Hi, these have been accumulating in my brain for a while now and I thought it would be easier if I just asked all of them in one post, since they are related and follow a common theme. Any information on them would be much appreciated.

1. What is the current gold standard for best civilian-legal defensive ammo? Last I checked, Doc was saying that the Black Hills reinforced 50 gr TSX was the cream of the crop. Has this theory changed at all?

2. Which AR-15 compatible bullet has the shortest ballistic wound neck? The best that I have seen tested is the Sierra 77 TMK, which started fragmenting almost instantaneously in gel. This seemed to be one of the major grievances of M855, so I'm just curious how much the science has developed since its introduction.

3. Has the military stopped using "Brown Tip" ammunition, which was rumored to be 70 TSX loads? When would a round like this be preferred over M855A1 or Mk262?

4. What is the lowest expansion velocity threshold for any bullet that's compatible with the AR-15? I remember seeing a Lehigh .300 BLK all-copper round that they claimed broke apart down to 1400 FPS. 70 TSX apparently goes down to 1800 FPS. Is that about as good as it gets?

5. In a combat situation, what is the most optimal 5.56 barrel length for an unknown theater? I know that John Noveske claimed that 12.5" was the most optimal, and the military seems to be happy with 14.5" after all these years. I would think that as short as you could get while still utilizing a midlength gas system would probably cover your bases for most situations. How often are infantry engaging the enemy at extended ranges anymore?

That's it for now, thanks in advance