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    • #27698
      Sgt. Mike
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      The slow twist in the 30 caliber I’ll use 2700 fps as the model according to the charts the following bullets should produce stability giving a Miller SG of 1.4 or better as the temps go up (this was calculated ate 59 degrees) so does the stability factor, same as length short = higher SG Factor = better stability :

      1-14″ Twist the following bullets should produce stability giving a Miller SG of 1.4 or better at 59 degrees (1.050″ Max Length)
      Caliber weight description length Plastic Tip length Manufacture

      0.30885Round Nose (Sports Master)0.535Sierria
      0.308100Short Jacket0.562Hornady
      0.308110Round Nose SP 30 Carbine0.602Speer
      0.308110Hollow Point0.614Speer
      0.308110Full Metal Jacket (Pro-Hunter)0.663Sierria
      0.308110Round Nose (Pro-Hunter)0.663Sierria
      0.308110Full Metal Jacket0.668Hornady
      0.308110Round Nose TMJ 30 Carbine0.676Speer
      0.308110Round Nose0.680Hornady
      0.308125HP/FN (Pro-Hunter)0.725Sierria
      0.308110Hollow Point (Varminter)0.795Sierria
      0.308110Spire SP0.804Speer
      0.308110Spire Point0.827Hornady
      0.308130Flat Nose SP/cann 30-30 Win0.829Speer
      0.308130Hollow Point0.860Speer
      0.308125Spitzer (Pro-Hunter)0.879Sierria
      0.308123Full Metal Jacket0.892Lapua
      0.308123Full Metal Jacket Cutting Edge0.892Lapua
      0.308123Spitzer0.892Lapua
      0.308150Round Nose (Pro-Hunter)0.895Sierria
      0.308150Round Nose0.905Hornady
      0.308150Flat Nose (Pro-Hunter)0.907Sierria
      0.308100HP Cutting Edge0.912Lapua
      0.308100HV0.920GS Custom Bullets
      0.308110Varmageddon FB Tipped0.920Nosler
      0.308125TNT™ HP0.920Speer
      0.308150Flat Nose SP/cann 30-30 Win0.920Speer
      0.308110V-Max0.926Hornady
      0.308110Match Target FB0.938Berger
      0.308115Match Target FB0.942Berger
      0.308150Mega0.943Lapua
      0.308100X Flat Nose0.945Barnes
      0.308150Mag-Tip SP0.965Speer
      0.308135Spitzer – Single Shot Pistol (Pro-Hunter)0.967Sierria
      0.308110Flat Base0.971ALCO
      0.308170Flat Nose (Pro-Hunter)0.996Sierria
      0.308170InterLock® Flat Point1.002Hornady
      0.308107SP1.010GS Custom Bullets
      0.308150Grand Slam™ SP1.020Speer
      0.308125Match Target FB1.026Berger
      0.308125SST®1.029Hornady
      0.308170Partition™ Round Nose1.030Nosler
      0.308125Flat Base1.037ALCO
      0.308110Tipped Triple-Shock™ X Flat Base1.047Barnes

      1-16″ Twist the following bullets should produce stability giving a Miller SG of 1.4 or better at 59 degrees (.960″ Max Length)
      Caliber weight description length Plastic Tip length Manufacture

