New H beam rods-best way to measure length?

just got my new H-beam rods and was trying to check the length. I measured the big end diameter, small end diameter, then averaged them, then measured the length from bottom of small end to top of big end and added that measurement to the other and came up with a center to center length.
My 6.760 rods measure at 6.7528" to 6.7548".
Is there a better way, or are my new rods not up to snuff. I'm a bit concerned about the .002 difference than I am about them being short. And why are after market rods already .008" shorter than stock?
Thanks, Brian

Well if you can measure it to the 4th point, the way you
did it would be fine... as to why they're short...
that would be a manufacturing problem. You could make
up a checking fiture but it probably wouldnt be much
better... if any

I am also mildly anoyed that the big end width is 1.007". My old stock LY rods with a bazillion passes are thicker.

Dial caliper ?
That will get you pretty doggone close.
Tape measure ?
I could see being of by a couple thou.
That is how I measure them ......... or a couple different snap gauges and a dial caliper if I'm feeling saucy !

Dial caliper. No way for me to check/verify them at 5", but I did check them at 1" with micrometer.