{"id":71,"date":"2025-10-20T23:03:01","date_gmt":"2025-10-20T23:03:01","guid":{"rendered":"https:\/\/codnortargetandfieldclub.co.uk\/?page_id=71"},"modified":"2025-11-16T12:55:46","modified_gmt":"2025-11-16T12:55:46","slug":"calculators","status":"publish","type":"page","link":"https:\/\/codnortargetandfieldclub.co.uk\/index.php\/calculators\/","title":{"rendered":"Calculators"},"content":{"rendered":"\n<div id=\"bc-wrapper\" style=\"max-width:900px;margin:auto;background:#0b0b0b;color:#00b4ff;padding:20px;border-radius:10px;box-shadow:0 0 20px #00b4ff40;font-family:Orbitron,monospace;\">\n  <h2 style=\"text-align:center;\">Ballistic Calculator \u2014 RA4 Model (Full Visual Fix)<\/h2>\n\n  <!-- Input Form -->\n  <form id=\"bc-form\" style=\"display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:12px;margin-bottom:12px;\">\n    <label>Muzzle Velocity\n      <input type=\"number\" id=\"velocity\" placeholder=\"Enter value\">\n      <select id=\"velocity_unit\"><option value=\"mps\">m\/s<\/option><option value=\"fps\">ft\/s<\/option><\/select>\n    <\/label>\n\n    <label>Ballistic Coefficient (RA4)\n      <input type=\"number\" id=\"bc\" step=\"0.01\" placeholder=\"0.45\">\n    <\/label>\n\n    <label>Projectile Weight\n      <input type=\"number\" id=\"weight\" placeholder=\"Enter value\">\n      <select id=\"weight_unit\"><option value=\"gr\">gr<\/option><option value=\"g\">g<\/option><\/select>\n    <\/label>\n\n    <label>Range\n      <input type=\"number\" id=\"range\" placeholder=\"Enter value\">\n      <select id=\"range_unit\"><option value=\"m\">m<\/option><option value=\"yd\">yd<\/option><\/select>\n    <\/label>\n\n    <label>Zero Distance\n      <input type=\"number\" id=\"zero_range\" placeholder=\"Enter value\">\n      <select id=\"zero_unit\"><option value=\"m\">m<\/option><option value=\"yd\">yd<\/option><\/select>\n    <\/label>\n\n    <label>Scope Height\n      <input type=\"number\" id=\"scope_height\" placeholder=\"Enter value\">\n      <select id=\"scope_unit\"><option value=\"mm\">mm<\/option><option value=\"in\">in<\/option><\/select>\n    <\/label>\n\n    <label>Wind Speed\n      <input type=\"number\" id=\"wind\" placeholder=\"Enter value\">\n      <select id=\"wind_unit\"><option value=\"mps\">m\/s<\/option><option value=\"mph\">mph<\/option><\/select>\n    <\/label>\n\n    <label>Wind Direction (\u00b0)\n      <input type=\"number\" id=\"wind_angle\" placeholder=\"90\">\n    <\/label>\n\n    <label>Output Units\n      <select id=\"unit_type\"><option value=\"moa\">MOA<\/option><option value=\"mrad\">MRAD<\/option><\/select>\n    <\/label>\n\n    <label>Reticle Style\n      <select id=\"reticle_type\">\n        <option value=\"grid\">MOA Grid<\/option>\n        <option value=\"dots\">MRAD Dots<\/option>\n        <option value=\"bdc\">BDC Tree<\/option>\n      <\/select>\n    <\/label>\n\n    <label>Range Card Step\n      <input type=\"number\" id=\"range_step\" value=\"50\" min=\"10\">\n      <select id=\"step_unit\"><option value=\"m\">m<\/option><option value=\"yd\">yd<\/option><\/select>\n    <\/label>\n\n    <div style=\"grid-column:1\/-1;display:flex;gap:10px;justify-content:center;margin-top:10px;\">\n      <button type=\"button\" id=\"bc-run\" style=\"background:linear-gradient(90deg,#00b4ff,#0070ff);color:white;border:none;padding:8px 16px;border-radius:8px;cursor:pointer;\">Simulate<\/button>\n      <button