      0.30885Round Nose (Sports Master)0.535Sierria
      0.308100Short Jacket0.562Hornady
      0.308110Round Nose SP 30 Carbine0.602Speer
      0.308110Hollow Point0.614Speer
      0.308110Full Metal Jacket (Pro-Hunter)0.663Sierria
      0.308110Round Nose (Pro-Hunter)0.663Sierria
      0.308110Full Metal Jacket0.668Hornady
      0.308110Round Nose TMJ 30 Carbine0.676Speer
      0.308110Round Nose0.680Hornady
      0.308125HP/FN (Pro-Hunter)0.725Sierria
      0.308110Hollow Point (Varminter)0.795Sierria
      0.308110Spire SP0.804Speer
      0.308110Spire Point0.827Hornady
      0.308130Flat Nose SP/cann 30-30 Win0.829Speer
      0.308130Hollow Point0.860Speer
      0.308125Spitzer (Pro-Hunter)0.879Sierria
      0.308123Full Metal Jacket0.892Lapua
      0.308123Full Metal Jacket Cutting Edge0.892Lapua
      0.308123Spitzer0.892Lapua
      0.308150Round Nose (Pro-Hunter)0.895Sierria
      0.308150Round Nose0.905Hornady
      0.308150Flat Nose (Pro-Hunter)0.907Sierria
      0.308100HP Cutting Edge0.912Lapua
      0.308100HV0.920GS Custom Bullets
      0.308110Varmageddon FB Tipped0.920Nosler
      0.308125TNT™ HP0.920Speer
      0.308150Flat Nose SP/cann 30-30 Win0.920Speer
      0.308110V-Max0.926Hornady
      0.308110Match Target FB0.938Berger
      0.308115Match Target FB0.942Berger
      0.308150Mega0.943Lapua
      0.308100X Flat Nose0.945Barnes

      1-17″ Twist the following bullets should produce stability giving a Miller SG of 1.4 or better at 59 degrees (.925″ Max Length)
      Caliber weight description length Plastic Tip length Manufacture

      0.30885Round Nose (Sports Master)0.535Sierria
      0.308100Short Jacket0.562Hornady
      0.308110Round Nose SP 30 Carbine0.602Speer
      0.308110Hollow Point0.614Speer
      0.308110Full Metal Jacket (Pro-Hunter)0.663Sierria
      0.308110Round Nose (Pro-Hunter)0.663Sierria
      0.308110Full Metal Jacket0.668Hornady
      0.308110Round Nose TMJ 30 Carbine0.676Speer
      0.308110Round Nose0.680Hornady
      0.308125HP/FN (Pro-Hunter)0.725Sierria
      0.308110Hollow Point (Varminter)0.795Sierria
      0.308110Spire SP0.804Speer
      0.308110Spire Point0.827Hornady
      0.308130Flat Nose SP/cann 30-30 Win0.829Speer
      0.308130Hollow Point0.860Speer
      0.308125Spitzer (Pro-Hunter)0.879Sierria
      0.308123Full Metal Jacket0.892Lapua
      0.308123Full Metal Jacket Cutting Edge0.892Lapua
      0.308123Spitzer0.892Lapua
      0.308150Round Nose (Pro-Hunter)0.895Sierria
      0.308150Round Nose0.905Hornady
      0.308150Flat Nose (Pro-Hunter)0.907Sierria
      0.308100HP Cutting Edge0.912Lapua
      0.308100HV0.920GS Custom Bullets
      0.308110Varmageddon FB Tipped0.920Nosler
      0.308125TNT™ HP0.920Speer
      0.308150Flat Nose SP/cann 30-30 Win0.920Speer

      Using the same as above for velocity and SG factor ( Max Length of .880″) but changing to a 1-18″ twist;
      Caliber weight Description Length Plastic tip length Manufacture

      0.30885Round Nose (Sports Master)0.535Sierria
      0.308100Short Jacket0.562Hornady
      0.308110Round Nose SP 30 Carbine0.602Speer
      0.308110Hollow Point0.614Speer
      0.308110Full Metal Jacket (Pro-Hunter)0.663Sierria
      0.308110Round Nose (Pro-Hunter)0.663Sierria
      0.308110Full Metal Jacket0.668Hornady
      0.308110Round Nose TMJ 30 Carbine0.676Speer
      0.308110Round Nose0.680Hornady
      0.308125HP/FN (Pro-Hunter)0.725Sierria
      0.308110Hollow Point (Varminter)0.795Sierria
      0.308110Spire SP0.804Speer
      0.308110Spire Point0.827Hornady
      0.308130Flat Nose SP/cann 30-30 Win0.829Speer
      0.308130Hollow Point0.860Speer
      0.308125Spitzer (Pro-Hunter)0.879Sierria

      Please bear in mind this chart is NOT a indicator of accuracy………………………. but stability ONLY

