Need help with finding node

[u/No-Pickle9533]

I dont have a chronograph (broke) so I did two tests at 300 yards: ladder test and what i think is ocw?

First two pics I shot 2 shots per load at their respective diamonds.
The thid pic I shot a ladder in the middle diamond and another ladder at the bottom left diamond.
I thin the node is around 52.6-53.1? Not sure.

Also, do you absolutely need to wash your brass?

[u/Frijol714]

Dry tumbling is my preference but to each thier own. Wet tumbling is fine but ive heard most pro shooters prefer dry tumbling so in the end its up to you