nothing is changed: size is different in two successive builds of rpm

[Nagrik]

Hello Group,

I am building same rpm successivley one after the other. Absolutely
nothing changes in two successive builds, except of course the time.

However, the size of two rpms (although nothing changed on the
contents side) is always different.

Can anyone tell me what goes in the build of rpm, and why does the
size is different, although nothing changed as far as the contents are
concerned.

I will appreciate any feedback.

Thanks in anticipation.

nagrik