    • #27699
      Sgt. Mike
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      2900 fps as the model according to the charts the following bullets should produce stability giving a Miller SG of 1.4 or better as the temps go up (this was calculated at 59 degrees) so does the stability factor, same as length short = higher SG Factor = better stability :
      1-14″ Twist the following bullets should produce stability giving a Miller SG of 1.4 or better at 59 degrees (1.060″ Max Length)
      Caliber weight description length Plastic Tip length Manufacture

      0.30885Round Nose (Sports Master)0.535Sierria
      0.308100Short Jacket0.562Hornady
      0.308110Round Nose SP 30 Carbine0.602Speer
      0.308110Hollow Point0.614Speer
      0.308110Full Metal Jacket (Pro-Hunter)0.663Sierria
      0.308110Round Nose (Pro-Hunter)0.663Sierria
      0.308110Full Metal Jacket0.668Hornady
      0.308110Round Nose TMJ 30 Carbine0.676Speer
      0.308110Round Nose0.680Hornady
      0.308125HP/FN (Pro-Hunter)0.725Sierria
      0.308110Hollow Point (Varminter)0.795Sierria
      0.308110Spire SP0.804Speer
      0.308110Spire Point0.827Hornady
      0.308130Flat Nose SP/cann 30-30 Win0.829Speer
      0.308130Hollow Point0.860Speer
      0.308125Spitzer (Pro-Hunter)0.879Sierria
      0.308123Full Metal Jacket0.892Lapua
      0.308123Full Metal Jacket Cutting Edge0.892Lapua
      0.308123Spitzer0.892Lapua
      0.308150Round Nose (Pro-Hunter)0.895Sierria
      0.308150Round Nose0.905Hornady
      0.308150Flat Nose (Pro-Hunter)0.907Sierria
      0.308100HP Cutting Edge0.912Lapua
      0.308100HV0.920GS Custom Bullets
      0.308110Varmageddon FB Tipped0.920Nosler
      0.308125TNT™ HP0.920Speer
      0.308150Flat Nose SP/cann 30-30 Win0.920Speer
      0.308110V-Max0.926Hornady
      0.308110Match Target FB0.938Berger
      0.308115Match Target FB0.942Berger
      0.308150Mega0.943Lapua
      0.308100X Flat Nose0.945Barnes
      0.308150Mag-Tip SP0.965Speer
      0.308135Spitzer – Single Shot Pistol (Pro-Hunter)0.967Sierria
      0.308110Flat Base0.971ALCO
      0.308170Flat Nose (Pro-Hunter)0.996Sierria
      0.308170InterLock® Flat Point1.002Hornady
      0.308107SP1.010GS Custom Bullets
      0.308150Grand Slam™ SP1.020Speer
      0.308125Match Target FB1.026Berger
      0.308125SST®1.029Hornady
      0.308170Partition™ Round Nose1.030Nosler
      0.308125Flat Base1.037ALCO
      0.308110Tipped Triple-Shock™ X Flat Base1.047Barnes
      0.308150X Flat Nose1.060Barnes
      0.308145HV1.060GS Custom Bullets
      0.308125Ballistic Tip™ Spitzer1.060Nosler

      Notice that we only picked up .010″ in length for 200 FPS faster in the 1-14″ twist

      1-16″ Twist the following bullets should produce stability giving a Miller SG of 1.4 or better at 59 degrees (.970″ Max Length)
      Caliber weight description length Plastic Tip length Manufacture

