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The "Ranging Shot" Is A Regular Column In The IHMSA News
Published in The IHMSA News, the Official Publication of The International Handgun Metallic Silhouette Association
Published monthly except November/December - January/February
IHMSA on the web at http://www.ihmsa.org
Volume 17, Issue 10 Nov/Dec
 
  The Ranging Shot Email Todd:  TSPOTTI@worldnet.att.net
  With ( Comments or questions? )
Todd Spotti
 
Case Necks
     In my last column, I talked about the importance of paying attention to the cartridge caseís ďignition systemĒ i.e. the flash hole and primer pocket. This month, I thought Iíd talk a little about the other end of the case - the neck. Of course the neck is very important to accuracy because it holds the bullet.
 
     Right up front we have to ask ourselves ďIs this tedious procedure worth my time?Ē Well, it all depends. If youíre shooting a Contender, Encore, or similar firearm with a standard factory barrel (which are known for their generous chamber dimensions and long, long throats) the chances are that neck turning wonít do you a bit of good, so donít worry about it. There is an exception however which is based on the old saying ďItís never so bad that it canít get worseĒ.
 
     Get out your dial caliper, and check the wall thickness of some new brass cases that youíll use in your gun. However, before doing so, chamfer the inside and outside of the case mouth first. New cases often have a little ridge of metal thatís formed during the manufacturing process around the edge of the mouth which will throw off your measurements if itís not removed. OK, check the neckís thickness in at least four places. If there is a variance of .0015Ē or greater from the high side to the low side, experience has shown that it will negatively effect accuracy to a degree that it will be worth your while to neck turn the cases. If the variance is less than .0015, donít bother.
 
     On the other hand, if youíre shooting a Contender, Encore, or other gun with a custom tight fitting match chamber, it also is probably worth your time and effort to neck turn your cases. The reason we want to do this is because we want the bullet to be as closely aligned to the center of the bore as possible when the cartridge is in the chamber. The more the bullet is off set from the boreís center line, the more lateral and/or vertical stress it will be subjected to when it enters the rifling of the barrel. For instance, did you ever get a screw misaligned in a threaded socket? Of course. We all have. Weíve also on those occasions have sometimes (in spite of our common sense) continued to turn the screw in even though we knew it wasnít lined up properly, using greater and greater effort to get the d#%nn screw in there.
 
     Ok, similarly, when a misaligned bullet leaves the bore after being forced under enormous stress into the barrel, it will immediately start yawing around in response to that stress. The amount of yaw will be directly proportional to the amount of bullet off set. While itís yawing around itís also intermittently presenting a greater profile to what ever wind is out there, and therefore will experience more wind deflection. Eventually, the bullet should settle down and ďgo to sleepĒ - if the range is long enough, but the damage to accuracy will already have been done. So, if we have a match chamber, and/or if we determine that our brass is significantly thicker on one side than the other, weíll want to neck turn.
 
     Now there are a lot of neck turning tools out there and to be honest they all do a good job, so it comes down to a matter of convenience and preference.
 

"The Sinclair 1000 neck turning tool will help to fine tune your brass."

     Iíve been using a Sinclair 1000 tool for many years and have been happy with it except that the blade is easily adjustable going in but isnít if you want to adjust out. Additionally, it take three different allen wrenches (supplied) to set it up. I would have preferred if it was just one size wrench. Once it has been set up though, itís very easy to use. Although Iíve never used it, the new RCBS tool looks pretty nice and Iíve been meaning to try it out sometime. However, no matter what tool you use, they all work essentially the same i.e. the case neck fits on a mandrel and a cutting blade removes the metal.
 
     The first thing we need to consider is the fit of the case neck on the mandrel. That means that before we do any cutting, the case first has to be sized. This is necessary because we just canít have an expanded case neck slopping around on the mandrel during the turning process. Consequently, the expander ball of your sizing die should be anywhere between .0005Ē and .0015Ē larger than the neck turning mandrel. We want a fit where the neck will go over the mandrel with a smooth motion with just a bit of drag. To that end, youíll probably want to lube the mandrel with a good case lube. I use Reddingís or some times RCBSís. If your case neck wonít fit over the mandrel, it means  that your sizing dieís ball expander is too small and the die is squeezing the neck down too far. Your best option in those cases is to simply remove the mandrel from the cutting tool and chuck it into an electric drill. Then take some emery cloth and then polish the mandrel down to where itís a smooth fit for the sized case mouths.
 
     Ok, now take a case that you know is too thick on one side and clamp it into the turning handle. Now insert the case neck onto the cutting mandrel. Next, adjust the cutting blade down to where it just barely touches the brass on the high side. Remove the case from the mandrel, and adjust the blade down just a little bit more. Donít over do it. Put the case back on the mandrel and now start rotating the case forward under the blade. Go slowly and observe how the blade is taking off just the highest of the high spots on the brass. Be careful not to cut into the shoulder of the case. Ok, get your calipers and measure the neck. If youíre still getting a variance of more than .0015Ē from one side to another, move the blade down just a little bit more and cut again. Repeat until the proper thickness has been reached.
 
