Some ?'s for our AR shooters

[Skinny Shooter]

What ammo have you found to be accurate in your AR?
I was looking at Hornady's TAP and thought I'd give it a try.
That ammo looks like their Vmax bullet.

Anyone with a 1in9 twist? Have you tried bullet weights up to 70grs?

I have a Bushmaster 20" postban with carry handle. Any suggestions on an asking price if I sell it?

Would like a varminter-style gun instead. Doesn't matter if its RRA or Bushie.

Maybe I should keep it and buy a new varmint upper, new trigger and some other mods and install them myself.

Should I be concerned with upper to lower fit if I buy an upper?

Some guns are tight, some wiggle a bit. Does that really affect accuracy? The Bushmaster Predator and Varminter are both tight guns as they come from the factory.

thanks,
Allen