This page was first published online 7-26-2008
This page was last updated 5-23-2009

Para Ordnance double column high capacity magazines nicely illustrate the importance of magazine design for feeding reliability. The cartridges are arranged in a staggered array deep in the magazine. But at the top of the magazine the cartridges form a single column aligned with the barrel (Figure 1). Thus, the cartridges deep in the magazine must transition from a staggered double column array to a single column as they move upward under spring pressure. The magazine body forms this transition, but there are also grooves in the magazine body that play a critical role.

Figure 2 shows the four different caliber Para Ordnance magazines. The black lines point to the location of the "transition groove", the groove in the magazine body that assists the cartridges in forming a single column for feeding. The red line illustrates the approximate length of the transition groove. The length of the transition groove is very similar for the 38 Super, 40 S&W and 45 ACP magazines, but the 9mm magazine has a very long transition groove that extends farther down the length of the magazine body. This extended groove in the 9mm magazine means that the cartridges start to form a single column much sooner than in the other-caliber magazines. The transition groove is at the front of the magazine, which could influence the front of the cartridge more than the rear.

Figure 2

Note also that the 9mm, 38 Super and 40 S&W magazines are ribbed, while the 45 ACP magazine is not. The Para Ordnance frame was designed to offer increased capacity for the 45 ACP 1911 type pistol, therefore the width of the magazine had to accommodate the large 45 ACP cartridge. The magazines for the smaller cartridges had to fit in the same frame width, but required less horizontal space in order to stack the cartridges correctly for reliable function, so the magazine walls were ribbed to provide the proper internal width. The ribs are necessarily deeper for the smaller 38 Super and 9mm cartridges than for the larger 40 S&W cartridge.

Nosedive Gap

There is a straightforward relationship between the dimensions of the transition groove and how effectively it facilitates reliable feeding. Ideally, the cartridge would lie at, and be stripped from, the magazine at an angle optimal for reliable feeding.

Nosedive Feed Failure

In a nosedive feed failure, the top round nosedives as it is pushed forward by the slide. The bullet's nose hits lower on the feed ramp and at a sharper angle. This sharper angle can cause the cartridge to stop dead. This can produce significant bullet setback (pushing the bullet deeper into the case) that will increase pressure if the cartridge is chambered and fired. If the load is already at high pressure, more pressure can be dangerous. Nosedive feed failures are exacerbated by flat nose bullets. Flat nose bullets hit lower on the feed ramp than round nose bullets, and some flat nose bullets have a rather sharp corner, which is less friendly to reliable feeding than a round profile.

With only one round in the magazine, the feed angle is usually ideal. But as noted in the overall length section of this website, as more round are loaded in the magazine, the angle of the top round can change. The angle changes because the angle of the cartridges below the top round changes. If the angle of the underlying rounds changes very much, a gap will appear between the top round and the one under it. This occurs when, because the cartridges are offset, the rim of the top round slips into the extractor groove of the underlying round. Due to mechanical forces, as more rounds are added to the magazine, the force of the spring pressure on the top cartridge is focused on the rear of the cartridge where it is pinched between the feed lips and the round directly under it. The gap allows the nose of the cartridge to pivot freely - which is the source of the nosedive. I call the gap the "nosedive gap" (clever, eh?). See the text box for a brief description of the nosedive feed failure. The appearance of the gap is unavoidable in single stack 1911 magazines, but double stack 1911 magazines (and others) are a different animal and they can be designed to completely eliminate the gap. The beautiful thing about Para Ordnance magazines is that they illustrate how simple it is to eliminate the nosedive gap in double stack magazines.

The presence or absence of the nosedive gap in fully loaded Para Ordnance magazines is shown in Figure 3. The 9mm magazine (Figure 3A) and the 40 S&W (Figure 3D) magazines have no nosedive gap when fully loaded. But the others do. Of particular interest are the 38 Super and 9mm magazines. With 9mm ammunition in the 9mm magazine (Figure 3A), there is no nosedive gap. But when 9mm ammunition is loaded in the 38 Super magazine (Figure 3B), there is a big nosedive gap. Thus the simple change of extending the transition groove farther down the length of the 9mm magazine body (compared to the transition groove of 38 Super magazines in Figure 2) was all that was needed to raise the nose of the cartridges immediately under the top round and close the gap.

Before I got my hands on a 9mm Para Ordnance magazine, I used to run 9mms through the 38 Super magazines (Figure 3B). The substantial nosedive gap produced many nosedive feed failures. This was a common problem when I had more than about 10 rounds in the magazine, and after considerable frustration I learned to not load more than 10 rounds of 9mm in order to keep the gun running. When I did get some proper 9mm magazines, the nosedive problems stopped completely.

The 38 Super cartridge also has a nosedive gap when in the fully loaded 38 Super magazine (Figure 3C). But note that the gap is smaller than the gap with 9mm Luger ammunition in the 38 Super magazine (Figure 3B). Do you know why? It's because the 9mm Luger has a tapered case, whereas the 38 Super has a straight-walled case. The tapered case exacerbates the size of the gap. Loading 38 Super magazines with 9X23 Winchester ammunition produces a nosedive gap intermediate between the 9mm Luger and 38 Super. The 9X23 has a tapered case too, like the 9mm Luger, but because it's long like a 38 Super, the overall angle of the taper is less than the 9mm Luger.

Does the 38 Super have nosedive feed failures when loaded in 38 Super Para Ordnance magazines (Figure 3C)? The gap is pretty small, but when fully loaded, and especially when higher capacity (longer) magazines or extended basepads are used, the chance of a nosedive feed failure increases. I had many feeding problems from the Para Ordnance magazines with traditional semi-rimmed 38 Super cases. The semi-rim can cause reliability problems in double column magazines. I use rimless 38 Super cases (Brass) in the Para, and while I might have had some feeding malfunctions when using flat nose bullets in the 38 Super magazines, I don't have a good memory of that happening, so it has not been a chronic problem. I also don't recall having any feeding problems when using round nose bullets and 38 Super magazines. The 38 Super runs pretty reliably with Para's 38 Super magazines (with rimless cases). That said, I now use the 9mm magazines when shooting the 38 Super in the Para Ordnance. The 9mm magazine is the superior design because it has no nosedive gap at all with 9mm Luger, 9X23 Winchester and 38 Super ammunition.

Nosedive feed failures are a problem with Para's 45 ACP (Figure 3E) magazines. My Para 45's run fine with round nose bullets, but often jam with flat nose bullets due specifically to nosedives. Para Ordnance could easily fix their 45 ACP magazines by extending the transition groove father down the magazine wall just like they did with the 9mm magazines. Para Ordnance, are you listening? It would be an easy fix to make the Para Ordnance an ultra-reliable 45 Auto.

Questions, comments, suggestions, hate mail? Feel free to email me. However, the probability of getting a response is low simply because I have a day job and a life and don't have the time to respond to all emails. It's nothing personal, really. Nevertheless, I do appreciate your thoughts. If you see an obvious error then please put the word ERROR in the title of your email. Thanks, and happy shooting.
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