One tenth of a millimeter might not sound like much, but the larger diameter can cause the bullet to jam in barrels designed for 9mm Luger.
Designed by the famous John Browning, most people will know this cartridge as the. Other names for the cartridge in include the 9mm Short, Corto, Kurz, or 9x17mm. For this reason, the two are not interchangeable. At 23 millimeters in length, this cartridge is not interchangeable with the 9mm Luger. This round has different dimensions all around, including bullet diameter and neck diameter compared to the 9mm Luger. It should load perfectly in any weapon designed for the cartridge.
However, because 9mm NATO is a military round, manufacturers load it to higher pressures. This delivers greater velocity and energy. You may want to make sure your 9mm handgun is rated for higher pressures before you purchase and use 9mm NATO rounds. If you are not an expert, the firearms industry can seem a little intimidating. But when the cartridges are placed along side their peers, the shape of the 9mm Luger's taper becomes obvious by producing a gap between the rounds at the case neck.
The straight-walled 9mm Automatic produces no gap. Taper increases a problematic behavior called nosedive. Nosedive occurs when the nose of the cartridge cams downward while being pushed forward out of the magazine during feeding. This causes the bullet nose to hit low on the feed ramp and at a more perpendicular angle.
A tapered cartridge exacerbates nosedive, and the more a cartridge nosedives, the more likely it will cause a feeding malfunction. Nosedive is an inherent problem in most single stack magazines. Even straight-walled cartridges nosedive, but cartridge taper makes it worse.
Nosedive is less problematic in double column magazines, but it depends on specific magazine designs. Not all 9mm Luger ammunition has the same amount of taper. Taper is defined as case head diameter minus case neck diameter.
Samples of 15 different factory loads in the author's possession had an average taper of 0. The least amount of average taper was 0.
Within any given box of ammunition the amount of taper was relatively consistent. The taper affects cartridge angle when they are stacked together, as shown below. These rounds are not positioned as they would be in most magazines, but it illustrates how the 9mm Luger's taper contributes to cartridge angle. The straight-walled 9mm Automatic doesn't produce this curvature.
The effect of cartridge taper becomes apparent when rounds are loaded in a magazine. When loading a single column magazine, a gap also will eventually appear between the front of the top round and the one under it.
This is called the nosedive gap. As more rounds are added, the nosedive gap gets bigger. The nosedive gap appears with straight-walled cartridges, but the 9mm's taper can increase the gap by about one degree more than a straight-walled cartridge for every round added to the magazine see slideshow. The taper on one side of a 9mm Luger cartridge is about one-half a degree. A larger gap means greater potential nosedive.
Attempts to change some aspect of the magazine or the follower produce limited results. But all these efforts have overlooked the obvious: All that is required for an immediate improvement in feeding reliability is to get rid of the taper, and here is the data to prove it.
I conducted extensive tests with a prototype cartridge that demonstrate clear benefits of creating a new 9mm cartridge with straight walls. The benefits are impressive. A straight-walled case dramatically improves cartridge feed angle and feeding reliability. A prototype straight-walled cartridge was made from. The case wall and rim diameter of the.
The prototype cartridge was made by trimming the Lapua cases to 9mm Luger length of up to 0. When loaded, the prototype cartridge will be referred to as the 9mm Automatic 9mm Auto. In concert with creating this prototype cartridge, functional tests were conducted to assess to what degree cartridge dimensions affect feed angle and feeding reliability. These tests examined cartridge taper and rim width.
I prepared special ammunition for these tests in order to maintain a similar overall length profile. The test ammunition, except for one factory load, was handloaded with Remington grain FMJ round nose bullets to 1. Five different tapers were tested: no taper 9mm Automatic ,. Brand new Remington 9mm Luger brass averaged 0. These cases were not sized prior to loading in order to maintain their original shape of straight, non-parallel sides sized 9mm Luger brass often results in "hour-glass" shaped loaded cartridges.
The profile of the Federal round was very similar to the handloaded cartridges, and was used as an example of factory ammunition. When sized with a. A second group of fired 9mm Automatic cases was partially sized until they had a 0.
Cartridge feed angle was measured from high-speed frames per second video. Feed angle is defined as the lowest angle the cartridge achieves prior to hitting the feed ramp.
The camera recorded cartridge behavior as it was stripped from the magazine. The test gun was a custom-built Caspian single column pistol with a ramped 9mm Luger barrel. Save my name, email, and website in this browser for the next time I comment. View Larger Image. The answer is yes! But, of course, this all begs another important question. Why Does 9mm Have Multiple Names? June 10th, Ammo Insights.
Related Posts. November 10th, 0 Comments. September 22nd, 0 Comments. September 15th, 0 Comments. August 11th, 0 Comments. Frederick Lucia July 30, at pm - Reply. Thank you for the thorough explanation A brand new gun owner.
Mark August 3, at pm - Reply. Ultimately, the difference between 9mm Luger vs. If you want to shoot the same ammo that the troops use for practice and duty thanks Hague Convention , then 9mm NATO is your go to. Load up, and have fun shooting! By Caleb. Aug, 11, Aug.
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