How precise really?

[wnchstrtnfldvlle]

That is about as good as anyone can hold COL.
Measure some of your bullets. Many times they vary. Many times, the meplat or ogive varies, so they hit the seater stem a little different.
First you're loading plated bullets, so accuracy is not a main concern. Secondly, you are almost certainly shooting a gun that will group about 2.5-3" at 25 yes on the best of days. That is something like a 10-12MOA rifle. As such, ANY variation in COL will have no affect on group size, pressure, or any thing else.
I try to control COL as much as I can and I generally can't get the COL that repeatable.
Shoot and stop worrying.

Some one some day has to explain how case length can affect COL since we are talking about the case head and the bullet as the determinators of COL.

Thanks everyone for the advice. I was more worried about the chances of blowing up the gun, versus the accuracy of the ammo. These are my first go at reloading anything, so I figured it never hurts to ask.

 

[ngcsugrad09]

A few thousandths won't really matter, and as others have mentioned, it's most likely from different manufacturers of brass. You'll also find some differences in bullet size as well, but again nothing to worry about.