Range Adjustment .17HMR

[Axe]

Following a post on RFC, I sat down and worked out some figures on the number of clicks that would be required to dial in the range on a 1/4moa scope on a .17HMR.

 

The figures are based on a scope height of 1.75 from centre of the bore and a zero of 100yards. Since up to 100 yards you dont really need it, I worked the figures from 110yards in 10 yard increments to 200yards.

 

The yardage is shown with the suggested number of clicks and the amount of deviation you get from centre i.e. distance of impact from the cross hair.

 

Yards Clicks Deviation/inch/

110____1____.045

120____2____.03

130____3____.035

140____4____.17

150____6____.01

160____8____.16

170____9____.135

180____11___.05

190____13___.025

200____15___.06

 

These are currently untested so I would appreciate if the mathmatical genius amongst us could check me on this. I used point blank for the figures with 2600fps and a BC of .125.

 

Regards,

 

Axe.

[Graham M]

And with a 16 inch barrel they are........................

G.M.

[dunganick]

this is also assuming that your clicks are actually 1/4" or 1/4MOA as most cheap scopes which alot of us use on rimfires dont actually give as much adjustment as they say they do and the clicks are not actually the said distances

[Axe]

I think you need to test your own gun really, these figures dont quite stack up for me and are around an inch out. I have also run pointblank simulations and found them to be very accurate but im not entirely convinced myself that 0.125 is the correct B.C. for the bullet myself. Nick is right to point out that most cheap scopes are not accurate enough for this to work for everyone, even if these figures do match their gun.

 

Perhaps if you post your comparitive figures we can compare. However, the BC is correct as published by Federal Cartridge. Try running the same load data and scope height in PB and see what you get.

 

This is the exported text from PB, unfortunately it only allows 25 yard increments on exported data.:

 

Load Data

~~~~~~~~~

 

Name: 17 Cal, , 17 grn

Ballistic Coeff: 0.125

Bullet Weight: 17

Velocity: 2600

Target Distance: 100

Scope Height: 1.800

Temperature: 70

Altitude: 300

 

Ballistic Data

~~~~~~~~~~~~~~~

Range Elevation Velocity Energy ETA Drop Max Y 10mph Wind Deflect

0 yds -1.80 in 2600 fps 255 fpe 0.000 sec 0.00 in -1.80 in -0.00 in

25 yds -0.74 in 2431 fps 223 fpe 0.030 sec 0.17 in -0.68 in 0.15 in

50 yds -0.05 in 2269 fps 194 fpe 0.062 sec 0.70 in -0.54 in 0.70 in

75 yds 0.21 in 2113 fps 168 fpe 0.096 sec 1.66 in -0.27 in 1.68 in

100 yds 0.00 in 1962 fps 145 fpe 0.133 sec 3.10 in 0.14 in 3.06 in

125 yds -0.77 in 1819 fps 125 fpe 0.172 sec 5.10 in 0.72 in 4.94 in

150 yds -2.24 in 1684 fps 107 fpe 0.216 sec 7.80 in 1.54 in 7.47 in

175 yds -4.46 in 1557 fps 91 fpe 0.262 sec 11.25 in 2.61 in 10.56 in

200 yds -7.56 in 1438 fps 78 fpe 0.312 sec 15.57 in 4.00 in 14.25 in

225 yds -11.78 in 1332 fps 67 fpe 0.366 sec 21.02 in 5.80 in 18.76 in

250 yds -17.23 in 1237 fps 58 fpe 0.425 sec 27.68 in 8.04 in 23.95 in

275 yds -24.15 in 1158 fps 51 fpe 0.487 sec 35.83 in 10.82 in 29.92 in

300 yds -32.72 in 1092 fps 45 fpe 0.554 sec 45.63 in 14.20 in 36.58 in

325 yds -43.12 in 1041 fps 41 fpe 0.624 sec 57.26 in 18.23 in 43.89 in

350 yds -55.48 in 998 fps 38 fpe 0.698 sec 70.84 in 22.96 in 51.79 in

375 yds -69.85 in 961 fps 35 fpe 0.775 sec 86.44 in 28.44 in 60.17 in

400 yds -86.47 in 929 fps 33 fpe 0.854 sec 104.29 in 34.74 in 69.10 in

425 yds -105.27 in 900 fps 31 fpe 0.936 sec 124.31 in 41.85 in 78.42 in

450 yds -126.51 in 874 fps 29 fpe 1.020 sec 146.78 in 49.89 in 88.21 in

475 yds -150.36 in 849 fps 27 fpe 1.108 sec 171.86 in 58.91 in 98.49 in

500 yds -176.90 in 826 fps 26 fpe 1.197 sec 199.62 in 68.96 in 109.20 in

525 yds -206.12 in 805 fps 24 fpe 1.289 sec 230.06 in 80.04 in 120.27 in

550 yds -238.28 in 784 fps 23 fpe 1.383 sec 263.45 in 92.27 in 131.76 in

575 yds -273.70 in 764 fps 22 fpe 1.480 sec 300.10 in 105.77 in 143.76 in

600 yds -312.53 in 745 fps 21 fpe 1.580 sec 340.16 in 120.60 in 156.23 in

625 yds -354.81 in 727 fps 20 fpe 1.682 sec 383.66 in 136.80 in 169.14 in

650 yds -400.58 in 709 fps 19 fpe 1.787 sec 430.65 in 154.40 in 182.43 in

675 yds -449.90 in 692 fps 18 fpe 1.893 sec 481.20 in 173.43 in 196.08 in

700 yds -503.46 in 676 fps 17 fpe 2.002 sec 535.98 in 194.16 in 210.28 in

725 yds -561.53 in 659 fps 16 fpe 2.115 sec 595.29 in 216.70 in 225.03 in

750 yds -624.21 in 644 fps 16 fpe 2.231 sec 659.19 in 241.11 in 240.30 in

775 yds -691.57 in 628 fps 15 fpe 2.349 sec 727.77 in 267.44 in 256.04 in

800 yds -763.67 in 613 fps 14 fpe 2.470 sec 801.10 in 295.73 in 272.22 in

[Dunkield]

All seems a bit technical to me . .

If it's a long way off, I just aim a bit higher

[Axe]

All seems a bit technical to me . .

If it's a long way off, I just aim a bit higher

 

 

If its a long way off, I usually walk closer.

[Axe]

Just at the moment, I can honestly say I havent seen any variance in the Remmingtons I am using. Nor did I see a variance in Federal Cartridge. Since all the makes are manufactured by CCI you expect them all to suffer equally. I havent used Hornady but have heard very good reports of it. I'm quite looking forward to getting my hands on some Sellier & Bellot .17HMR V-Max.