Totseans

Tag: weapon

  • Sight Adjustments: A Comprehensive How-To

    Burn Ballistic Solutions ClickCal Public Alpha
     

    Code:
    ClrHome
:Output (3,1, Click Calculator)
:Output (4,1, Burn Ballistics)
:Output (5,1, Alpha Release) 
:Pause 
:ClrHome
:Lbl M
:Menu( Click Calculator,Click Calculator, A1,Conversions, A2 , About , A3, Exit, EX)
:ClrHome
:Lbl A1
:Menu( Adjustments,1/4 MOA, B1,1/8 MOA, B2 , Custom , B3, Back, M)
:Lbl B1
:Disp Range in yards
:Prompt R
:(((((R*36)*2)*π)/360)/60)→M
:(1/4)→C
:Disp Drop (Inches)
:Prompt D
:((M/(C))→V
:(D/V)→A
:Disp  A
:Clicks
:Pause
:ClrHome
:Goto A1
:Lbl B2
:Disp Range in yards
:Prompt R
:(((((R*36)*2)*π)/360)/60)→M
:(1/8)→C
:Disp Drop (Inches)
:Prompt D
:((M/(C))→V
:(D/V)→A
:Disp  A
:Clicks
:Pause
:ClrHome
:Goto A1
:Lbl B3
:Disp Range in yards
:Prompt R
:(((((R*36)*2)*π)/360)/60)→M
:Disp 1 click  and  100 yd
:Prompt C
:Disp Drop (Inches)
:Prompt D
:((M/(C))→V
:(D/V)→A
:Disp  A
:Clicks
:Pause
:ClrHome
:Goto A1
:Lbl A2
:Menu( Conversions,Yds. to M., C1,In. to Cm., C2 , M. to Yds. , C3, Cm to In.,C4, Back, M)
:Lbl C1
:ClrHome
:Disp How many yards
:Prompt Y
:(Y*0.9144)→M
:Output(4,2, M) 
:Output(5,2, Meters)
:Pause 
:
:ClrHome
:Goto A2
:Lbl C2
:ClrHome
:Disp How many inches
:Prompt I
:(I*2.54)→C
:Output(4,2, C) 
:Output(5,2, CenWebOffters)
:Pause 
:ClrHome
:Goto A2 
:Lbl C3
:ClrHome
:Disp How many meters
:Prompt M
:(M*1.0936133)→Y
:Output(4,2, Y) 
:Output(5,2, Meters)
:Pause 
:
:ClrHome
:Goto A2
:Lbl C4
:ClrHome
:Goto M
:Lbl A3
:Output (3,1, Click Calculator)
:Output (4,1, Version 1.0)
:Output (5,1, Burn Ballistics)
:Disp A different face
:Disp but the words 
:Disp never change....
:Pause 
:ClrHome
:Goto M

    This only calculates how many clicks you need at a specified range with a specified drop in inches (I threw a converter in there too for you european folks) It’s also alpha and buggy, but the public and full version that takes load data barrel length, wind clock angle, humidity, and all sorts of fun stuff hasn’t been released to the public.

    Calculating Minute of Angle

    To understand sight adjustments on rifles and accuracy of surveying instruments, you need to be able to calculate minute of angle (MOA). MOA is derived from simple geometry. I won’t bore you so here is the formula to calculate MOA at a specific range in yards:

    Code:
    (((((r*36)*2)*Pi)/360)/60)=M

r= range in yards

m= MOA

    Let’s break down the formula:

    Where does the 36 come from?

    36 is how many inches are in 1 yard. We work with inches because that is typically standard and 1 MOA is almost 1 inch @ 100 yards. Below is the conversion for you:

    Code:
    1 yd. *(3 ft./1 yd.)=3 ft.

3ft * (12 in./1 ft.)=36 in.

    Why multiply it by 2?

    We multiply the first part of the equation by two because we calculate MOA using the radius of a circle (1/2 of the diameter aka distance across the midesection of the circle)

    Why divide by 360?

    Because there are 360 degrees in one circle.

    Why divide by 60?

    Because there are 60 minutes of arc in one degree.

    EXAMPLES

    What does 4 MOA equal at 850 yards?

    Step 1: Recall the MOA formula:

    Code:
    (((((r*36)*2)*Pi)/360)/60)=M

r= range in yards

m= MOA

    Step 2: Plug in 850 for r:

    Code:
    (((((850*36)*2)*Pi)/360)/60)=M

    Step 3: Solve using order of operations:

    Code:
    (((((850*36)*2)*Pi)/360)/60)=M

((((30600)*2)*Pi)/360)/60)=M

(((6120)*Pi)/360)/60)=M

((192265.4704/360)/60)=M

(534.0707511/60)=M

M=8.901179185 in

    Step 4: Recall we wanted to know what 4 MOA was at 850 yards:

    Code:
     8.901179185*4=35.60471674 inches

    It’s obvious you would most likely round the answer to two decimal places.

