Patent Publication Number: US-2010122468-A1

Title: Universal Headspace Gauge

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     This invention relates in general to an apparatus that provides an accurate method of measuring the length of ammunition cartridges between their flat base and upper portions of the cartridge. This includes the tapered case shoulder, the mouth of the case, the ogive of the bullet, or to the tip of the bullet. It is also suitable for comparing the dimensions of different cartridges. 
     2. Discussion of the Related Art 
     Many hunters and long range shooters reload their ammunition cartridges to gain accuracy while saving money on ammunition, compared to buying factory loaded ammunition. In the reloading process, cartridges need to be resized and assembled to specific dimensions. Reloaded ammunition needs to be measured accurately to ensure that proper dimensions are maintained. One long existing problem is in taking measurements between the flat base of a cartridge case and its upper surfaces. One of the most important case measurements is the from base to the shoulder. This is known as headspace. The benefit of taking accurate headspace measurements will result in reloaded ammunition being more reliable, more accurate and it will also extend the lifespan of fired cases. 
     SUMMARY OF INVENTION 
     This device is an adjustable v-block that is attached to a digital indicator. It is able to take several different measurements on any type of ammunition cartridge without using bushings or special tools. It provides the most accurate method to get repeatable measurements, by using the uniform downward spring pressure provided by the digital indicator. Several different cartridge comparisons and measurements can be made with this device that are needed to reload quality ammunition. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of the entire Headspace Gauge. 
         FIG. 2  is a view of the adjustable V-Block in operating position. 
         FIG. 3  is a multi-sided view of the adjustable V-Block. 
         FIG. 4  is a shadow view of a cartridge. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, which are for the purpose of illustrating the preferred embodiment of the invention and not for the purpose of limiting the same, the drawing  FIG. 1  shows a view of the complete Universal Headspace Gauge.  FIG. 2  shows an enlarged view of the adjustable v-block  90  positioned around a loaded ammunition cartridge  80 . The shadow view of  FIG. 4  is shown for clarification in describing the purpose and function of the adjustable v-block  FIG. 3 . The headspace gauge  FIG. 1  is vertically raised or lowered to measure different lengths of any cartridge  FIG. 4 . The v-block  FIG. 3  provides an adjustable  3  contact, V shaped surface  70  that provides an upper reference point for measuring from the tapered sides of cylindrical surfaces such as in  FIG. 4  from the case shoulder  5  or the bullet ogive  30  down to the cartridge base  6 . 
     The adjustable v-block  FIG. 3  is a flat element that is attached to the stem  85  in  FIG. 2  of a conventional depth indicator (digital type or mechanical dial) by a single screw that is inserted through hole  50  in  FIG. 3 . The v-block  FIG. 3  can also be installed upside down to make the headspace gauge  FIG. 1  more accessible for left hand operators. The v-block  FIG. 3  is mounted horizontally having a V-shaped interior surface  70  that directly faces the tip of an adjustable screw  60  which is mounted on the opposing side of the v-block  FIG. 3 . The adjusting screw  60  establishes a particular size of the expandable triangular opening that adjusts to provide a symmetrical outside diameter. The combined contact surfaces of the adjusting screw  60  and the v-shaped interior surface  70  establish a common upper reference point for measuring from the bullet ogive  30  or the cartridge shoulder  5  downward to the cartridge base  6 . The adjustable screw  60  is then set in the optimal position to perform measurements, and it is then secured in place with lock screw  40 . Lower surfaces of the v-block  FIG. 3  are flat, and they provide another upper reference point for measuring from flat surfaces such as in  FIG. 4  the case mouth  10  or to the bullet tip  20  down to the cartridge base  6 .