     By this time youíve probably observed, that the areas that have been trimmed away are a nice brilliant brass color, while the low spots that haven't been touched by the blade are dull looking. Itís a great temptation to lower the cutting blade even further down to trim away those low spots so the entire neck looks nice and bright. DONíT DO IT! When that case is fired, the chances are very good that the case neck is now way too thin for your sizing die. As a result, the neck wonít be sized down enough (if at all) to grip the bullet. The result is a ruined case. When neck trimming, itís very easy to over do things, so go slowly and carefully.
 
     Once you have your blade adjusted properly, lock it in place. Itís also not a bad idea to keep a spare case which has been turned with the tool as a dummy so when you have to readjust the tool after turning the cases for a different gun/caliber/cartridge you can use the dummy to bring the blade back to its original setting.
     Last point and reality check. Donít expect a wild and dramatic improvement in accuracy after neck turning. This procedure wonít turn a fair load into a great load and it wonít turn an average shooting gun into a tack driver. Nor is there any probable advantage when shooting at the regular full sized targets. Remember, weíre talking about handguns held by people with no use of artificial support who are shooting at fairly large targets. Neck turning will provide an improvement, but weíre talking about a fine tuning procedure here, not a miracle. Itís most valuable result will probably be experienced when addressing the shoot off and half scale targets. There, we need every fraction of an inch in accuracy that we can get, and thatís where the pay off will definitely come into play.
 
Reloading Presses, Dies & Concentricity
     One piece of advice youíve seen in my scribbling many, many times over the years is that when it comes to silhouette competition, buy the best that you can afford - no matter what it may happen to be. In fact, Iíve often said ďIf you can, stretch a little fartherĒ to buy the best quality. In the case of optics, guns, bullets etc. the principle is fairly obvious. However, when it comes to reloading presses and dies, the principle is often forgotten because we tend to take these things for granted i.e. a press is a press and a die is a die. Not really.
 

"Buying quality dies like these will insure case concentricity."

     If youíre thinking about buying a reloading press or some dies (the two are parts of the same mechanical system) and are thinking about an economy product, consider the following.
 
     A.  How well is the pressís ram aligned with the die on the top?
      B.  Is the shell holder machined perfectly parallel to the ram.
     C.  Is the shell holder machined perfectly parallel to the surface of the die hole at the top of the press?
     D.  Is the de-capping rod located in the exact center of the die?
     E.  Is the de-capping rod located in the exact center of its lock nut?
     F.  Is the expander ball located exactly centered on the de-capping rod or is it slightly offset?
     G.  Is the expander ball perfectly round or is it slightly lop sided?
     H.  Is the top of the die hole on the press perfectly parallel so the die isnít cocked to one side when screwed in?
     I.  Is the dieís lock ring perfectly parallel to the top surface of the press?
     J.  CRITICAL!!! Is the inside diameter of the die concentric with the outside diameter?
     K. Is the dieís de-capping rod perfectly straight or is it slightly bent?
 

"Precise tolerances in a press add up to accuracy."

     Does all this really make any difference? You bet it does! If each one of these eleven things was off by only half of one thousandths of an inch, weíd have a very non-concentric case, and the accuracy of any ammo loaded with such a press and dies would be definitely negatively affected.
 
     Ok, that being said, itís also a fact of life that very few of us have the means or the ability to check and measure all those features on our press and dies. So what do we do? First, buy the best quality you can afford.
 
     Second, to see if we really do have a concentricity problem with our current press and dies, we can check what itís doing to our brass. To do so, weíll need a dial gauge and a fixture to hold the gauge and case. With all the Chinese tool imports floating around, the cost of dial a gauge has really dropped to the point that just about anyone can afford one. As far as the fixture is concerned, there are a number of places to purchase them. Start at Sinclair International and shop around. 
 
     Ok, now take a couple of fired cases and clean the necks of any powder residue to insure it wonít affect our readings. Place the case in the fixture and position the dial gaugeís tip in the middle of the case neck and measure the amount of run-out. Note the results on a piece of paper. (It should be close to zero.) Now run a case into the neck sizing die with the de-capping rod and its expander ball removed. Again measure the run-out. The difference between the two readings will tell you the amount of run-out that the neck area of the die is imposing on the case neck.
 
     Now we want to follow the same procedure with the de-capping rod with the ball expander back in the die. This will tell you if itís the de-capping rod assembly that is causing the excessive run-out.
 
     By taking these two measurements, weíll know what part of the die is giving us excessive run-out (.004Ē or more). The die could:
  • - have an out of round neck
  • - have residue build up in the neck area (clean your dies)
  • - have an off kilter shell holder (try another)
  • - off center ball expander
  • - out of round ball expander
  • - bent de-capping rod
  • - cocked de-capping rod
  • - press problem
      Borrow a similar die from a friend to see if the problem is just your die. If so, call the manufacturer. If not, call the press manufacturer. However, if you buy quality, you probably wonít have a problem at all. If you canít afford to buy quality right away, save for it. Donít settle for junk. Quality is always worth the money.
 
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.