Special

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Handloading

This page was first published online 1-9-13
(Note: On this page, as throughout this website, the term "38 Super" refers to the 38 Super +P cartridge.)

The 38 Super uses small pistol primers. Either standard or magnum can be employed, and this will depend on user preference and gunpowder selection, though few gunpowders used in the 38 Super require magnum primers.  Magnum primers produce more “spark” than their standard cohorts.

Small rifle primers can also be used, as they are the same size (diameter and height) as small pistol primers. They produce even more spark than magnum pistol primers. However, at some forums on the internet there have been claims that using rifle primers with low pressure powder charges in pistol cartridges has resulted in breech face erosion. The cause is purportedly that the rifle primers require more pressure to form a good gas seal, and that low pressure loads allow the hot propellant gases to leak around the primer and erode the breech. Some folks claim they use rifle primers all the time in their pistol ammo and have not experienced any breech face erosion. Other folks claim that this erosion is due to excessive headspace, and this allows the primer to back out of the case far enough to allow gas to escape before the case is pushed back by the pressure to reseat the primer. I can’t verify any of these claims, but it is easy enough to avoid using rifle primers in our pistol ammo unless warranted, such as with excess pressure that is often achieved to make Major power factor for use in competition (see the Major Power Factor page).

Not all primers are created equal. They differ in sensitivity and what level of pressure they will withstand.

Sensitivity

Primer sensitivity refers to how much force the firing pin needs to strike the primer with to set it off. This is seldom an issue for factory built guns since they provide more than adequate firing pin force. Some custom tuned guns will reduce the hammer spring weight to produce a lighter trigger pull. Some competition guns will use very light hammer springs, and primer ignition can be an issue.  Revolvers built for competition have notoriously light hammer springs, and they might not reliably set off all brands of primers. Thus the need to identify how sensitive particular brands are to firing pin force. The reported sensitivity ranking is shown below for the commonly used primers in the U.S.A. This is largely based on posts on various forums and discussions with revolver shooters. Federal small pistol primers are the hands-down favorite of competitors who use tuned revolvers with light hammer springs. They are ranked from most sensitive to least sensitive.

1. Federal

2. Winchester

3. CCI

I’ve not seen a consensus for where Remington primers rank.

Presumably the magnum primers are a little less sensitive than their standard counterparts because of a supposedly thicker cup material, but I have no evidence to say one way or the other. Rifle primer brand sensitivity ranking matches the pistol ranking. Rifle primer cups are thicker than pistol primers because they must withstand higher pressures, and they are less sensitive in general than pistol primers.

The only issues I’ve encountered in a semi-automatic pistol have been using rifle primers and light hammer springs.  I occasionally had misfires with CCI small rifle primers when I used a 17 pound hammer spring along with a titanium firing pin in my 1911. Switching to Federal small rifle primers cured the problem. I’ve never had a problem setting off CCI pistol primers in my semi-automatic pistols.  In fact, my standard pistol primer is CCI, and most of my 1911s have 19 pound hammer springs.

Pressure

Pistol primers are designed to withstand pressures of typical pistol cartridges, around the mid-30,000 psi range, and are more sensitive than rifle primers because pistol firing mechanisms don’t have the same power as rifles. Rifle primers are built for higher pressures that are in the 60,000+ psi range.

There is one obvious outlier with respect to pressure limits. It is the Remington 1 1/2 primer. The following is printed on the Remington box: “Do not use 1 1/2 small pistol primers in high intensity pistol cartridges such as the 357 magnum, 357 SIG and the 40 S&W. Damage to your firearm and/or personal injury may result.” 

What does that mean?  They are not intended for high pressure pistol loads. The pressure “limit” for the Remington 1 1/2 primer is not indicated. Since the 38 Super and 9mm Luger also have pressures in the same range as the above mentioned cartridges, Remington 1 1/2 primers should be used with caution in any loads in these calibers that approach their SAAMI maximum pressure limits. I discovered the limits of the Remington 1 1/2 primer in the 9mm Luger when I experienced pierced primers using some common loads. These same loads had not produced primer issues when using other primer brands.

I was curious whether brands of primers would react the same to pressure, so I ran a test covering a range of pressures with the pistol primers commonly available in the USA. I compared 9 different primers, Standard and Magnum CCI, Federal, Winchester and Remington, and I included a Federal small rifle primer for comparison. Loads were tested with the 9mm Luger with Winchester 231 and 124 grain Winchester FMJ bullets loaded to 1.155" OAL. Brass was virgin Starline 9mm Luger. The gun was a 5" Para Ordnance. Temperature was approximately 50˚F. Ten rounds were prepared for each load.  All rounds were fired over a chronograph to measure velocity.

The charge weights ranged from standard pressure to excess pressure. The excess pressure loads were included to stress the primers beyond the range of typical pistol pressures to determine if some primers would hold up better to excess pressure than others. I knew from experience that I had a margin of safety with my test pistol. The Para Ordnance barrel has a fully supported chamber, which is a requirement for any excess pressure loads (see the Major Power Factor page). Additionally, I run 9 Major loads through this same pistol and estimates of pressure from those loads likely equal or exceed the estimated pressure of the loads for this test.

