Although my son is partial to the P-Mags, I only use the GI 30 rounders. The speedloader/stripper clip factor is high on my list of “must haves” when storing ammo, so that is also a big reason. I am also quite happy when something associated with a gun is either wood or some sort of metal – it just makes me happy……
I like the reference to the 20 rounders fitting in a back pocket. That is quite true and usually forgotten, so good point. The cheap Condor chest rigs are just so simple and easy to use that I have long since foregone pocket carry of magazines if I can help it, though. There are even some nicer 3 mag rigs that fit nicely under a coat if you don’t want everyone thinking you are Mr. Tacticool Guy.
As far as the available room for reloads, I have had this argument with my brother on several occasions. He has gotten into the habit of using the ID of his mags for the OAL of his loads no matter what bullet….. Yeah, don’t start – I know and have told him how stupid that is and he should use book specs…. /sigh