Now if you want to know the difference in the lengths of the projectile then you will have to do some homework. Different designs and weights will change projectile length. Or you could pull a bullet from each and use a micrometer to measure each. Be careful pulling one from a rimfire as you could easily set it off.
What ever do you mean?
I have three different 22lr's round's, all three have different "cartridge" length's.
Conclusion, not all 22lr's "cartridge's" are the same length.