Not at all. A flat nose bullet will be shorter than a round nose or a pointed boattail. A solid copper or brass or bronze bullet will be longer than a lead core bullet with the same nose and tail shapes because copper and brass and bronze are all less dense than lead. A tungsten-filled bullet will be shorter because tungsten is more dense than lead.
This article shows pressure among same-weight bullets all loaded with the same powder charge can vary 30% because of the shape and density and hardness differences among the different bullet construction types.
Regarding your particular question about jacketed vs. lead: lead bullets, having softer exteriors, cannot be loaded to pressures as high as jacketed bullet can without some distortion occurring in the base or without lead stripping off the bullets in the barrel, both of which deteriorate gun accuracy. An accumulation of too much lead or copper will raise pressures as subsequent bullets have to squeeze through the constriction that creates. It is always best to look up load data for the particular bullet type you are loading. Get a manual from Hornady or Sierra or any of the other bullet makers and you will normally find the give you the COL they used in testing each individual bullet with the load given. The Lyman manual has both jacketed and lead in multiple weights and is a good source of comparison.
A general rule in handloading is, if you use any component combination that is different from the combination in a published load recipe, you need to reduce the charge weight to 10% below the maximum charge listed and work it up in charge weight increments of not more than 2% of the maximum charge weight listed while watching for
signs of excess pressure. The exceptions are the primer or a change in the particular lot of powder you have purchased, which are changes that normally only merit a 5% reduction. Also, if you got a high-pressure sign during any workup, you stop increasing the loads and you reduce the charge that is giving you the pressure sign by 5%.
If you haven't run into these sorts of rules before, you need to buy and read a good reloading manual or book of reloading practices. The Lyman manuals provide some general information and the ABC's of reloading provides good general instruction on handloading.