Different OAL

[maka]

I am nw to reloading. I have a question regarding OAL.

When you are given a Max. OAL for a cartridge why do people have such different lengths.

I am reloading 9mm for the 1st time and am having trouble finding exactly what OAL I should start at. I have settled on 1.10" with 124g AIM projectiles.

What is the reason to vary OAL?? I realize that some bullets are longer than others but I am pretty sure that most could be loaded to the same length.

 

[RoscoeT]

By varying COL you can get differnt pressures. You can tweak this for accuracy.

Also, the less a bullet needs to jump to reach the lands of your barrel usually the more accurate it will be.

This should be outlined in most decent manuals.

Google is your friend. There are lots of articles on why and how this is approached.

 

[maka]

Thanks, I have just seen a lot of variance people have for the M&P 9mm.

 

[RT]

Also, different bullet profiels ( rn, fp) or even manufacture may feed slightly differently. OAL abit long and the round may not feed, shorten it up abit and it may feed fine. Never shorten the OAL less than the MIN OAL in your reloading manual.