How can I determine/quantify the presence of boron nitride on a metal surface? We use micron-grade hexagonal boron nitride (hBN) to coat the surface of bullets that are jacketed in gilding metal.  This coating is mechanically embedded/plated onto the surface in order to increase the lubricity of the bullets as they are propelled down the rifled bore of a gun.

We can capture fired bullets in a water tank.  There is some question as to whether any of the hBN survives the temperature, pressure, and friction involved in shooting the bullet through a firearm.

How can we determine whether the hBN coating survives the firing process?  Or better yet, can we characterize the quantity that remains on the bullet, or any part of it, after firing and recovery?

Destructive methods of analysis are fine.
I'd suggest looking into the following:
scanning electron microscopy (should be able to see the film and how intact it is on the surface); Inductively Coupled Plasma tests (destructive).  I believe after your sample is prepared and presented ICP can find B and N emission lines