Re: oal for .308
Turret,
I do not believe the loads will explode if you fire them, but I personally would never advise anyone to fire a known "out of spec" load. The issue is you did not load them up yourself. Did your friend use Varget, or H4895, or was it IMR4895, or maybe he had varget on his bench but unique in the hopper. If he mistakes the oal, his credibility is in question.
Reloading is a fun hobby, but it is one that can be less forgiving of mistakes.
SAAMI published standards are for manufactures of ammo, powder and bullet companies publish guidelines based on loads they worked up in labs. Are they absolutes? No
Being new to reloading, it is best to stick to published and credible loads until you have a full understanding of pressure and its effects on brass, chambers and projectiles.
Most guys who are familiar with reloading can look at a load and instantly know if its hot or dangerously under loaded (in case of bottle neck cases and slow powders). For someone knowledgeable in reloading to advise a noob to completely ignore published data is poor mentoring and down right irresponsible.
This hobby is very rewarding, don't start out with bad habits.