      0.30885Round Nose (Sports Master)0.535Sierria
      0.308100Short Jacket0.562Hornady
      0.308110Round Nose SP 30 Carbine0.602Speer
      0.308110Hollow Point0.614Speer
      0.308110Full Metal Jacket (Pro-Hunter)0.663Sierria
      0.308110Round Nose (Pro-Hunter)0.663Sierria
      0.308110Full Metal Jacket0.668Hornady
      0.308110Round Nose TMJ 30 Carbine0.676Speer
      0.308110Round Nose0.680Hornady
      0.308125HP/FN (Pro-Hunter)0.725Sierria
      0.308110Hollow Point (Varminter)0.795Sierria
      0.308110Spire SP0.804Speer
      0.308110Spire Point0.827Hornady
      0.308130Flat Nose SP/cann 30-30 Win0.829Speer
      0.308130Hollow Point0.860Speer
      0.308125Spitzer (Pro-Hunter)0.879Sierria
      0.308123Full Metal Jacket0.892Lapua
      0.308123Full Metal Jacket Cutting Edge0.892Lapua
      0.308123Spitzer0.892Lapua
      0.308150Round Nose (Pro-Hunter)0.895Sierria
      0.308150Round Nose0.905Hornady
      0.308150Flat Nose (Pro-Hunter)0.907Sierria
      0.308100HP Cutting Edge0.912Lapua
      0.308100HV0.920GS Custom Bullets
      0.308110Varmageddon FB Tipped0.920Nosler
      0.308125TNT™ HP0.920Speer
      0.308150Flat Nose SP/cann 30-30 Win0.920Speer
      0.308110V-Max0.926Hornady
      0.308110Match Target FB0.938Berger
      0.308115Match Target FB0.942Berger
      0.308150Mega0.943Lapua
      0.308100X Flat Nose0.945Barnes
      0.308150Mag-Tip SP0.965Speer
      0.308135Spitzer – Single Shot Pistol (Pro-Hunter)0.967Sierria

      Again Notice .010″ for 200 FPS

      1-17″ Twist the following bullets should produce stability giving a Miller SG of 1.4 or better at 59 degrees (.935″ Max Length)
      Caliber weight description length Plastic Tip length Manufacture

      0.30885Round Nose (Sports Master)0.535Sierria
      0.308100Short Jacket0.562Hornady
      0.308110Round Nose SP 30 Carbine0.602Speer
      0.308110Hollow Point0.614Speer
      0.308110Full Metal Jacket (Pro-Hunter)0.663Sierria
      0.308110Round Nose (Pro-Hunter)0.663Sierria
      0.308110Full Metal Jacket0.668Hornady
      0.308110Round Nose TMJ 30 Carbine0.676Speer
      0.308110Round Nose0.680Hornady
      0.308125HP/FN (Pro-Hunter)0.725Sierria
      0.308110Hollow Point (Varminter)0.795Sierria
      0.308110Spire SP0.804Speer
      0.308110Spire Point0.827Hornady
      0.308130Flat Nose SP/cann 30-30 Win0.829Speer
      0.308130Hollow Point0.860Speer
      0.308125Spitzer (Pro-Hunter)0.879Sierria
      0.308123Full Metal Jacket0.892Lapua
      0.308123Full Metal Jacket Cutting Edge0.892Lapua
      0.308123Spitzer0.892Lapua
      0.308150Round Nose (Pro-Hunter)0.895Sierria
      0.308150Round Nose0.905Hornady
      0.308150Flat Nose (Pro-Hunter)0.907Sierria
      0.308100HP Cutting Edge0.912Lapua
      0.308100HV0.920GS Custom Bullets
      0.308110Varmageddon FB Tipped0.920Nosler
      0.308125TNT™ HP0.920Speer
      0.308150Flat Nose SP/cann 30-30 Win0.920Speer
      0.308110V-Max0.926Hornady

      1-18″ Twist ( Max Length of .890″) ;
      Caliber weight Description Length Plastic tip length Manufacture

      0.30885Round Nose (Sports Master)0.535Sierria
      0.308100Short Jacket0.562Hornady
      0.308110Round Nose SP 30 Carbine0.602Speer
      0.308110Hollow Point0.614Speer
      0.308110Full Metal Jacket (Pro-Hunter)0.663Sierria
      0.308110Round Nose (Pro-Hunter)0.663Sierria
      0.308110Full Metal Jacket0.668Hornady
      0.308110Round Nose TMJ 30 Carbine0.676Speer
      0.308110Round Nose0.680Hornady
      0.308125HP/FN (Pro-Hunter)0.725Sierria
      0.308110Hollow Point (Varminter)0.795Sierria
      0.308110Spire SP0.804Speer
      0.308110Spire Point0.827Hornady
      0.308130Flat Nose SP/cann 30-30 Win0.829Speer
      0.308130Hollow Point0.860Speer
      0.308125Spitzer (Pro-Hunter)0.879Sierria

