Many of us BARS did not prime our rockets on our first round of rocketry back in the 60's, 70's etc. I never noticed any paint flaking off or other problems that I would associate with not using primer.
My understanding is that the main purpose of primer is to help paint adhere to surfaces...
I was thinking of planning some testing for an igniter design but wanted some feedback about my idea first.
I was watching slow motion YouTube videos when I came across a couple slo-mo clips of a shotgun primer going off,
Watch starting at 1:58 m,
Watch starting at 5:00 m,