Comparing the Manufacturing Consistency of Defensive Handgun Ammunition

By , in Guns on .

Ammunition selection is frequently cited as a critical element in preparation for concealed carry and home defense. The commercial market in the United States provides an enormous number of potential options for any given caliber that differ in terms of manufacturer, bullet material and construction, case material, case treatment, primer construction, powder type and weight, and price.

These construction differences lead to performance differences, as a round may typically over-penetrate tissue, under-penetrate tissue, perform better against targets wearing thick clothing, function better in certain firearms, or better penetrate intermediate barriers. For these reasons, choosing the correct round for an individual’s personal situation can be non-trivial.

The United States firearms community is generally active and information-seeking. One truism frequently repeated on firearms message boards is that the ammunition selected should be reliable in the user’s firearm, and this is often accompanied by the recommendation that the user test fire n rounds through his or her firearm before committing to carry the round in a defensive firearm. Therefore, in addition to the performance differences between ammunition types described above, an individual buyer is also faced with a value prospect.

The more rounds you can test, the better you will understand how they perform in your defensive firearm. However, the number of rounds you can test for a given cost relates negatively to the cost per round. Generally, higher quality ammunition is expected to command a higher price. But, what does your investment actually buy you?

While some of the cost of ammunition is driven by the cost of the raw materials, the remainder may be explained by research and development on bullet construction and, perhaps most critically, manufacturing consistency and quality control. The specific wounding characteristics of different ammunition types is generally well-documented and freely available on the internet, as are the dollar values of the raw materials.

The present study set out to answer a different question: what does your money buy you in terms of manufacturing consistency? To answer this question, we compared the manufacturing consistency between two types of ammunition: Prvi Partizan, a relatively inexpensive option for carry ammunition manufactured in Serbia, and Hornady, a high-end option used by law enforcement agencies throughout the US. The ammunition used was graciously furnished by Widener’s Reloading and Shooting Supply for the purposes of this test.

Methods

We selected Prvi Partizan’s standard 115 grain JHP round to serve as a manufacturing baseline in this study. Prvi Partizan’s factory ammunition is generally regarded as high quality, and represents a standard for what we would recommend for concealed carry or home defense. At the time of this writing, 50 rounds of this ammunition cost $15.99 USD.

We compared the Prvi Partizan round against Hornady’s 124 grain XTP (JHP) Custom load. The Custom load is advertised by Hornady as hand-inspected, and promises hand-loaded performance in a factory load. Note that 124 grain XTP was chosen since, to our knowledge, the 115 grain Custom load has since been discontinued. At the time of this writing, a 25-round box of this ammunition cost $18.85, making it over double the price of the Prvi Partizan ammunition.

Manufacturing consistency in the present study was operationalized as the variance (in standard deviations) in each ammunition’s component dimensions and weights, as well as the velocity of the rounds fired through a chronograph using a Glock 19 with a 4” OEM barrel. The specific measurements taken include,

  • Overall length (OAL)
  • Bullet diameter
  • Bullet length
  • Case length
  • ‘Hole Width’ (of the hollowpoint bullet)
  • Case Depth Remaining (OAL – bullet length, a substitute for seating depth to account for differences in bullet construction between the two rounds)
  • Case weight
  • Bullet weight
  • Powder weight

Note that this is not a test of each manufacturer’s bullet construction – the goal here is to test manufacturing consistency, not effectiveness against a target.

Apparatus

An RCBS Pow’r Pull impact bullet puller was used to separate the ammunition components. The puller was cleaned in between disassembly cycles and prior to testing. A Dillon Precision ‘Eliminator’ scale was used to weigh the ammunition components. General Tools digital calipers were used to measure the ammunition component dimensions. For chronograph testing, rounds were fired through a Shooting Chrony M-1 chronograph positioned 10’ in front of the muzzle, consistent with manufacturer testing protocols.

Procedure

20 rounds were selected from each of the ammunition boxes. 10 were disassembled, and their components measured and weighed. The other 10 were fired through the chronograph to test the velocity.