    • #27700
      Sgt. Mike
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      So what about full summer shooting at say of 80 degrees?
      1-14″ twist at 2700 fps max length is 1.070″ ……… at 2900 fps max length is 1.080″
      1-16″ twist at 2700 fps max length is 0.975″ ……… at 2900 fps max length is 0.982″
      1-17″ twist at 2700 fps max length is 0.934″ ……… at 2900 fps max length is 0.940″
      1-18″ twist at 2700 fps max length is 0.895″ ……… at 2900 fps max length is 0.904″

      Just a tidbit of more information Standard atmosphere is defined as (per the US Army Labs)

      Altitude:Sea Level
      Barometric Pressure:750 mm Hg = 29.53 inches Hg
      Temperature:59°F = 15°C
      Relative Humidity:78 percent

      Bottom Line if I was recommending to a shooter I would use the set standard that the Military uses which I referred to in the first two posts in bullet and twist combination… hopefully this helps some while I know some will screw their head to the side and go HUH???? and then maybe they will have that lightbulb moment. But I think some will see why they can shoot some bullets in the summer yet not in the winter.
      If one is studious I did Not reference weight only length, as is evident weights are all over the place because of being flat based and or round nosed producing a shorter bullet.

      I used JBM Ballistics calculator for this as I am not a fan of Bergers version as it seems that Berger likes to overspin and is designed specifically for Boat tails. Hence I don’t use their model. This last part of calculator is a preference on my part if you like and use Berger’s version, I would say use it but rbear in mind berger uses a little longer bullets than majority of manufacturers

    • #27702
      bjornb
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      Great list sarge! I’ll be copying it to a Word file and printing it out. Thanks.

    • #27717
      Sgt. Mike
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      Played some with the Numbers on a 1-13″ twist using the Barnes Tipped Triple shock X Flat base — AAC BLK OUT bullet this puppy is 1.047″ long
      The SG is 1.537 @ 3100 fps which the 30-06 can reach with ease

      Trajectory Card
      Manufacturer:BarnesDescription:300 Tipped Triple-Shock™ X Flat Base – AAC BLKCaliber/Weight:0.308 in/110.0 gr
      Zero Range:200 ydZero Temperature:59.0 °FZero Altitude:0.0 ft
      Zero Height:0.00 inZero Offset:0.00 inZero Wind Speed:0.0 mph
      Zero Wind Angle:90 deg
      Sight Height:1.50 inSight Offset:0.00 inLine Of Sight Angle:0.0 deg
      Cant Angle:0.0 degWind Speed:10.0 mphWind Angle:90 deg
      Show Drop and Windage Deltas:NoWindage Correction for Zero Range:Yes
      Drop Units:1.000 MOAWindage Units:1.000 MOA
      Target Relative Drops:YesRound Output to Whole Numbers:Yes
      1500 ft
      Range (yd)59 °F65 °FRange (yd)
      10022100
      Spin Drift 1Spin Drift 1
      20000200
      Spin Drift 2Spin Drift 2
      300-2-2300
      Spin Drift 3Spin Drift 3
      400-6-5400
      Spin Drift 5Spin Drift 5
      500-9-8500
      Spin Drift 6Spin Drift 6
      600-14-13600
      Spin Drift 8Spin Drift 8
      700-20-18700
      Spin Drift 10Spin Drift 10
      800-27-25800
      Spin Drift 13Spin Drift 12
      1000-46-421000
      Spin Drift 17Spin Drift 17

      What about a 1-14″ Twist ?
      My SG will be 1.325 at 59 degrees
      but let’s look at trajectory