    What does 1 MOA equal at 83 yards?

    Step 1: Recall the MOA formula:

    Code:
    (((((r*36)*2)*Pi)/360)/60)=M

r= range in yards

m= MOA

    Step 2: Plug in 83 for r:

    Code:
    (((((83*36)*2)*Pi)/360)/60)=M

    Step 3: Solve using order of operations:

    Code:
    (((((83*36)*2)*Pi)/360)/60)=M

((((2988)*2)*Pi)/360)/60)=M

(((5976)*Pi)/360)/60)=M

((18774.1577/360)/60)=M

(52.15043805/60)=M

M=0.8691739675 in

    Here are approximations of MOA at common ranges (100 yard intervals)

    Code:
    1 MOA @ 100 yards = 1 inch 
1 MOA @ 200 yards = 2 inches 
1 MOA @ 300 yards = 3 inches 
1 MOA @ 400 yards = 4 inches 
1 MOA @ 500 yards = 5 inches 
1 MOA @ 600 yards = 6 inches 
1 MOA @ 700 yards = 7 inches 
1 MOA @ 800 yards = 8 inches 
1 MOA @ 900 yards = 9 inches 
1 MOA @ 1000 yards = 10 inches
    Scope Adjustments 101

    This section is geared more towards weapons use, but depending on the instrument you can still use the same prinicipals.

    Adjusting your scope is a vital part shooting at long ranges. It is realy simple once you learn how to calculate MOA.

    Code:
    D/(M*C)=A

D= Drop (inches)

M= MOA at target distance

C= what one click is @ 100 yard on your scope

A= adjustment in clicks
    EXAMPLES

    We will use the previous examples from “Calculating Minute of Angle”.

    What does 1 click equal at 83 yards if your scope has 1/4 MOA adjustments @ 100 yards?

    Step 1: Calculate MOA

    Code:
    (((((83*36)*2)*Pi)/360)/60)=M

((((2988)*2)*Pi)/360)/60)=M

(((5976)*Pi)/360)/60)=M

((18774.1577/360)/60)=M

(52.15043805/60)=M

M=0.8691739675 in

    Step 2: Recall the Click formula

    Code:
    M*C

    Step 3: Plug in M and solve:

    Code:
    0.8691739675 in. * (1/4)=0.217275 in.

    What does 1 click equal at 850 yards if your scope has 1/8 MOA adjustments @ 100 yards?

    Step 1: Calculate MOA

    Code:
    (((((850*36)*2)*Pi)/360)/60)=M

((((30600)*2)*Pi)/360)/60)=M

(((6120)*Pi)/360)/60)=M

((192265.4704/360)/60)=M

(534.0707511/60)=M

M=8.901179185 in

    Step 2: Recall the Click formula

    Code:
    M*C

    Step 3: Plug in M and solve:

    Code:
    8.901179185 in * (1/8)=1.112647398 in.

    Most people round their answers to usable numbers.

    Scope Adjustments 102

    Once again this is more firearms related, but some survey insturments have adjustments in clicks.

    In the previous lessons you have learned how to calculate MOA and what 1 click on your scope equals at a given range. Now you get to put it all together.

    Recall the scope click formula:

    In Scope Adjustments 101 you learned the “M*C” part of the equation.

    EXAMPLES

    We will use the examples from scope adjustments 101:

    You are shooting high by 5 inches at 83 yards. Your scope has 1/4 MOA adjustments at 100 yards. How many clicks do you adjust your scope?

    Step 1: Calculate how many inches 1 click equals:

    Code:
    0.8691739675 in. * (1/4)=0.217275 in.

    Step 2: plug the answer into the Click formula:

    Code:
    5 in./0.217275 in = 23.01231159 clicks

    Step 3: Round the answer to the nearest whole number.

    Code:
    23 clicks

    Your bullet will drop 125 inches at 850 yards. Your scope has 1/8 MOA adjustments at 100 yards. How many clicks do you adjust your scope?

    Step 1: Calculate how many inches 1 click equals:

    Code:
    8.901179185 in * (1/8)=1.112647398 in.

    Step 2: plug the answer into the Click formula:

    Code:
    125 in / 1.112647398= 112.3446657

    Step 3: Round the answer to the nearest whole number.

