With a .224 bullet and brass with .014 necks would you use a .001 or .002 neck tension? Brass is new and I re-anneal after 5 firings so spring back isn't and issue.

.002 is a better way to go. This will help prevent bullet movement from the primer detonation pushing the powder charge forward.

Are you dead sure that 100% of your brass has a uniform neck thickness of zero deviation from .014. If you aren't, then the difference of .001 in your expander, is rendered moot. I assume you are turning your necks to achieve that.
And welcome to the forum.

Right; not talking about pistols with slow powders, nor black powder.
Saeed's results pretty much blows all the heavy neck tension guy's theories out the window. And as for my comments above, you will not notice any difference on ONE thousandth of neck ID, which, on brass, is like measuring jello. Brass does not react like steel, in tension.
Which is why I pay no attention to it as long as the bullet doesn't fall out. Game is killed, the same, in my experience.

Sadly, there are so many misconceptions about loading ammo.

There is no trick we did not try.

Some do work, but most don’t.

Take a little time and try it yourself.

Nothing beats your own results.

I would not consider the difference worth worrying about, and impossible considering the different thickness you have in brass and bullets, even measured..Again the benchrest is where most problems are solved..If you measure all your cases, all your bullets all your varibles, your ready for the men in the white coats from trying to come up with the same answer twice...Reloading isn't Rocket Science by its vary nature..

Trimming cases outside or inside is only for custom cut chambers mostly with zero tolerance..With factory ammo its a waste of time and effort and not a good idea for a number of reasons.