      Trajectory Card
      Manufacturer:BarnesDescription:300 Tipped Triple-Shock™ X Flat Base – AAC BLKCaliber/Weight:0.308 in/110.0 gr
      Zero Range:200 ydZero Temperature:59.0 °FZero Altitude:0.0 ft
      Zero Height:0.00 inZero Offset:0.00 inZero Wind Speed:0.0 mph
      Zero Wind Angle:90 deg
      Sight Height:1.50 inSight Offset:0.00 inLine Of Sight Angle:0.0 deg
      Cant Angle:0.0 degWind Speed:10.0 mphWind Angle:90 deg
      Show Drop and Windage Deltas:NoWindage Correction for Zero Range:Yes
      Drop Units:1.000 MOAWindage Units:1.000 MOA
      Target Relative Drops:YesRound Output to Whole Numbers:Yes
      1500 ft
      Range (yd)59 °F65 °FRange (yd)
      10022100
      Spin Drift 1Spin Drift 1
      20000200
      Spin Drift 2Spin Drift 2
      300-2-2300
      Spin Drift 3Spin Drift 3
      400-6-5400
      Spin Drift 5Spin Drift 5
      500-9-8500
      Spin Drift 6Spin Drift 6
      600-14-13600
      Spin Drift 8Spin Drift 8
      700-20-18700
      Spin Drift 10Spin Drift 10
      800-27-25800
      Spin Drift 13Spin Drift 12
      1000-46-421000
      Spin Drift 17Spin Drift 16

      See what happens with the Spin drift at 65 degrees with a 1 inch difference in twist
      Now lets look at a Palma bullet the Sierria 155gr 9Bullet Length is 1.131″ and a boat tail now normall the 30-06 will not get exactly 3100 fps but for comparisons sake let’s use that speed anyway.

      I get a SG of 1.738
      Trajectory is:

      Trajectory Card
      Manufacturer:SierraDescription:Palma [2155] (Litz)Caliber/Weight:0.308 in/155.0 gr
      Zero Range:200 ydZero Temperature:59.0 °FZero Altitude:0.0 ft
      Zero Height:0.00 inZero Offset:0.00 inZero Wind Speed:0.0 mph
      Zero Wind Angle:90 deg
      Sight Height:1.50 inSight Offset:0.00 inLine Of Sight Angle:0.0 deg
      Cant Angle:0.0 degWind Speed:10.0 mphWind Angle:90 deg
      Show Drop and Windage Deltas:NoWindage Correction for Zero Range:Yes
      Drop Units:1.000 MOAWindage Units:1.000 MOA
      Target Relative Drops:YesRound Output to Whole Numbers:Yes
      1500 ft
      Range (yd)59 °F65 °FRange (yd)
      10012100
      Spin Drift 1Spin Drift 1
      20000200
      Spin Drift 1Spin Drift 1
      300-2-2300
      Spin Drift 2Spin Drift 2
      400-5-4400
      Spin Drift 3Spin Drift 3
      500-8-7500
      Spin Drift 4Spin Drift 4
      600-11-10600
      Spin Drift 5Spin Drift 5
      700-15-13700
      Spin Drift 6Spin Drift 6
      800-19-17800
      Spin Drift 7Spin Drift 7
      1000-29-271000
      Spin Drift 10Spin Drift 10

      If one really looks at the charts above one notice the 110 Barnes and the Seirria 155 is sorta close in drop and spin drift to the 600 which the Flat base still shoot well but what happens with say a 110 gr Sierria Varmiter FB Legth is 0.795″ in the 13 twist
      our SG now jumps to 3.316

