a pellet or slug will generate heat has it is pushed down the barrel I dont no how much but with any friction there will be heat
lets be real, OK, the pellet going down the barrel does NOT produce enough heat to cause dieseling ie: self combustion
each oil has a flash point rated in degrees of temperature not in psi or bars,, check the msds, safety data sheets for flash points
rapid compression will create a rise in temperature that dissipates when the compression stops but the pressure remains steady
when I first got my HW50 springer I tried some pellets out, that, BANG, dieseled, I realized that they were lubed with FP-10, then I tried some lubed with my Coltri compressor oil and no bang,, the FP-10 is a hydro carbon based synthetic while the compressor oil was a di-ester based oil, they have different flash points
nothing I have lubed my pellets with to date have caused a dieseling in my PCPs,
your pellet going down the barrel , creating heat is an unsubstantiated worry.