Primers And Priming Tools

American primers come in two diameters, large and small. In both large and small sizes, there are pistol and rifle primers. Each of these also come in magnum and standard strength versions Thus, there are large rifle, large pistol, small rifle and small pistol primers.

LARGE pistol and rifle primers are of the same diameter, however the HEIGHT differs.

My primer pocket uniformer literature warns that LARGE RIFLE primer pockets should be .128" to .132" deep, and that LARGE PISTOL primer pockets should be .118" to .122" deep.

It would then follow that using LARGE RIFLE primers in cases made to use LARGE PISTOL primers could result in the primer being above the case head, a potentially dangerous condition.

If you make sure that your primers are BELOW the case head, you'll be fine. (My Remington # 2 1/2 Large Pistol primers measure .121" to .1245"high, and  #9 1/2 Large Rifle primers measure .131" to .133" high.)

SMALL rifle and pistol primers are the same diameter and height.

Some manufacturers make primers that are specialized; these include Magnum or high power primers, and Bench Rest, (probably) more carefully made primers. Remington, Winchester, Federal, CCI and others manufacture primers.

De-priming The Case

Primers may be removed in the press, in the sizing/de-priming die. Some reloaders prefer to remove primers as a single first operation. Tools are available made by Jerry Simmons and Werner Wolf that both de-prime and re-prime cartridge cases. A much less expensive de-priming tool is the Lee Punch and Base set used with a plastic mallet.

Re-priming The Case

When a primer is fired, it leaves a brittle, black crust inside the primer pocket. This crust can build up and present problems when seating new primers. At the very least, it can act to cushion the firing pin impact, and give weak ignition. Always clean the primer pocket before re-priming. It only takes a moment, and doesn’t require anything more than running a toothpick around the inside. I’ve also used a very small screwdriver for this. There are a variety of commercial scrapers and brushes available for this too.

The Lee priming tools are excellent and inexpensive. Priming can also be done with a Lyman tong tool and dies, or with a reloading press and primer arm.

You should be able to feel the primer bottom out in the primer pocket as you prime the case. Don’t force the primer any further, just feel it in until it seats. The primer should be below or at the very least level with the base of the case. Feel the base of the case with your finger; it is easy to tell if the primer is below the base. If you can’t feel it, put a straight edge on the base and see if it touches the primer, or stand the case up on a flat surface and see if it rocks on the primer.

DON’T SHOOT IT IF THE PRIMER IS ABOVE THE BASE! There is a real danger that the gun will go off as you chamber the cartridge.

Take out the primer, clean the primer pocket and try again. Drop the removed, live primer in a tin of oil to deactivate it. Never try to re-use a primer. The de-priming could well have cracked the priming pellet, which could fallout, giving you a misfire or a hang-fire.

Remington primers sometimes seem to fit Remington cases better than some other brands of cases. Primers and cases made by the same manufacturer sometimes seem to go together better than primers and cases made by different manufacturers. This is not always true, and it is not of great importance, but it argues for Remington cases if Remington primers are used.

I have had only one lot of cases that had primer pockets too shallow to allow primers to fit flush with or below the base. These went in the trash and new cases fixed the problem.

It is frequently said that changing primers can dramatically change accuracy. I have never found that to be true, I wish it were that easy.

For cast bullet loads below about 1600 fps, I use Remington 2–1/2 Large Pistol primers exclusively. I can’t prove that they shoot better, but I think they do, in cartridges including the 45/70 and 300 Winchester Magnum. (since I wrote this I can't find any Remington primers and have been using Winchester WLP Pistol primers with good results. I like those nickeled primers, though.)

I believe that primer selection is a lesser important variable in reloading cast bullets, and that sticking with one brand of primer makes the most sense.

Over-Primer Wads

Some Black Powder shooters have reported using wads over the primers. This is claimed to reduce the variation in velocity with these black powder charges. Some smokeless powder shooters like to use wads to prevent tiny granules of ball powders from entering the primer pocket. I’ve not seen any real studies on this, but they feel that there’s a good chance that these granules of powder can’t help but add to the force of the primer. And since there would be granules running in and out with handling, feeding, etc, the ignition would vary. A disk of paper at the bottom of the primer pocket eliminates this possibility.