Results

The results of the study (shown in Table 1) show that the Prvi Partizan ammunition was less consistent than the Hornady in all of the dimensions measured, with the exception of case weight (see Figure 1, below). In addition to the case dimensions, the velocity readings of the Hornady ammunition were more consistent than those produced by the Prvi Partizan ammunition (see Figure 2, below). The sample size was relatively small compared to the n usually required for statistical tests, but nevertheless we employed Levene’s Test (using a median center) to test for equality of variances between the two distributions (i.e., ammunition types).

This analysis tests the hypothesis that the variance between the two ammunition types is unequal and, from the plots, it is easy to see which ammunition type showed more variance. The only difference in variance that was statistically significant was in the Hole Width (i.e., the diameter of the hollow point hole), with bullet weight, length, and diameter trending toward significant. The greatest variance in both ammunition types was in the case weight, with each being +/- roughly 2 grains.

Table 1. Measured dimensions by ammunition type.

 

Figure 1. Variance (standard deviations) by measured dimension for each ammunition type.

 

Figure 2. Variance (standard deviations) in velocity for each ammunition type.

It is worth noting that the Hornady ammunition was much more difficult to separate into components using the bullet puller – each round took roughly 5 impacts to separate versus the Prvi Partizan which generally took only one or two. We were curious to see if this translated into any kind of functional difference, especially given that many people re-chamber the same round repeatedly in a carry gun when they unload it for a range trip or storage then reload it for carry.

To test this (anecdotally), we pulled one round of each ammunition type from the box and cycled it through the test pistol 100 times, measuring the OAL before and after. Curiously, the Hornady round showed a fair bit of setback (reduced OAL) whereas the Prvi Partizan round did not change at all. Obviously this is just anecdotal evidence with a sample size of one, but it should give peace of mind to people who need to repeatedly unchamber and rechamber the same round.

Finally, we also noticed that the powder used in the Hornady ammunition was notably cleaner. The picture below shows what looks to be a wood chip in the first round of Prvi Partizan we opened. While we do not attempt to draw any conclusion for this anecdotal evidence, and to be fair all of the rounds fired just fine, we thought it was important to document every aspect of manufacturing consistency in this test.

Discussion

So what does this mean for actual performance? We considered this question in terms of (1) velocity, (2) expansion, and (3) reliability. In terms of velocity, the bullet and powder weights, as well as the case depth remaining, were more consistent with the Hornady ammunition, and these were likely responsible for the more consistent velocity readings. The width of the bullet’s hollow point was more consistent in the Hornady ammunition, which might ultimately produce more consistent expansion characteristics. Finally, overall case and bullet dimensions were more consistent in the Hornady ammunition, which could result in more reliable operation.

In summary, in addition to materials and bullet construction, money spent on defensive ammunition does appear to buy you something in terms of manufacturing consistency. In some cases, we would expect that these differences would translate to different consistency in terminal performance. Other specific applications requiring consistency include tuning a round to a suppressor (the more consistent the velocity, the closer to the sound barrier you can get without worrying about a round going supersonic). Whether or not this consistency is critical for your use, and warrants the hefty price tag, is a matter of personal debate.

And, it is important to note that even in the extreme cases, the range of each measurement was typically on the order of tenths of a grain, with the exceptions being bullet weight (max range was 1 grain) and case weight (max range was less than 2 grains). That said, we believe that bullet construction and velocity play a larger role in terminal performance than manufacturing consistency, and think that should be the driving factor in defensive ammunition selection.

Editor’s note: the FMShooter team would like to thank Widener’s Reloading and Shooting Supply for furnishing the ammunition used in this review.  We are often asked, “what is the best place to buy ammo?”  After reviewing the prices and selection available on Widener’s, we will certainly be adding them to the list of outlets we recommend for ammunition purchasing.  

Full disclosure – Widener’s has paid FMShooter nothing for this review and/or the above statement, aside from furnishing test ammunition.