Onmilo, some of what you posted, based on your experience is correct. 1-9" will work well for bullets up to 69 Gr (and even lower than 50, 40's for example).
But there were a few myths, as DTOM indicated.
- Faster twist will NOT cause more barrel wear, or it least the twist will play an insignificant role. The majority of wear is from the gas cutting in the throat, and/or our cleaning efforts without bore guides. (With respect to the other point, by another poster, 1:7 WILL let you shoot the <50 Gr bullets, and often well. The thinner jacketed bullets may come apart if you push them too fast though.)
-Twist and lethality: Speed and bullet shape (which impacts the necessary twist) come into play. The ammo oracle will cover this better than I, and the link was already posted. But with respect to the 55 Gr bullets, the faster twist might just result in a bit slower velocity in that fast twist barrel, and that might be all you have working to make that point.
- Bullets as drills, I don't think you'll find any reference to support that.
But I do think you can find other references, besides myself and DTOM, to dispel the points I questioned.
We all file away what we hear as truth, and for a while, I was SURE there was a Santa Claus. We should all question the validity of what we hear, against what is reasonable. Including my posts. DTOM was probably just trying to discourage the spreading of myths.
He might have fell for that Santa Claus thing too!