One method is to place a piece of paper, such as newsprint, inside the case-over the primer-before the powder charge is put in the case. There have also been reports that sometimes these wads have been found in the case or even in the barrel after firing. It is conceivable that a paper wad in the barrel or in the case might affect the accuracy of the next shot. Some users of these wads in black powder loads have reported that they no longer use them, and have begun using Remington 2 1/2 Large Pistol primers.

A second method is to place a piece of paper-perhaps newsprint again-between the primer and the primer pocket when re-priming. When the primer is seated through the paper, the edge of the primer will cut out a piece of the paper and put it below the primer in the primer pocket. This method eliminates any possibility of the wad ending up in the case or barrel after firing. I have never used an over-primer wad.

Most reloading dies de-prime the case in the sizing step, and most presses have a provision for re-priming on the upstroke at that step. I de-prime pistol cases and some rifle cases in the press with the appropriate die.

I don't prime in the reloading press because I think that I have to clean the primer pocket and priming by hand, as an individual operation is better. I de-prime most rifle cases with a Lee punch and base set (or a Simmons De/Re primer or a Lyman #2 tool made around 1890). I prime most cases with the Lee Auto Prime, a wizard tool. RCBS and Sinclair make re-priming tools for a lot more money than the Lee. A guy gave me an RCBS priming tool and I gave it away to a guy who gave it away.

(The Lee Loader uses a punch and base system for priming that now and again results in a loud bang. About three of these bangs cause most beginners to spring for the $13 Lee Auto Prime.)

"The bangs are caused by the seating tool design, which is intended to seat the primer just a trifle below the head of the case, as it should be. However, sometimes a long primer - possibly in conjunction with a short primer pocket - will ‘bang’ as it is being seated.

Interestingly enough, there have been occasions when I only needed to load a round or two. Or perhaps it was an odd case that wouldn’t fit my tools. Either way, a primer can be easily and safely seated with nothing but a steel rod, a hammer and a hard, flat surface. Simply place the appropriate primer on the surface, and set the de-primed case over it. The slight rounding of the primer pocket will enable you to easily feel the primer slip into the top of the pocket. You’ll have to hold the case in place with one hand while you insert the steel rod with the other. (The rod must project above the mouth of the case.) Then pick up the hammer and drive the case down over the primer, until the case is flat against the hard surface. The primer will be exactly flat and even with the base of the case.

Although this may appear hazardous, I have never once experienced a ‘bang’ in some 3 decades of intermittent practice. A little reflection should explain why: the primer pellet IS very sensitive to being impacted. But when driving a case down over it, the primer pellet is not compressed or impacted!  It remains between the tip of the anvil and the bottom (inside) of the primer cup. It can’t come under any impact or compression until the anvil has been firmly seated at the bottom of the primer pocket. And the process is such that no matter how hard you pound with the hammer, you simply can’t drive the primer any deeper than that." Ken Mollohan

I have been told many times down through the years that if a gun has a light hammer fall the groups fired with that gun will string up and down. I had always assumed that this was true as the persons reporting this effect were very respected men who had done a lot of really serious shooting.

     Back before the primer shortage developed I had made a test rig to test primers all by themselves (a stand alone test of primers). Basically I was able to hit primers with a very repeatable force and was determining how much force it took to reliably fire them as well as the velocity that they would impart to a specially made pellet. Results were determined by measuring the velocity of the pellets about fifteen feet from the muzzle of the test rig.

This testing was discontinued when the supply of the desired primers for testing dried up.

These tests have not at this time been resumed. Two observations were, however, made from the data collected at that time. One: the observed average velocities were not affected by how hard the primer was hit. Second: about one primer in five regardless of make or grade was to a noticeable amount deviant from the group average. This took the form of either being significantly higher OR lower in velocity than the average.

These properties were discussed with various shooters during the time that supplies of the various primers were not available. I was often asked if the same results would be observed if I were actually shooting cartridges loaded with powder and bullet. There was at that time no practical way that I could test this idea. As a result the question was left hanging with no real answer.

Recently a method was conceived that would readily permit study of this as well as other questions. I had a spare Douglas 32-40 barrel blank with a 1-12 inch twist that could be devoted to a test program. A breech system was devised that would permit various firing pin impacts on the primer to be studied. It is not a fast system but permits one shot to be fired about every two minutes. Bullets are weighed, lubricated and swaged so that they are as uniform as can practically be made. All of the shots in the test were fired from my rail gun at a range of 100 yards. This test was designed to equate obtained accuracy with primer impact.

