comparator

Now this may be a question that others have had (and I did do a cursory search but did not find a direct answer to the question) so here goes: Is there any correlation between cartridge overall length (as shown in reloading recipes) and comparator length? I recently reloaded some 300 AAC with...

Pushing the shoulder back to far when full length sizing may let the brass stretch to much on firing. Case separations may be the results. Short case life. The fired brass is not always the true length of the chamber. May take 3 firings, neck sized.