Re: Overall length what is too long?
Congrats on getting into it you will have some fun. There are a couple of answers to your question so i hope i don't confuse things. First what are you looking to be able to do? If you want to be able to feed from a magazine you will have to limit the oal to something just under the internal dimensions of the mag. If you don't care about being able to feed from a mag the oal is much less relevant as there is not real outer limit so long as the bullet is held in the case neck. You can play with into the lands touching the lands and off of the lands in various increments till you find what your gun likes. Some mags or calibers it wont make a difference ie you can seat a bullet very long to be able to get you into the lands of your barrel and still be able to feed from your mags other calibers and rifle setups that are mag fed will almost ensure that you will have some level of jump to the lands. I often find most of my best loads are into the lands with Long Range VLD style bullets BUT NOT ALWAYS and i have also found other accuracy nodes that worked with a lot of jump. I know some who shoot short action rounds in a long action just so that they can use the mag. If its a true long range gun you likely arent giving up much having your OAL turn your gun effectively into a single shot due to oal. in LR my opinion is that accuracy and finding the best load is more important than saving a second on the reload. if you're shooting 1000yds and your first hit is off throwing another round downrange without other adjustments is not wise so again a second isn't going to change much.
Sinclair sells a great tool that will show you how to get to the lands touching then take that oal and add or subtract length off of that with your seater die to start experimenting. also to be more precise use a comparator to measure bullet OAL as the tips on many bullets vary enough to make a difference and measuring length off the ogive will give you better and more repeatable results.
Hope this helps as a starting point.
I agree! But here is a way to measure your oal for each bullet.
1. resize a brass Donot prime or powder it but lube the inside of the neck
2. place a bullet on the brass and put into the seat die just enough to hold it and no more
3. pointing in a safe direction chamber it, the bullet will seat itself at the lands, now place it back into the seat die with the seat adjust all the way out and screw it down on the bullet
4. measure this then repeat step 3 and screw it down (a 1/8th turn then measure), until you are down 5 or 10 thou off the grooves
5. place this dummy in with the box of bullets for die setup
when I have loaded the 99th out of the box I pull that dummy and load it.
I do this for every package I buy, all of my loads are 5 thou off lands and this method saves me a lot of time with die setup