      Trajectory Card
      Manufacturer:SierraDescription:Hollow Point (Varminter)Caliber/Weight:0.308 in/110.0 gr
      Zero Range:200 ydZero Temperature:59.0 °FZero Altitude:0.0 ft
      Zero Height:0.00 inZero Offset:0.00 inZero Wind Speed:0.0 mph
      Zero Wind Angle:90 deg
      Sight Height:1.50 inSight Offset:0.00 inLine Of Sight Angle:0.0 deg
      Cant Angle:0.0 degWind Speed:10.0 mphWind Angle:90 deg
      Show Drop and Windage Deltas:NoWindage Correction for Zero Range:Yes
      Drop Units:1.000 MOAWindage Units:1.000 MOA
      Target Relative Drops:YesRound Output to Whole Numbers:No
      1500 ft
      Range (yd)59 °F65 °FRange (yd)
      1002.02.1100
      Spin Drift 1.5Spin Drift 1.5
      2000.10.4200
      Spin Drift 3.5Spin Drift 3.3
      300-3.2-2.6300
      Spin Drift 5.8Spin Drift 5.6
      400-7.6-6.8400
      Spin Drift 8.5Spin Drift 8.2
      500-13.7-12.4500
      Spin Drift 11.6Spin Drift 11.2
      600-21.6-19.9600
      Spin Drift 14.9Spin Drift 14.5
      700-31.7-29.5700
      Spin Drift 18.2Spin Drift 17.7
      800-43.9-41.1800
      Spin Drift 21.3Spin Drift 20.9
      1000-74.6-70.61000
      Spin Drift 27.3Spin Drift 26.9

      same bullet in a 1-10″ twist
      gives a SG of 5.604
      a Trajectory of

      Trajectory Card
      Manufacturer:SierraDescription:Hollow Point (Varminter)Caliber/Weight:0.308 in/110.0 gr
      Zero Range:200 ydZero Temperature:59.0 °FZero Altitude:0.0 ft
      Zero Height:0.00 inZero Offset:0.00 inZero Wind Speed:0.0 mph
      Zero Wind Angle:90 deg
      Sight Height:1.50 inSight Offset:0.00 inLine Of Sight Angle:0.0 deg
      Cant Angle:0.0 degWind Speed:10.0 mphWind Angle:90 deg
      Show Drop and Windage Deltas:NoWindage Correction for Zero Range:Yes
      Drop Units:1.000 MOAWindage Units:1.000 MOA
      Target Relative Drops:YesRound Output to Whole Numbers:No
      1500 ft
      Range (yd)59 °F65 °FRange (yd)
      1002.02.1100
      Spin Drift 1.5Spin Drift 1.4
      2000.10.4200
      Spin Drift 3.5Spin Drift 3.3
      300-3.2-2.6300
      Spin Drift 5.8Spin Drift 5.6
      400-7.6-6.8400
      Spin Drift 8.7Spin Drift 8.3
      500-13.7-12.4500
      Spin Drift 11.9Spin Drift 11.5
      600-21.6-19.9600
      Spin Drift 15.4Spin Drift 14.9
      700-31.7-29.5700
      Spin Drift 18.8Spin Drift 18.3
      800-43.9-41.1800
      Spin Drift 22.2Spin Drift 21.7
      1000-74.6-70.61000
      Spin Drift 28.7Spin Drift 28.2

      This should clearly demonstrate overspin (per JBM Ballistics website “It (SG) should be between 1.3 and 2.0 to ensure stabilty (the military uses 1.5”)

      Hopefully this answers why the shot goes left or right when shooting at a longer distance than the zero distance with no wind.

    • #27749
      Sgt. Mike
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      Bjorn give this a glance over for the HBN coating we was discussing offline
      http://www.bench-talk.com/articles/benchrest/163.html

    • #27890
      Sgt. Mike
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      OK I had thoughts of doing a Varmint / Cast only 30-06 1-17″ twist

      Load data information note this is the bottom side of the online information with Hodgdon
      125gr bullet.

      Yes I’ll be the first to admit that a better, or more efficient caliber would be possibly a 30 BR aka .308×1.5. But something can be said for not having to add extra Brass, dies etc etc

      Win748 @ 51grs – 3061fps (24″ BBL) powder = 3.34cc from VMD = 76% case Load Capacity
      Benchmark @51.5grs – 3242 (24″ BBL) powder = 3.69cc from VMD = 83% case Load Capacity
      IMR 8208XBR @ 51.5grs – 3100fps (24″ BBL) powder = 3.66cc from VMD = 84% case Load Capacity
      IMR 3031 @49.0grs – 3091 (24″ BBL) powder = 3.74cc from VMD = 85% case Load Capacity

