AR-15 Magazine Length

Recently I went shooting with a friend who is an Appleseed instructor and he was showing me the prone position they teach.  It is very stable position that involves getting your support arm directly under the rifle.  This was a position I was unable to completely achieve with the rifle I brought.

I have short arms for my size.  They aren't quite Tyrannosaurus arms, but they are an inch or two shy of average.  This coupled with the fact I was shooting an AR-15 with a 30 round magazine meant I couldn't get my elbow in a position directly beneath the rifle.  The magazine protruded far enough down that it was in the way.

The standard capacity magazine for the AR-15 is 30 rounds.  There are magazines that hold more and magazines that hold less, but the bulk of magazines in the market today are 30 rounders.  There was a time that 20 round magazines were more common, but even they tend to be a niche product today.

In an attempt to help, I drug out all the different magazines I've collected over the years and measured them.  By looking at them, you may be better able to select a magazine that best fits you for shooting prone, or even from a bench.  I've round 30 rounders can be in the way when shooting from a bench as well.  Anyway, here are the measurements.

Manufacturer	Model	Capacity	Length
C-Products	Aluminum	30 round	7.25”
Magpul	P-Mag	30 round	7.5”
C-Products	Aluminum	20 round	5.25”
Lancer	L5	20 round	5.5”
Unknown	Steel, straight	20 round	5.25”
Master Moulder	Plastic, straight	20 round	4.75”
Bushmaster	Aluminum, straight	10 round	4.5”
C-Products	Aluminum, straight	10 round	3.5”
C-Products	Aluminum, straight	5 round	3.5”
Unknown	Aluminum, straight	5 round	3”
Kel-Tec	Plastic, straight	5 round	2.75”

 Notice the plastic mags in general are about a quarter inch longer than metal magazines of a given capacity.  Also notice that the C-Products 5 and 10 round magazines are the same length, as they use the same magazine body for both.  Lastly, don't take the fact that I measured a Master Moulder mag to think I'm endorsing them.  They are crap, no one should buy them.  I bought 2 for a couple bucks each just to play around with them.  They are as bad as people say.