After my sand testing I needed to break down my test mags and clean them out. This gave me the idea to do a comparison of the different types of 1911 mags I have. (All have a good track record for reliability with me. The McCormick is the only one to have had a single failure to feed)

The mags I will be comparing are, (From left to right), Wilson 47D, Kimber KimPro Tac Mag, Chip McCormick (Shooting Star), and Novak (PSI ACT Mag).
All are 8 round capacity .45 acp mags.


There are two modes of disassembly here. The Wilson, Kimber and Novak all have removeable floor plates. Simply depress the retaining plunger with a punch and slide the floor plate off the bottom of the mag. The Wilson and Kimber each have a secondary floor plate that retains the spring as you remove the floor plate which makes disassembly slightly easier. The Novaks secondary plate is free to come out, so be cautious that you don't launch the internals.


The Chip McCormick has a fixed floor plate and disassembly is done by removing the follower by squeezing it and sliding it forward until it is free to come out. (This is not a Power Mag, which would have a similar removeable floor plate like the the others pitured above.)


A comparison of the mag bodies shows that there are significant variations in length, though they all have 8 round capacity. This is where the arguments over longevity and reliability come to play as spring fatigue can become an issue, as demands of the springs are significantly different from design to design. (More on the springs later.) Also, note the Wilson and Novak have curved cutouts at the rear of the feed lips while the Kimber and McCormick have square cuts. Rear seam welds also vary in their smoothness. The Kimber and Novak welds are smooth enough to almost be invisible.


The Wilson mag tube is 4.469 inches in height at the rear and has inward floorplate retaining tabs.
The Kimber is 4.466 inches and also has inward FP retaining tabs. Th Kimber comes with three separate floorplates of different thicknesses for concealed carry and competition.
The McCormick is 4.547. It has a welded floorplate that is drilled for a bumper pad.
The Novak is longest at 4.754 and has outward floor plate retainer tabs.

The thickness of the steel used in the magazine bodies was fairly consistant among the four reviewed here.
Wilson - 0.024" Stainless
Kimber - 0.025" Stainless
CMC - 0.025" Stainless
Novak - 0.024" Polished Blue

Springs were highly varied in design and length. My micrometer wasn't large enough to measure the length of the Wilson and Kimber springs, so I'll just let the picture do the speaking. I'm not sure of construction materials of the springs, so someone else may be able to chime in here. I did measure the diameter of the spring wire of each. You can see the Novak has a unique variable diameter twist to it that is more narrow at the top.
(L to R Wilson, Kimber, McCormick and Novak)


Wire Diameter:
Wilson - 0.045"
Kimber - 0.047"
McCormick - 0.045"
Novak - 0.048"

Followers one of the most significant variations in mag design here.
The Wilson Follower is plastic and is skirted to prevent tipping during feeding of the last round. The Kimber follower is a teflon coated metal follower that also features a partial skirt at the front to prevent tipping. The CMC is one of the simpler designs that is simply folded stainless steel where teh bottom lip engages the slide stop, but it's design does allow tipping. (1911 owners with alloy frames have been known to complain that the stainless steel follower often tips and gets drivven into the frame and can cause some damage to the softer alluminum frame.) The Novak is also a simple stainless follower that has a skirt made by folding the front of the follower downward to also make the slide stop engagement shelf.

(L to R: Wilson, Kimber, CMC, Novak)





That's all I've got for now. Others can feel free to add their thoughts on how these features contribute to reliability.

Also, feel free to disect your mags if you have different ones than those featured here.