the OAL listed in the manuals isn't absolute?
no, and usually not even close, unless you have a custom rifle w/ specific chamber dimensions you spec'd out before the rifle was chambered.
as w/ most things in life, there are almost no absolutes in reloading.
how do i find the maxium length i can use, just make them as long as i can so they'll still chamber? or is there a way to measure it.
well, yeah, there is a way to measure it, but i don't use it (stoney point tools - go to cabela's website and look 'em up if you are curious about it). the way i find the max length (the connotation there is sorta misleading, but, whatever...): take a deprimed, sized case and seat a bullet very, very long - maybe just have a 1/16" in the mouth. then, take this case w/ bullet ('member, no powder/primer) and use the bolt to slam it home. sometimes you can get the bolt closed, sometimes not. now, take this dummy out, and put it back into your press, and screw the seater stem down to match the new seating depth, and add just a little more - like a 1/16 or 1/8 turn on the stem. take the dummy back out, and slam it home again. you should be able to get the bolt closed this time, though it will probably be difficult. now, do the seating stem operation again. this time, before you jam the bullet into the rifling again, go over the ogive w/ some steel wool to eliminate the rifling marks that are on it. now, slam 'er home again, and using a fairly bright overhead light, look for rifling marks on the bullet. they will be there, but now you can see them very easily. once more thru the seater process and you should have it - if not, repeat the process again. once you know what you are doing, it will take you about 3 minutes to find
your rifle's max c.o.l..
now, before going on, make sure the dummy will fit your mag box. this is an extremely important step, and very easy to skip. don't skip it! if everything is kosher, write the spec's on the case w/ a sharpie and toss it into your die box (eg: rem 700 162 hornady btsp) so you now have a reference point to go back to when you start experimenting w/ seating depths and different bullets, and alter your die's settings.
next step is to load a magazine w/ your new load (these can be live). make sure that the rifle will feed and extract loaded rounds w/o a hiccup. if your bullet is a little too long and is engaging the rifling, you will want to shorten it because eventually on a hunt, you will unload the gun, the bullet will stay, and you will have a disabled gun that needs all the spilled powder cleaned out of the trigger group etc (speaking from experience).
if you have a tru crf rifle (mauser 98), the best way to do this is to pull the bolt, clip the case into the claw, and slam it in... a more tedious process, but it will work.
as far as loading into the rifling... i do it frequently. sometimes just for experimentation, sometimes for a dedicated target gun (where the round that goes into the chamber will always be fired). i am aware of all the warnings about it, and you should be too. if you decide to engage the rifling, then make sure you treat the process as an entirely new load development process, and don't just start w/ your previous best load charge.
also some of my lighter loads the bullets are alot shorter. is there a minimum length they need to be seated into the case?
yeah, they have to be seated deep enough to stay in the case. some say that they need to be at least seated a half of the bullet diameter, others say as long as they are deep enough to not be cocked (excessive run-out), and still others say they need to be at least a full bullet diameter into the case (in a 25-06, full diameter would be at least .25" into the case, half is .12"). you'll figure it out thru experimentation.
remember, altering seating depth alters the case volume, which alters pressures. it also alters the distance to the lands & grooves, which will alter any behaviors such as pressure spikes. all that said, as long as you always come up from below, there should be no surprises.
good luck!
