP. Then as you charge them, put them back in the block mouth UP.
And no matter how you charge, still check them with a flashlight.
Sgt Lumpy