It was determined that six five shot groups under three different striker impact forces would be studied. The cartridge case was my 32-357 Magnum which was developed back in about 1971 but not really used until about 1993 when I received a barrel blank from Ken Bresein that was cut with Pope style rifling. It is the cartridge that my current competition gun is chambered for. The bullet is a 200 grain basic bullet from a Colorado Shooter's Supply mold. the bullet is subsequently lubricated and swaged before shooting. The swage is one of my own design and build. The powder charge for this test is 8.1 grains of Accurate Arms #7. Primers for this test were the Remington 7 1/2. One cartridge case was used for all shooting in this test. Powder charges were cast from a Redding M 3 BR powder measure and not individually weighed. Groups were evaluated by two methods, extreme spread of the two widest bullet holes and by the mean radius concept which studies all of the shots in the group.

In studying the velocity of all the shots fired on the record groups it was interesting to observe that about one shot in five was deviant from the group average by more than five feet per second. As most groups did not have an extreme velocity spread of more than ten feet per second this was considered significant. The deviance occurred both ways from the average velocity of the group. Some deviant shots measured a low velocity and others a high velocity. When more than one deviant shot occurred within a given group of five shots it would raise or lower the group average. Because of this, all comparisons were to the overall average velocity as all shots were fired under basically the same conditions of loading, temperature and load.

I will report the average velocities of each of the 30 shot study groups and the final average velocity for the total 90 shots of the test.

In a similar manner I will report the average velocity spread within each set, the average standard deviation, the average extreme spread and the average mean radius. All averages taken on six five round groups.

     This I believe shows beyond any reasonable doubt that accuracy is not affected one way or another by the force of the firing blow. If the primer goes off it goes off and the amount of energy transmitted to the powder is not affected by the impact energy of the firing pin. Even those primers that had to be hit twice in order to initiate ignition showed no difference from those that went off on initial impact.

While I believe that this eliminates one source of alibis for groups that are strung out up and down, it is one less thing that we as shooters of various old and new guns have to be concerned about. After completing this series of tests I can say without hesitation that accuracy is in no way affected by the force of the firing pin impact on the primer.

Reloading BERDAN primed cases is a bit more bother than Boxer primed cases, but not that much more so. The main problem is removing the spent primers. There are special tools sold to pry out used BERDAN primers, and articles on the internet telling how to make such a tool from a file or screwdriver; but I use water pressure.

Tools to remove the primers:

The original Swiss primers are held (crimped) by several small dimples in the primer pocket. This makes primer removal a bit harder with once-fired brass. However, these primers will come out with one or more sharp blows as described later. Once the original primers are removed, I scrape off these little dimples with a tapered screwdriver notched to fit over the anvil. Thereafter, the replacement primers come out quite easily.

ROD ... a 5/16" X 3.5" steel rod is slightly tapered using a drill and fine emery cloth. This takes about one minute and only has to be done once, of course.

FACE CLOTH and PLASTIC WRAP ... an old face cloth on top of plastic wrap is used to catch

 the water. PLIERS [to hold the rod so you don't hit the thumb] and HAMMER, and a thin wooden STICK to poke out any primers stuck in the block.

Steps to Remove Primers

Re-Priming

I don't know if it's necessary, but I scrape out the primer pocket and scrape the face of the anvil with a small screwdriver and poke out the fire-holes with an opened safety pin before full length resizing. Any distortion of the case caused by the primer extraction process is corrected by the resizing die. I usually discard one or two cases each session (36-42 rounds/session) due to cracked cases. The crack usually occurs just above the web, but some times near the mouth. I have never annealed the cases. I load fairly light [40g 4895 with 150g surplus M2 bullets]; the primers might be harder to extract if I used a hotter load.

The Russian BERDAN primers [bought in a lot of 5,000 from PMC/Eldorado Cartridge in Nevada] are a mite larger than the Boxer large rifle primers, but they work in a hand-held Lee Autoprime okay. They seat a little deeper than the original Swiss primers, but they work.

		One sharp tap should do it