Re: 308 win and the berger 215
I like to have one caliber of bearing surface in the neck myself. But for example, the 300 WinMag case only has a .264" neck, and the 300 Savage only has a .221" neck. So I can't be all that important.
Molying bullets is very easy. I simply dump 200 bullets into a vibratory tumbler, add 1/4 teasponn of moly powder, and let it tumble for an hour or two. That's it.
If you go down that road You will want a dedicated tumbler bowl because it will get 'seasoned' with moly too. Or, you can put (fewer) bullets and moly powder in a vitamin bottle, tape it closed, and toss that in the tumbler. Works well, and your tumbler bowl stays clean.
Also, regarding moly, if you are real anal about a clean-to-the-metal bore, moly is not your gig. If you go with moly, the idea is to leave it in the bore. Some folks go hundreds of rounds without cleaning the bore. i usually clean mine now and then, but just a few passes with bronze brush and Montana Extreme solvent, then patch it out. Mainly I'm just removing any excess carbon from the bore.
If you are shooting a good quality hand-lapped barrel, there may not be much point in moly. I use it in my Rem factory bbl's, and a Douglas barrel. For me it eliminates copper fouling, and grants the ability to shoot as many rounds as I want without accuracy going away. In fact mine seem to shoot better good and dirty. You will also be able to eek out a little more speed with moly, but an extra 30 fps at the muzzle doesn't really amount to much at 1000 yards, in drop, drift, or energy.