      A 30-06 Case holds approx. 68.2 gr H2O divide by 15.432grs (1gr water = 1gram or 15.432grs) = 4.42cc’s

      Let’s figure on a bullet that is .925″ long
      Stability

      Stability
      Input Data
      Caliber: 0.308 in Bullet Weight: 125.0 gr
      Bullet Length: 0.925 in Plastic Tip Length: 0.000 in
      Muzzle Velocity: 3000.0 ft/s Barrel Twist: 17.0 in
      Temperature: 59.0 °F Pressure: 29.92 in Hg
      Output Data
      Stability: 1.433

      18-May-16 14:59, JBM/jbmstab-5.1.cgi

      Trajectory Card now that .925″ length bullet lets change that to a .879″ length and keep the 125 grs weight
      the stability at the Muzzle changes to 1.652 (SG) notice the ONLY thing changed is the length

      Trajectory
      Input Data
      Manufacturer: Sierra Description: Spitzer (Pro-Hunter)
      Caliber: 0.308 in Weight: 125.0 gr
      Ballistic Coefficients: 0.265 [0-2000], 0.277 [2000-2800], 0.279 [2800-5000] G1 (ASM)
      Bullet Length (Library): 0.879 in Plastic Tip Length: 0.000 in
      Muzzle Velocity: 3000.0 ft/s Distance to Chronograph: 10.0 ft
      Sight Height: 1.50 in Sight Offset: 0.00 in
      Zero Height: 0.00 in Zero Offset: 0.00 in
      Windage: 0.000 MOA Elevation: 0.000 MOA
      Line Of Sight Angle: 0.0 deg Cant Angle: 0.0 deg
      Barrel Twist: 17.0 in Twist Direction: Right
      Wind Speed: 0.0 mph Wind Angle: 90.0 deg
      Target Speed: 10.0 mph Target Angle: 90.0 deg
      Target Height: 12.0 in
      Temperature: 59.0 °F Pressure: 29.92 in Hg
      Humidity: 0 % Altitude: 0.0 ft
      Vital Zone Radius: 5.0 in
      Std. Atmosphere at Altitude: No Pressure is Corrected: Yes
      Zero at Max. Point Blank Range: No Target Relative Drops: Yes
      Mark Sound Barrier Crossing: No Include Extra Rows: No
      Column 1 Units: 1.00 in Column 2 Units: 1.00 MOA
      Round Output to Whole Numbers: No
      Output Data
      Elevation: 3.419 MOA Windage: 0.000 MOA
      Atmospheric Density: 0.07647 lb/ft³ Speed of Sound: 1116.4 ft/s
      Maximum PBR: 333 yd Maximum PBR Zero: 285 yd
      Range of Maximum Height: 161 yd Energy at Maximum PBR: 1046.1 ft•lbs
      Sectional Density: 0.188 lb/in² Stability at Muzzle: 1.652

      Calculated Table
      Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead
      (yd) (in) (MOA) (in) (MOA) (ft/s) (none) (ft•lbs) (s) (in) (MOA)
      0 -1.5 *** 0.0 *** 3012.1 2.698 2517.7 0.000 0.0 ***
      100 -0.0 -0.0 0.1 0.1 2663.5 2.386 1968.7 0.106 18.6 17.8
      200 -3.4 -1.6 0.2 0.1 2339.2 2.095 1518.5 0.226 39.8 19.0
      300 -13.3 -4.2 0.6 0.2 2038.2 1.826 1152.9 0.364 64.0 20.4
      400 -31.5 -7.5 1.1 0.3 1751.3 1.569 851.1 0.522 91.9 21.9
      500 -61.2 -11.7 1.9 0.4 1494.8 1.339 620.0 0.708 124.6 23.8
      600 -106.6 -17.0 3.1 0.5 1280.1 1.147 454.7 0.925 162.8 25.9

      18-May-16 15:49, JBM/jbmtraj_drift-5.1.cgi

      Notice that I zeroed out the wind the amount of wind age is the induced by spin drift that is induced by the twist rate, it is normally automatically calculated into the windage tables that one runs from the online sources which will be hidden in the tables.

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