20 VT - neck too small?

[Stretch]

(yes, I'm a beginner) Background: last year I worked up a pretty accurate load for fire forming 221FireBall brass. (I liked the accuracy, but prairie dogs did not..)

So now, after getting "addicted" to the 20VT, and more brass prep, I'm working on a load for the fireformed brass. However, I've noticed that when removing the final loaded round from the press, that there's a very TINY amount of copper at the junction of the neck and the seated bullet. (neck IDs and ODs are chamfered)
Used .226 bushing for sizing (same as I did for working up the fire forming loads).
Is this cause for concern?
(During brass prep, nothing has been done to modify the neck wall thickness - ok, I was hoping to not get involved with "all that"! Stop laughing - i already admitted I'm new to this! It's my first "wildcat".. and I love it! But I'd like some guidence on this, if possible. Thanks!)