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Published in The IHMSA News, the Official Publication of The International Handgun Metallic Silhouette Association
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Volume 17, Issue 9 October
  The Ranging Shot Email Todd:
  With ( Comments or questions? )
Todd Spotti
Flash Hole / Primer Pockets
     “Good enough.” Those are words that you’ll never hear from a serious silhouette shooter. Every competition shooter, no matter what the sport, wants to wring every last .001 of an inch in accuracy out of their loads as possible.
     However, there are so many variables in shooting that we have absolutely no control over (wind, mirage, sun angles and brightness, background, etc.) that one can only wonder how we do the things that we do as well as we do them. The reason a serious shooter can accomplish those things is because they spend copious amounts of  time, money, and energy on the variables that they can control - particularly when it concerns their loads.
     One of the more esoteric procedures that a careful competition shooter will use in preparing their loads will be flash hole reaming. It’s no secret that the flash holes found in our cartridge cases often leave something to be desired as far as precision is concerned. In fact, I’ve seen flash holes on some lots of brass where it seemed like they were just a casual afterthought. For instance, I remember one lot of  brass where the flash holes were elliptical. Another where several of the holes were undersized to the point that the de-capping rod of my sizing die got jammed in the hole, and when I lowered the ram of my press, the rod was literally pulled out of the die. Then there are the cartridge cases where a burr is formed around the flash hole on the inside by the hole punching or drilling process. Any one of these three conditions>
  • 1. Misshapen/out of round hole
  • 2. Undersized hole
  • 3. Burr around hole
 can cause distorted flame patterns from the primer and in turn, distorted ignition. However, put all three conditions together and you’ve got trouble for sure. Ever have a situation when you were shooting a known, accurate load and everything was lined up perfectly and the shot ends up going off into the boonies? The three conditions outlined above could very well have played a factor in the miss. The point here is that we want perfect consistency in our loads when shooting silhouette competition.
     There are a lot of tools available in all kinds of price ranges that will help us do this job and I’ve used a number of them. As a result, I’ve formed some definite ideas about what makes a good flash hole de-burring tool and what doesn’t.
     First of all, I like those with a decent sized handle. I own some that are nothing more than a little metal spindle with a little plastic electrical insulator cap glued on the end for a “handle”. These itty, bitty tools are hard to handle and have no torque at all when you’re trying to ream out a stubborn burr or an undersized hole. Another problem is the fact that it’s impossible to perfectly align the tool with the flash hole. This is important because we don’t want to end up canting the hole to the side when we ream it out. Now some of these tools will have a little sliding cone on the spindle that rests on the case mouth to center it with the flash hole. This is a step in the right direction but even so, because the tool is so small that holding the case, the tool, and keeping the cone in line is very awkward. I find it to be somewhat difficult to handle the whole mess. No, there’s nothing like a decent sized handle to give you a good grip.
     Another feature that I really like is a pilot rather than a cone on the cutting rod. A pilot is a guide that precisely fits into the neck of the case and will hold the cutting rod in perfect alignment with the flash hole. This insures that the hole will be cut true and straight. Pilots will also feature a set screw to lock them in place on the cutting rod. This also allows you to control the depth of the cut. This is a valuable feature as you want to go down just enough to get rid of any burrs, uniform the size of the hole, and perhaps put a slight bevel around the flash hole, but no deeper. We don’t want to compromise the strength of the case by going too deep.

"Primer pockets can be quickly uniformed with a crank type tool."

     Sinclair International, my favorite source of precision reloading tools has just come out with flash hole reaming tool that has these features.
     The handle is made of green plastic and is of an anti roll type design. In other words, if you place it on an inclined surface, it won’t roll off. Most importantly, it’s just under an inch in diameter and therefore gives a decent grip to the hand. At the base of the handle is what appeared to be a sliding steel collar with a set screw. At first I thought this was a sliding stop to set the depth of the reamer cut. I quickly discovered that the collar was fixed to the handle and actually was holding the cutter rod in place in the handle. When I backed out the set screw and removed the rod from the handle, I found that the other end of the rod sported another reamer blade as a spare.
     The steel pilots are what really sets this tool apart. They are made in house by Sinclair and are available in a  wide variety of diameters. The workmanship is very good. They slip on the cutter rod and then are fastened in place with a set screw. The thing that impressed me the most about the pilots was the fact that they are precisely sized to fit into the neck of a new un-sized cartridge case.
     I tried the pilots in four different types of cases (224, 6mm, 7mm, and 357) and the fit was perfect with absolutely no looseness and only the very slightest hint of drag when being inserted. In other words, it was a perfect fit. Another thing that impressed me was the fact that the portion of the pilot that fitted into the case neck was nice and long i.e. just under a half inch and therefore is a very deep, secure fit. This insures that the cutting rod will be properly lined up with the flash hole and can’t slip around on the case mouth like one of those cones.
     The bottom line here is that the Sinclair flash hole tool is a high quality product that will last a lifetime and allows you to do this valuable task easily and quickly. The pilots are sold separately so you can buy just the ones that you need.

