hmm maths has annoyed me

[Jackmanuk]

ok so iv spent the last 4 hours doing a range card .....its my first one and i cant guaranty bullet speed but some research I reckon it should be close

there are also some idiot maths at the end to help ......me

note the last line

Range Drop Velocity Energy Momentum Time Elevation 1x Click (SCI) Required Clicks
(Yards) (Inches) (ft/sec) (ft-lbs) (lb-sec) (Secs) (MOA) (0.25 MOA Per 100 yards) (Rounded)

0 -1.50 2700.0 2508.9 1.8584 0.000 -----
100 0.00 2519.1 2184.0 1.7339 0.115 0.00 0.25 0
200 -3.99 2345.4 1893.1 1.6143 0.239 -2.00 0.50 8
300 -14.31 2178.4 1633.2 1.4994 0.371 -4.77 0.75 19
400 -31.97 2018.3 1402.0 1.3892 0.514 -7.99 1.00 32
500 -58.19 1865.5 1197.7 1.2840 0.669 -11.64 1.25 46
600 -94.42 1720.6 1018.8 1.1843 0.837 -15.74 1.50 62
700 -142.42 1584.6 864.1 1.0907 1.018 -20.35 1.75 81
800 -204.29 1458.7 732.3 1.0041 1.216 -25.54 2.00 102
900 -282.55 1344.7 622.3 0.9256 1.430 -31.39 2.25 113
1000 -380.06 1244.3 532.8 0.8564 1.663 -38.01 2.50 152
1100 -500.07 1159.4 462.6 0.7980 1.913 -45.46 2.75 182
1200 -645.96 1090.9 409.6 0.7509 2.180 -53.83 3.00 215


For a 100 yard zero but a 200 yard Range zero : +2.00 moa (8 clicks) +


Scope Crosshair Increment (SCI): The Crosshair movement within the scope to adjust point of impact (Zero)

Click: Scope Crosshair Increment (SCI) 1/4 MOA Per 100 Yards
0.25 x (Range / 100) = Click (SCI)
0.25 x (1100 Yards = 11) = 2.75

For scopes With SCI of 1/8 Per 100 yards Click Value is HALVED and Required Clicks is DOUBLED In Table


To Work Out Clicks: Drop (Inches) / (Range / 100) = MOA Differance x Click (SCI)

For 1200 Yards: 1200 / 100= 12 645.96
/ 12
= 53.83 x 3 = 215 (Rounded)


Scope Adjustment Dial Numbering : 1 Full Revolution = 60 Clicks or 15 MOA @ 100 Yards

1 Full Revolution + 1 Click = 600 Yard

scope Zero Runs out at -33 MOA + 14 MOA .......bo...cks


so it seem my scope runs out of elevation at 33 Moa or how ever many clicks that is which means i cant shoot beyond 900 yards with a zero on scope ( i think)

but i do have 14 MOA to play with so in theory .......well my theory is that i could get 10 MOA Mounts which would change my range to - 43 and + 4 .......

still not 1200 yards but closer 20 moa would mean i cant zero at 100 yards and maxing my scope would leave me 6 inches above the crosshair tesnews


or are my meds simply getting the better of me today

[DW58]

wtfwtf Oh hell - I haven't done serious maths since 1975.

[Jackmanuk]

I was thinking the same thing when i was half way through

[DW58]

Thank goodness for the wealth of good ballistics apps/programs available.

[ovenpaa]

Hmm, well looking at a different way you need 14 minutes of incline to bring you to mechanical zero. With an assumed ring separation of 125,0mm 14 minutes would equate to a rear shim of around 0,51mm.

You will need around 40 minutes of elevation to get your .308 to 1200 on a warm day.

[Jackmanuk]

you say that but tried 2 programs one on pc and other on my phone and keeping both data exatly the same they were showing different results the pc program shows the 215 clicks i have in the prevous post the app shows 254 clicks at 1200 yards , all the rest is also different so its interesting but i think sticking with 1 and adjusting at hte range for hte ammo i use would be the best bet

[ovenpaa]

Assuming a conservative 3000fps with a 155 grain bullets. A 155 Scenar with a 100 yard zero is going to need 12 mils to get to 1200 yards. 12mils = 40.5 minutes

Hmm.. You are basing your 1200 on 2700 fps. It is not going to happen, that is 15,7 mils or 53 MOA, you are going to be around 1025fps at best and the bullet will wobbling all over the place. you have got to push the bullet quicker or look for a longer barrel.

[Jackmanuk]

Hmm, well looking at a different way you need 14 minutes of incline to bring you to mechanical zero. With an assumed ring separation of 125,0mm 14 minutes would equate to a rear shim of around 0,51mm.

You will need around 40 minutes of elevation to get your .308 to 1200 on a warm day.

my charts shows 53 but then it seems my rounds although painfull in the shoulder could be faster


the basis im working off is ( without a chrony)

hornaday 9th manual says 48.2 grains of the cfe223 in a 155 amax with a bc of .435 makes its 2700 fps out of a 22" 1-12" win 70 barrel

im only using 48 grains but my barrel is 26" 1-12 so i would say its close enough ...i will chrony it one day and hte 155 smk palma has a bc of 0.5 ( i saw somewhere)

apart from 50 rounds hurting and still hurting a day later there were no over pressure signs from the hornaday match brass and no powder residue aroudn the neck of the case unlike the 46 grains so its showing a good seal

the manual shows 49.6 grains as max to take the round to 2900 fps but i dont think il push that high



on a side note i tried my 200 grain subsonic loads which .... were subsonic , alittle to much air in the moderator causeing a high pitch air rush after fireing so maybe a tad less powder may help with that ..... didnt really check accuracy since at 600 yards they had a drop of about a field and was lucky to get one in the sand at all.. but at least they work

[Jackmanuk]

our next shoot is 100 yards so i think il take the chrony and doing to load dev see how 48, 48.5 49 , and maybe 49.5 act

[Chuck]

What language is this thread in??? sign85