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Rifles, Reloading, Optics, Equipment
Reloading
Neck sizing for accuracy
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<blockquote data-quote="bigedp51" data-source="post: 1739975" data-attributes="member: 28965"><p><strong>You are at the mercy of the quality of your cases and what happens to them when fired.</strong></p><p><strong>If your case wall thickness is not equal when fired the case warps, the case body can become egg shaped and even become banana shaped. Full length resizing reduces the chance of the case causing the bullet to be misaligned with the bore. And gives meaning to the saying "the cartridge should fit the chamber like a rat turd in a violin case". </strong></p><p><strong></strong></p><p><strong>Meaning a warped neck sized case is not going to improve accuracy. And a full length resized case will give the cartridge case some wiggle room to allow the bullet to be self aligning with the bore.</strong></p><p><strong></strong></p><p><strong>NECO CONCENTRICITY, WALL THICKNESS AND RUNOUT GAUGE</strong></p><p><strong></strong></p><p><strong><img src="https://www.neconos.com/NEWDIAL2.JPG" alt="" class="fr-fic fr-dii fr-draggable " style="" /></strong></p><p><strong></strong></p><p><strong>Also referred to as "The Case Gauge," this item is designed to measure:</strong></p><p>1) The curved "banana" shape of the cartridge case;</p><p>2) The relative wall thickness variation of a cartridge case;</p><p>3) The cartridge case head out-of-squareness;</p><p>4) Individual Bullets - out-of-round "egg shape" and/or</p><p>curved "banana" shape (excepting very small bullets);</p><p>5) The seated bullet and cartridge runout of loaded rounds. The accuracy of any firearm is determined -- and limited -- by the quality of the ammunition shot in it. The effect of imperfections in ammunition is cumulative; each flaw adds to the influence of all others. Precision shooters spend much time and effort "uniforming" cartridge cases, using advanced techniques to eliminate variation. Yet until recently, one of the most important of these variations has not been susceptible to detection by any device readily available to marksmen.</p><p></p><p></p><p>Normal manufacturing tolerances cause brass cartridge cases to vary in wall thickness around the circumference of their bodies. Under the stress of firing, a case with such variation stretches more readily along its thin side, transferring more pressure to the bolt face at that point and introducing an unbalanced force which contributes to bolt whip and vibration of the barreled action in its bedding. This whip and vibration varies from one shot to the next as cartridges are fired with their thin sides randomly oriented at different angles, causing reduced accuracy. The problem is made even worse if the brass is too hard or springy to completely fireform to the shape of the chamber, in which event the greater stretching of the case's thin side will cause it to develop a curve along the length of its body. These "banana" cases cannot hold a bullet aligned with and centered in the bore, undercutting the effectiveness of the handloader's careful case preparation.</p><p></p><p>Fortunately the accuracy problems caused by wall-thickness variation can be minimized, or perhaps eliminated, if all cases are "indexed" -- fired with their thin sides always oriented the same direction in the chamber. This causes bolt whip to be minimized and consistent, and, while bullets will still be misaligned, they will all be misaligned the same way, which often produces accuracy like that of perfectly aligned and concentric ammunition.</p><p></p><p>All we need to index cases is a means of accurately locating each case's thinnest point. This is not possible with traditional micrometers or other measuring devices used by handloaders.</p><p></p><p>The patented NECO Concentricity, Wall Thickness and Runout Gauge™ is a unique tool. In addition to permitting all the runout measurements possible with other concentricity checkers, it features a "chord anvil" fixture which allows the handloader to measure the wall thickness of cartridge cases, to determine its uniformity, and to precisely locate the thickest or thinnest point in each case. Brass can then be sorted according to uniformity, and permanently marked for indexing.</p><p></p><p>Until the advent of this new NECO gauge, indexing and checking for straightness procedures have been neglected because of the difficulty of the necessary measurements, but are now very easy to perform. Several large commercial ammunition manufacturers have adopted the NECO gauge as a standard laboratory tool for quality control purposes.</p></blockquote><p></p>
[QUOTE="bigedp51, post: 1739975, member: 28965"] [B]You are at the mercy of the quality of your cases and what happens to them when fired. If your case wall thickness is not equal when fired the case warps, the case body can become egg shaped and even become banana shaped. Full length resizing reduces the chance of the case causing the bullet to be misaligned with the bore. And gives meaning to the saying "the cartridge should fit the chamber like a rat turd in a violin case". Meaning a warped neck sized case is not going to improve accuracy. And a full length resized case will give the cartridge case some wiggle room to allow the bullet to be self aligning with the bore. NECO CONCENTRICITY, WALL THICKNESS AND RUNOUT GAUGE [img]https://www.neconos.com/NEWDIAL2.JPG[/img] Also referred to as "The Case Gauge," this item is designed to measure:[/B] 1) The curved "banana" shape of the cartridge case; 2) The relative wall thickness variation of a cartridge case; 3) The cartridge case head out-of-squareness; 4) Individual Bullets - out-of-round "egg shape" and/or curved "banana" shape (excepting very small bullets); 5) The seated bullet and cartridge runout of loaded rounds. The accuracy of any firearm is determined -- and limited -- by the quality of the ammunition shot in it. The effect of imperfections in ammunition is cumulative; each flaw adds to the influence of all others. Precision shooters spend much time and effort "uniforming" cartridge cases, using advanced techniques to eliminate variation. Yet until recently, one of the most important of these variations has not been susceptible to detection by any device readily available to marksmen. Normal manufacturing tolerances cause brass cartridge cases to vary in wall thickness around the circumference of their bodies. Under the stress of firing, a case with such variation stretches more readily along its thin side, transferring more pressure to the bolt face at that point and introducing an unbalanced force which contributes to bolt whip and vibration of the barreled action in its bedding. This whip and vibration varies from one shot to the next as cartridges are fired with their thin sides randomly oriented at different angles, causing reduced accuracy. The problem is made even worse if the brass is too hard or springy to completely fireform to the shape of the chamber, in which event the greater stretching of the case's thin side will cause it to develop a curve along the length of its body. These "banana" cases cannot hold a bullet aligned with and centered in the bore, undercutting the effectiveness of the handloader's careful case preparation. Fortunately the accuracy problems caused by wall-thickness variation can be minimized, or perhaps eliminated, if all cases are "indexed" -- fired with their thin sides always oriented the same direction in the chamber. This causes bolt whip to be minimized and consistent, and, while bullets will still be misaligned, they will all be misaligned the same way, which often produces accuracy like that of perfectly aligned and concentric ammunition. All we need to index cases is a means of accurately locating each case's thinnest point. This is not possible with traditional micrometers or other measuring devices used by handloaders. The patented NECO Concentricity, Wall Thickness and Runout Gauge™ is a unique tool. In addition to permitting all the runout measurements possible with other concentricity checkers, it features a "chord anvil" fixture which allows the handloader to measure the wall thickness of cartridge cases, to determine its uniformity, and to precisely locate the thickest or thinnest point in each case. Brass can then be sorted according to uniformity, and permanently marked for indexing. Until the advent of this new NECO gauge, indexing and checking for straightness procedures have been neglected because of the difficulty of the necessary measurements, but are now very easy to perform. Several large commercial ammunition manufacturers have adopted the NECO gauge as a standard laboratory tool for quality control purposes. [/QUOTE]
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