School me on OAL

[Poppa Bear]

I would like to see a listing of bullet lengths listed as part of a cartridges load data. Loading using Round Nose 115gr bullet X with the same weight as Flat Nose bullet Y and knowing that bullet Y has a length of say .650" makes it real easy to determine a cartridges actual area under the bullet used by the powder charge. This is the part that is MOST critical to reloading. Knowing the bullet length used in the manuals data now gives me the ability to verify my load is still at a safe length.

[1SOW]

re bbl 'drop in test':

Using a spent case from your pistol, by hand seat a bullet enough to not fall out. With the bbl removed, Gently push this into the bbl chamber until it seats firmly on the case mouth. The bullet IS now TOUCHING the lands or cone at this depth. Gently dump/pull the case out and measure this length. Do this several times to get a consistent length.

AT THIS LENGTH THAT brand and nose-type BULLET IS CONTACTING THE LANDS AT THAT OAL. Subtract about .015" and that is the MAX USABLE OAL for THAT type and brand bullet in THAT chamber. Loads at or shorter than this oal will feed in that gun. Every chamber and every different brand and 'nose-shape' bullet will have a different max usable oal.

This test does not give you the powder load or the oal that is best. It just tells you the maximum OAL that can run in that pistol. If load data for that bullet gives an oal "shorter" than the max usable, it will run in your pistol.

A 9mm 124 FMJrn may show 1.20+" is max usable oal, so it can run at 1.169" SAAMI MAX length or shorter with the proper load.

A 9mm 124 JHP may show 1.09" is max usable oal, so as long as your mags will feed it, it's good-to-go with published data at that oal or shorter with the proper load.

Hope this makes sense.

Edited July 29, 2011 by 1SOW

[Steve RA]

One assumes that with the method I outlined the user would be able to recognize a round that was considerably shorter, bullet even with case mouth - for instance, and would not try to use it.

[carbon9]

I am sure everybody already does this as well but didn't see anyone specify... When I am determining length to the lands/rifling, rather then just dropping the round in while listening and looking I spin it while it is in the chamber to see if it is engaging the lands. If it doesn't spin freely you are engaging the lands.