With the number of posts you have, I suspect you already know the following. BUT, Don't let that stop me
There can be a fairly wide swing in velocities when changing from one powder lot to another.
For example, back a few publications of the Speer manual. they listed a velocity in the 300 Winchester Mag. that would be every velocity hounds dream.
Good luck gett'in there! The published velocity was so high, I'd guess there weren't many or even any of rifles that fall into that small group of, "fast" rifles that got there.
Of course, their test rifle/barrel was part of the picture, but very likely the lot of powder they were using played a large part.
I have seen velocities drop by 100fps or more just with the change from lot of powder to the next, and I suspect it goes the other way also.
The question comes up from time to time about the need for a chrongraph, and I'd agree they are not really needed for most of us. I reloaded for years before I had my first one.
However, I sure like having one, and almost all my rifle test loads are fired over the screens at the same time I am targeting them. I really like the additional info supplied.
Then back to my earlier post about the wide swings in velocity that sometimes happens during load development.
In the cases I recall, there were no other signs that my combination of rifle/powder/bullets etc. was not setting well at that charge level. Without the info supplied by the velocity readings, I would have not know it was time to back off and try another powder.
Do I need the chronograph? Maybe not but it will remain part of my program as long as possible.