I used Winchester 231 for this test. This is NOT an endorsement to use this gunpowder for excess pressure loads. Remember, this was an experiment by a shooter with considerable experience with the gun, the gunpowder, and excess pressure loads. Extreme caution was employed in carrying out this test.  As progressively higher gunpowder charges were tested, the brass and primers were examined very closely to determine if pressure signs were considered dangerous.  I fully realize that these methods are imperfect, and that there are risks involved with any undertaking of this type. If I had seen at any point that the ammunition was showing dangerous pressure signs I would have stopped immediately.

DO NOT try to repeat this experiment. You might get much higher pressures, which could lead to catastrophic failure and injury to the shooter and damage to the firearm.  The experiment has been done. Look the data over and use it for reference when selecting primers.

Please keep in mind that strictly speaking, my results can only be applied to the specific lot numbers of the primers (and gunpowder) I used (and only apply to my pistol). Presumably there are relatively consistent standards in primer manufacturing, but minor differences between lot numbers can skew the results in either direction. Hence, these results should be viewed as one example of a comparative outcome and not as a definitive comparison per se.

Maximum published charge weight for 231 and a 124 grain bullet for the 9mm Luger in my resources is 4.5 grains. My starting load was 3.9 grains of 231. This was below the listing in my resource so I don’t know what the pressure is, but using linear interpolation it would be around 24,900 psi. I started with this load thinking that it might show pressure signs in the Remington 1 1/2 primer. In fact, I only loaded this low charge for the standard primers. The next charge weight was with 4.2 grains of 231. The pressure for this load according to the Winchester 15th edition Reloaders Manual is 28,800 psi (in their test gun). Their maximum listed load was 4.5 grains, producing 32,700 psi. (The maximum SAAMI limit for the 9mm Luger is 35,000 psi. The +P pressure limit is 38,500 psi.)  I estimated the pressure of the largest load I tested (5.4 grains) to be around 45,000 psi using linear interpolation. I realize that pressure might not follow a linear function but this was the only method of estimation available to me without further information.

Fired primers were graded for the amount of deformation, which is shown in the Pressure Signs table. Primers were compared directly to unfired primers, as they appeared in primed brass. The scale starts at “okay” indicating no obvious change in the primer, meaning no clear evidence of flattening or cratering. At the far end of the scale, “extreme” would indicate a pierced primer. I recognize that the process is subjective and you’ll have to rely on my judgment, but I did attempt to be as objective as possible.  I noted that the Remington primers tended to show cratering as a dominant feature, whereas the other brands tended to show flattening as a dominant feature.

Powder charge weights with red color exceed the recommended maximum charge weight and estimated pressure established by SAAMI for the 9mm Luger cartridge.

I did not load high charge weights with the Remington 1 1/2 primer.  Based on previous experience I expected higher pressure signs than I saw with these charge weights, and expected pierced primers with the 4.5 or 4.8 grain load. However, much to my surprise, I did not have any pierced primers at all. In any event, this primer did not tolerate the higher charge weights very well, and it did react more severely to pressure than the other primers.

Not all primers from a group of 10 shots looked the same, though some did, and the ranking reflects the highest rank seen among the 10 shots. The Percent table indicates how many of the 10 shots showed the highest ranking pressure assigned. With some exceptions, there was a reasonable progression of pressure signs as the gunpowder charge increased. The CCI magnum primers tended to show more deformation than the standard primers. The Federal small rifle primer did not show any clear signs of deformation with these loads.

Powder charge weights with red color exceed the recommended maximum charge weight and estimated pressure established by SAAMI for the 9mm Luger cartridge.

Velocity

The velocities are also shown. Velocity changes were linear over the range of charge weights tested. The slight bump at 4.5 grains could have been due to measurement/scale/machine error. The extreme spread of velocities of all the primers at a given powder charge was quite small achieving a maximum of 29 fps.

Powder charge weights with red color exceed the recommended maximum charge weight and estimated pressure established by SAAMI for the 9mm Luger cartridge.

We often predict that magnum primers will produce more velocity than standard primers because of their greater spark.  My results showed some velocity increase with magnum primers compared with their standard counterpart, except for the Federal primers, which were about equal. Still, the velocity gain with the other magnum primers was pretty small. Note also that the Federal rifle primer did not produce velocities greater than those produced by the pistol primers.

Powder charge weights with red color exceed the recommended maximum charge weight and estimated pressure established by SAAMI for the 9mm Luger cartridge.

STANDARD DISCLAIMER: My results are specific to my test conditions (components, gun, environment). Your results might be different.

References:

ANSI/SAAMI booklet Z299.3-1993. American National Standard. Voluntary Industry Performance Standards for Pressure and Velocity of Centerfire Pistol and Revolver Ammunition for the Use of Commercial Manufacturers. 1993. Sporting Arms & Ammunition Manufacturers' Institute, Inc., Wilton, Conn. USA.

Winchester Ammunition Reloader's Manual, 15th Edition. 1997. Winchester Group, Olin Corporation, East Alton, IL, 62024.

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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