"The Sinclair flash hole reamer is a high quality tool and makes quick work of the job."

     While we’re talking about what goes on at the rear of the case, let’s discuss primer pockets. As you might guess, primer pockets are one of those things that most people take for granted. They’re just there. You stick a primer in and you forget about it. Well, yes and no.
     Again, primer pockets get no respect and yet they’re a very important part of the case’s ignition system. The fact of life is that the depth of primer pockets, more often than not, will vary significantly, with most being shallow, while others will be in spec and therefore significantly deeper. Additionally, they will sometimes be off kilter as well i.e. be higher on one side than the other. Another very common situation is the fact that the inside edges of almost all primer pockets are rounded rather than square. To add insult to injury, the bottoms of the pockets are almost never flat, but actually will be concave to varying degrees.
     So why should we care? Basically, there are three reason why we should care. Ignition. Ignition. Ignition.  Primers are designed and built on the assumption that they’re going to be sitting on a perfectly flat surface. Obviously with run of the mill primer pockets there’s almost a 100% chance that’s just not going to happen. Without a uniform and flat primer pocket, it’s almost impossible to get the best primer ignition. Without uniform primer ignition, we’ll get irregular powder burning, and with irregular powder burning we’ll get larger groups. So why’s that?
     Simply because when a primer is seated high, low, canted, or not firmly bottomed out in the pocket, it will receive irregular amounts of force when struck by the firing pin. If not bottomed out, it could even move forward slightly, cushioning the blow somewhat. In fact, it’s been shown that the force of the firing pin blow in these very common situations can vary as much as 20%. Result? Inconsistent ignition and bigger groups. So what do we do?
     We have to use a uniforming tool to reshape the pockets into a proper shape. The tools come in three general categories: hand, crank powered, or power screw driver powered. Again, there are several sources for these tools but, as you guessed, I like Sinclair International for these kinds of products. They have their own in house tools and they also sell quality tools from others as well. For a small number of cases (50 or under) a hand tool is fine. Make sure it has a decent handle on it though for ease of use and sufficient torque with minimal effort. For 50-100 cases, I use a Forster hand crank set up with a Sinclair cutting tool mounted. This operates something like a manual pencil sharpener and does the job pretty fast. One thing though, the Foster crank handle has a knurled knob which kind of rubs the side of my forefinger raw with extended use. Consequently, I wrapped some tape around the rough knurling thus proving a smooth surface. Situation remedied. When working with over a hundred cases, a power screw driver goes a long way to make this tedious job bearable.
     So there it is. Like with spotting scopes, we tend to pay the most attention to what’s going on up at the front . We’ll lock in on the size of the objective lens, the coatings, etc. and pay no attention on the characteristics of the eyepiece back at the rear - a huge mistake. With our cases, we’ll trim them them up front, chamfer the mouth, uniform the necks, etc. and then will often ignore the components of their ignition system located in the rear i.e. the flash holes and the primer pockets. If we want to wring the most accuracy out of our loads, an investment of a few more moments of our time will bring a significant reward.
Small Arms Production
     I recently received a very interesting Industry Intelligence Report from the National Shooting Sports Foundation, the industry trade group that represents the shooting industry in the U.S. They also sponsor the industry’s annual Shot Show. The report was essentially a summary of arms production in the United States with 2004 being the most recent figures available. Here’s a couple of interesting facts drawn from the report.
  • 1.  Rifles accounted for 43% of firearms production
  • 2.  Shotguns = 24%
  • 3.  Pistols (semi autos & single shots) = 24%
  • 4.  Revolvers = 9%
  • 5.  The greatest number of handgun imports were from Austria.
  • 6.  The greatest number of shotgun imports were from Italy.
  • 7.  The greatest number of rifle imports were from Canada.
     Handgun production figures were also very interesting. These are just a few numbers from some of the manufacturers that most silhouette shooters are familiar with. There were a total of 48 manufacturers listed in the report. I was very surprised that the vast majority of the listed manufacturers were companies that I had never heard of and who were producing a very significant number of handguns. Perhaps the name of the company and the brand name of their product were different.
  • Smith & Wesson - 235,616
  • Ruger - 189,312
  • Taurus - 12,248
  • Colt - 10,173
  • Dan Wesson - 1010
  • TC - 8,677
  • Freedom Arms - 825
     Just as a point of comparison, TC produced just over 45,000 long guns compared to its 8,677 handguns. Lastly, Remington is the largest manufacturer of firearms with 19.3% of all produced, Ruger is second with 14.5%, and Smith & Wesson comes in third - Buy American.
Good luck and good shooting. Todd

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Warning: All technical data mentioned, especially handloading and bullet casting, reflect the limited experience of individuals using specific tools, products, equipment and components under specific conditions and circumstances not necessarily reported in the article or on this web site and over which IHMSA, The Los Angeles Silhouette Club (LASC), this web site or the author has no control. The above has no control over the condition of your firearms or your methods, components, tools, techniques or circumstances and disclaims all and any responsibility for any person using any data mentioned. Always consult recognized reloading manuals.