    Code:
    112 clicks

    That’s it. You now know how to calculate MOA and adjustments for instruments that use clicks.

    Discuss http://www.totse.info/bbs/showthread.php?t=1190

  • UK Airgun Laws

    I see a lot of bullshit and misconception on the web regarding gun law, and specifically airgun law in the UK. A lot of people in the UK have never seen a gun IRL, let alone held or fired one.

    This is highlighted by members of the publics reactions to guns. A member of the public saw some one with a .22 rifle fitted with a scope. He described it to the press as ‘some huge James Bond sniper rifle with a telescope on it’. Hysteria much?

    As far as analagies go, that one ranks along ‘yeah man, a subaru imprezza is basically an F1 car’.

    Before I begin, I will say if you are unfamiliar with guns, get to know them. Get to know the people that use them recreationally – have a bit of understanding on what is what, why something is totally unsuitable in some situations and let real knowledge form your opinions.

    If you are on land you do not own, or do not have permission to shoot on with a loaded air rifle or an air rifle out of its bag or case, you can get done for armed tresspass. At all times when carrying an airrifle, you must have a legitimate reason for having it. Reasons would include travelling to or from a place where your are allowed to shoot, travelling to or from a place to purchase or sell the weapon, travelling to or from a place to have it repaired or modified.

    If you are on land wich you own or have permission to shoot on, you must not be in a posiion closer than 50ft to the centre of a public highway when you fire it.

    loaded in public – 6 months jail / £2500 fine
    armed tresspass – 3 months in jail / £2500 fine
    Having an air rifle intent to damage property – 10 years
    using an air rifle in a threatening manner – 10 years

    If you get sentanced to <3 years – 5 year ban on handling / owning a firearm
    If sentanced to >3 years – lifetime ban.

    If you shoot some one intentially – life
    If you shoot some one in an avoidable accident and kill – manslaughter

    These are all maximum sentances. You know what this country is like for guns now. When I was a kid, the police would normally not give a shit if you were shooting on public land, as long as you didnt look like you would cause a nuciance.

    Now, if you are seen with any gun in public, armed response will turn up. They should give you three warnings to put it down, but it ussually goes

    ‘ArmedPoliceDropTheWeapon,ArmedPoliceDropTheWeapon ,ArmedPoliceDropTheWeapon,’ Bang and you are dead.

    In answer to your question, no you do not need a licence unless the air rifle has a musle velocity of more than 12ft/lb. Anything with a musle velocity of over 1ft/lb is considered a fire arm.

    You will then want to know how powerful your air rifle is. For example, with a crossman power pellet (14.3 grains), my Weirauch HW77 .22 (lets say it will have a musle velocity of 600fps) will be producing 11.43 ft/lbs.

    If I used an air arms feild pellet (16.4 grains) I get 13.11 ft/lbs and become illegal. There will be a small drop in musle velocity, but only very small. Spin (left to right accuracy) and drop are effected more with a heavier pellet.

    If I use an Eley Magnum (30 grains) and use that same musle velocity, we get 23.99 ft/lbs. Nearly double to the legal limit, and most FAC air rifles in the UK market are in the range of 30 ft/lbs.

    Now, the police are not going to test your air rifle with the Eley magnum just to catch you out. Only an idiot would use them in a non FAC air rifle as you would just not hit the target.

    Now, say I am out with a tin of H&N Trophy Hunter in my pocket, at 15.4 grains, that gives me 12.31 ft/lbs, I am illegal. Having seen quite a few Police Inspector sample papers, I wouldnt risk that call back to the station if I had a brand and model of air rifle with me that would have info on, or looked like it could shoot at 600fps and a tin of branded pellets, within a few minutes even google could tell you what position I would be in.

    To calculate for your own air rifle

    Weight of Pellet in grains X (FPS squared) / 450240

    There is a magic number in all of this to keep you safe. If you can tune your air rifle to fire a projectile at 671 fps, the weight of the pellet in grains will give you the ft/lb exactly – eg, your pellet weights 12 grains, you have 12ft/lb. You dont get many pellets for a .22 (but quite a few for a .20) at 12 grains, but the Paragon Z2 is 12 grains.

    My advice is just shoot where you are allowed to shoot, only shoot things you are allowed to shoot and the police wont hasstle you too much. In some shooting comps tho, not only do they chronograph (measure musle velocity, a lot do) but the police will be there too.

    My local gun shop stickers the pellet tins with the average pellet weight in grains and I leave it on, in case anyone wants to know .

    Discuss http://www.totse.info/bbs/showthread.php?t=8979