Hello there - this is my first post on what looks like a most useful site. Thank you for having me! I live in the UK and have a question that I would appreciate some help with.
My local target range is limited to 100 yards and I shoot my .308 bolt action rifle there. I have a good supply of UK Radway Green military surplus 7.62 NATO ammunition going back to the 1970s and 80s. I've pulled a few rounds and they seem to be loaded with 43 grains of Nobel No 2 rifle powder. The Nobel manual lists a starting load for 150 grain bullets of 40 grains of No2.
I'd like to reduce the load to reduce wear on my barrel, shoulder and ears. I see no risk in pulling the bullets, dumping the powder and reassembling with 40 grains of powder, but I'd like to drop it further - to, say, 35 grains, or even 30. For economy, I want to use the powder that the round came with.
My question - do I risk detonation?
My understanding of how a cartridge works is that the primer flash envelopes each particle of powder, that then starts to burn at a rate that depends on the chemistry of the powder, its geometry (No2 is a chopped cylindrical powder) and the prevailing temperature and pressure in the case. The difference between a full case and a half full case is that some particles may start to burn later with a full case because the primer flash can't fully envelope them.
But I can't for the life of me see how a half filled case will allow any powder particle to burn instantaneously and cause this detonation phenomenon - I can see that the pressure may even be too low to sustain the combustion of each particle and I'll get unburned powder, but not detonation.
My question - is detonation a myth? Does anyone know of a case of detonation that is not hearsay?
Thank you.