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The Guru Measures Groups

OBSERVING A FELLOW HUNTER, RELOADER, OR CASUAL SHOOTER CORRECTLY MEASURING SHOT GROUPS, BRINGS A SMILE TO MY FACE. IT ALSO CLEARLY IDENTIFIES THAT PERSON, AS SOMEONE YOU MIGHT ACTUALLY LEARN SOMETHING FROM !!!!!!
SADLY, I HAVE WITNESSED “WELL KNOWN SHOOTING AUTHORS” WHO REPEATEDLY OVER MANY DECADES, LED THE READER TO BELIEVE A CARPENTERS TAPE-MEASURE & EXPRESSING THE SHOT GROUP SIZE “FRACTIONALLY” (1/32″, 1/16″, 1/8″, 1/4″, ETC.) IS THE PROPER WAY TO DO THIS—WRONG !!!! YOU MUST THINK & MEASURE LIKE A FIRST-CLASS MACHINIST (.062″, .125″, .250″, .500″ ETC.)

SO FOR THE BENEFIT OF OUR LOYAL READERS, “UNCLE GURU” WILL BE TEACHING YOU THE CORRECT & MOST PRECISE METHOD OF ACCOMPLISHING THIS TASK. “SHOOTER READY, STAND BY…..BEEP !!!!!”

SHOT GROUPS IN THE USA, ARE ALWAYS EXPRESSED IN “THOUSANDTH’S OF AN INCH / .000” & “CENTER TO CENTER” (CTC).THE REMAINDER OF COUNTRIES ON PLANET EARTH, EXPRESS NUMERICAL DIMENSIONS, USING THE METRIC SYSTEM (CENTIMETERS / MILLIMETERS (CTC). TO HELP YOU GAIN A BETTER UNDERSTANDING OF HOW THIS PROCESS IS ACCOMPLISHED, I HAVE ATTACHED SOME PHOTOS. DIRECT YOUR ATTENTION TO PICTURE #1………………

PHOTO #1: THE TOOLS YOU WILL NEED. A 6″ DIAL MICROMETER IS PICTURED, BUT A DIGITAL VERSION IS MUCH EASIER TO READ, ESPECIALLY FOR THOSE WHOSE EYES ARE 50 + YEARS OLD !!!!!!

PHOTO #2: IDENTIFY THE 2 HOLES FARTHEST APART.

PHOTO #3: USING THE STRAIGHT-EDGE & PEN, DRAW A LINE ALONG THE REAR EDGE OF THE FIRST BULLET HOLE. REPEAT THE SAME PROCESS FOR THE OTHER HOLE. BE SURE TO KEEP THE LINES SQUARE & PARALLEL TO EACH OTHER.

PHOTO #4: OPEN THE JAWS & GENTLY CLEAN THE FACE OF ANY DIRT / DUST. GENTLY CLOSE JAWS & CONFIRM THE INSTRUMENT HAS BEEN “ZEROED” BEFORE USE. OPEN THE JAWS AGAIN & CAREFULLY MEASURE THE SPACE / GAP BETWEEN THE 2 LINES. WRITE THIS TOTAL ON THE TARGET, SOMEWHERE NEAR THE 2 LINES. THAT NUMBER IS THE “OTO” MEASUREMENT.

PHOTO #5: SUBTRACT THE BULLET’S DIAMETER (.000″) FROM THE TOP NUMBER AND THIS FINAL TOTAL WILL EQUAL THE “CTC” MEASUREMENT. CONGRATULATIONS, YOU HAVE JUST LEARNED HOW TO CORRECTLY MEASURE A SHOT GROUP !!!!

IMPORTANT NOTATION: BULLET DIAMETER MUST BE EXACT & NOT SIMPLY GLEANED FROM THE NAME OF THE CARTRIDGE FIRED. TO ASSIST YOU, I HAVE INCLUDED THE DIAMETER OF THE MOST COMMON RIFLE & HANDGUN BULLETS:
RIFLE: .224″, .243″, .257″, .264″, .277″, .284″ & .308″
HANDGUN: .355″, .357″, .400″, .451″, & .452″

CREDITS: I WISH TO THANK MY DEAR FRIEND & SHOOTING BUDDY, OF THE PAST 30 YEARS, FOR HIS ASSISTANCE TO MAKE THIS SPECIAL ASSIGNMENT A SUCCESS. “THANKS BRO….OOORAH !!!”

SHOOTER: RANDAL DAVID, LAKE CHARLES, LA.
SHOOTING RANGE: “S-W LOUISIANA RIFLE & PISTOL CLUB”, LAKE CHARLES, LA.
DISTANCE: 100 YD. BENCH-REST. RIFLE SUPPORTED IN HEAVY STEEL SHOOTING JIG
RIFLE: HOWA MODEL 1500, .22-250 REM.
STOCK: HOGUE SYN.
TRIGGER: TIMNEY
AMMO: HORNADY 55 GR. “SUPER PERFORMANCE”
OPTIC: VORTEX 3-9 X 40 MM “DIAMONDBACK”

UNCLE GURU