Thanks John, I understand that if the the OAL cartridge length is too long that or if the case head space, base to shoulder is too long that could cause the round to fire out of battery.
My question is how much free bore does a German MG42 7.62 NATO barrel really have? All the reloading manuals say that max case length is 2.015. I have read that military barrels have a lot of free bore, the free space before where the lands and grooves start. I understand that if the OAL cartridge length is too long, that the bullet hitting the lands and groove causes high pressure and a possible OOB.
So, if the shoulder headspace and OAL are good, what we are really talking about is a slightly longer case neck sticking into that free bore area. So, how much does an MG3 barrel have, 2.015, 2.025. 2.035? Am I trimming cases that spec 2.18 for no reason?