type=\"button\" id=\"bc-toggle\" style=\"background:linear-gradient(90deg,#0070ff,#00b4ff);color:white;border:none;padding:8px 16px;border-radius:8px;cursor:pointer;\">Toggle Range Card<\/button>\n    <\/div>\n  <\/form>\n\n  <div id=\"bc-view\">\n    <div id=\"bc-canvas-container\" style=\"display:flex;justify-content:center;\">\n      <canvas id=\"bc-canvas\" height=\"500\" style=\"display:block;border:1px solid #00b4ff40;border-radius:10px;background:#111;width:100%;\"><\/canvas>\n    <\/div>\n    <table id=\"bc-table\" style=\"width:100%;border-collapse:collapse;display:none;margin-top:10px;text-align:center;\">\n      <thead><tr style=\"background:#00b4ff40;\"><th>Range<\/th><th>Drop<\/th><th>Drift<\/th><th>Energy<\/th><\/tr><\/thead>\n      <tbody id=\"bc-tbody\"><\/tbody>\n    <\/table>\n  <\/div>\n<\/div>\n\n<script>\n(function(){\n  const canvas=document.getElementById('bc-canvas');\n  const ctx=canvas.getContext('2d');\n  const table=document.getElementById('bc-table');\n  const tbody=document.getElementById('bc-tbody');\n\n  function resizeCanvas(){canvas.width=document.getElementById('bc-form').offsetWidth-20;drawReticle();}\n  window.addEventListener('resize',resizeCanvas);\n\n  \/\/ \ud83e\udded Draws reticle pattern\n  function drawReticle(type='grid'){\n    const cx=canvas.width\/2,cy=canvas.height\/2;\n    ctx.clearRect(0,0,canvas.width,canvas.height);\n    ctx.strokeStyle='#00b4ff';ctx.lineWidth=1.2;\n    ctx.font='10px Orbitron, monospace';ctx.fillStyle='#00b4ff';\n\n    if(type==='grid'){ \/\/ MOA grid\n      ctx.beginPath();\n      ctx.moveTo(cx,0);ctx.lineTo(cx,canvas.height);\n      ctx.moveTo(0,cy);ctx.lineTo(canvas.width,cy);\n      for(let i=1;i<=10;i++){\n        const step=i*25;\n        ctx.moveTo(cx-step,cy-5);ctx.lineTo(cx-step,cy+5);\n        ctx.moveTo(cx+step,cy-5);ctx.lineTo(cx+step,cy+5);\n        ctx.moveTo(cx-5,cy-step);ctx.lineTo(cx+5,cy-step);\n        ctx.moveTo(cx-5,cy+step);ctx.lineTo(cx+5,cy+step);\n      }\n      ctx.stroke();\n    }\n    else if(type==='dots'){ \/\/ MRAD dots\n      for(let y=-10;y<=10;y++){\n        for(let x=-10;x<=10;x++){\n          const px=cx+x*25,py=cy+y*25;\n          ctx.beginPath();\n          ctx.arc(px,py,(x===0||y===0)?2:1,0,Math.PI*2);\n          ctx.fillStyle=(x===0||y===0)?'#00ffff':'#0088ff';\n          ctx.fill();\n        }\n      }\n    }\n    else if(type==='bdc'){ \/\/ BDC tree\n      ctx.beginPath();ctx.moveTo(cx,cy);ctx.lineTo(cx,cy+200);ctx.stroke();\n      for(let i=1;i<=10;i++){\n        const y=cy+i*20,span=i*10;\n        ctx.beginPath();ctx.moveTo(cx-span,y);ctx.lineTo(cx+span,y);ctx.stroke();\n      }\n    }\n\n    ctx.beginPath();ctx.arc(cx,cy,3,0,Math.PI*2);\n    ctx.fillStyle='white';ctx.fill();\n  }\n\n  function convertUnits(v,t){const map={mps:1,fps:0.3048,m:1,yd:0.9144,mps_w:1,mph_w:0.44704,gr:0.00006479891,g:0.001,mm:0.001,in:0.0254};return v*(map[t]||1);}\n  function getEnergyColor(e){if(e<800)return'#00ffff';if(e<2000)return'#ff8800';return'#ff0000';}\n\n  function drawCompass(angle,speed){\n    const cx=60,cy=60,len=30,rad=(angle*Math.PI\/180);\n    const ex=cx+Math.sin(rad)*len,ey=cy-Math.cos(rad)*len;\n    ctx.strokeStyle='#00b4ff';ctx.lineWidth=2;\n    ctx.beginPath();ctx.moveTo(cx,cy);ctx.lineTo(ex,ey);ctx.stroke();\n    ctx.fillStyle='#00b4ff';ctx.font='10px Orbitron,monospace';\n    ctx.fillText(`${speed.toFixed(1)} m\/s`,cx-25,cy+45);\n    ctx.beginPath();ctx.arc(cx,cy,3,0,Math.PI*2);ctx.fill();\n  }\n\n  function animateTracer(x0,y0,x1,y1,h,dur,col){\n    const [r,g,b]=[parseInt(col.slice(1,3),16),parseInt(col.slice(3,5),16),parseInt(col.slice(5,7),16)];\n    const start=performance.now();\n    function step(now){\n      const t=Math.min((now-start)\/dur,1);\n      const x=x0+(x1-x0)*t, y=y0+(y1-y0)*t-h*Math.sin(Math.PI*t);\n      ctx.beginPath();ctx.arc(x,y,2,0,Math.PI*2);\n      ctx.fillStyle=`rgba(${r},${g},${b},${1-t})`;\n      ctx.shadowBlur=20*(1-t);ctx.shadowColor=col;ctx.fill();ctx.shadowBlur=0;\n      if(t<1)requestAnimationFrame(step);\n    }requestAnimationFrame(step);\n  }\n\n  function simulate(){\n    const g=id=>parseFloat(document.getElementById(id).value)||0,s=id=>document.getElementById(id).value;\n    const v=g('velocity'),vU=s('velocity_unit'),bc=g('bc'),w=g('weight'),wU=s('weight_unit'),\n          R=g('range'),RU=s('range_unit'),ZR=g('zero_range'),ZRU=s('zero_unit'),\n          SH=g('scope_height'),SHU=s('scope_unit'),WS=g('wind'),WSU=s('wind_unit'),\n          WA=g('wind_angle'),U=s('unit_type'),RET=s('reticle_type');\n    drawReticle(RET);\n\n    const v_mps=convertUnits(v,vU),r_m=convertUnits(R,RU),zr_m=convertUnits(ZR,ZRU),\n          sh_m=convertUnits(SH,SHU),wind_mps=convertUnits(WS,WSU+'_w'),m_kg=convertUnits(w,wU);\n    if(!v_mps||!r_m||!m_kg)return;\n\n    const k=0.0002;function vAt(d){return v_mps*Math.exp(-k*d\/(bc*1.2));}\n    function dropAt(d){const v=vAt(d),t=d\/((v_mps+v)\/2);return 0.5*9.81*t*t;}\n    const drop_m=dropAt(r_m),drop_z=dropAt(zr_m);\n    const corrDrop=drop_m-drop_z+sh_m;\n\n    const cross=wind_mps*Math.sin(WA*Math.PI\/180),head=wind_mps*Math.cos(WA*Math.PI\/180);\n    const eff_v=v_mps+head*0.3,t=r_m\/((eff_v+vAt(r_m))\/2);\n    const drift=cross*t*0.1*(1-bc);\n\n    const moa=1\/(r_m*0.0002909),mrad=1\/(r_m*0.001);\n    const dropA=corrDrop*(U==='moa'?moa:mrad),driftA=drift*(U==='moa'?moa:mrad);\n\n    const E=0.5*m_kg*Math.pow(vAt(r_m),2),Eft=E*0.737562,col=getEnergyColor(E);\n    const cx=canvas.width\/2,cy=canvas.height\/2,scale=10,x=cx-driftA*scale,y=cy+dropA*scale;\n\n    animateTracer(cx,cy,x,y,40,1200,col);\n\n    \/\/ Measurement lines, dot, compass\n    setTimeout(()=>{\n      ctx.beginPath();ctx.moveTo(cx,cy);ctx.lineTo(x,y);\n      ctx.strokeStyle='#00ffff';ctx.lineWidth=1;ctx.stroke();\n      ctx.beginPath();ctx.arc(x,y,5,0,Math.PI*2);\n      ctx.fillStyle=col;ctx.fill();ctx.strokeStyle='white';ctx.lineWidth=1;ctx.stroke();\n      ctx.fillStyle='#00b4ff';ctx.font='13px Orbitron,monospace';\n      ctx.fillText(`Drop ${dropA.toFixed(2)} ${U}`,x+8,y);\n      ctx.fillText(`Drift ${driftA.toFixed(2)} ${U}`,x+8,y+14);\n      drawCompass(WA,wind_mps);\n      ctx.fillText(`Energy: ${E.toFixed(0)}J \/ ${Eft.toFixed(0)}ft\u00b7lb`,10,canvas.height-20);\n    },1200);\n\n    generateCard(v_mps,bc,m_kg,wind_mps,WA,U,sh_m,zr_m,R,RU);\n  }\n\n  function generateCard(v_mps,bc,m_kg,wind_mps,WA,U,sh_m,zr_m,R,RU){\n    const step=parseFloat(document.getElementById('range_step').value)||50;\n    const stepU=document.getElementById('step_unit').value,step_m=convertUnits(step,stepU),\n          maxR=convertUnits(R,RU);\n    tbody.innerHTML='';\n    const k=0.0002;function vAt(d){return v_mps*Math.exp(-k*d\/(bc*1.2));}\n    function dropAt(d){const v=vAt(d),t=d\/((v_mps+v)\/2);return 0.5*9.81*t*t;}\n    const dropZ=dropAt(zr_m);\n    const moa=1\/(maxR*0.0002909),mrad=1\/(maxR*0.001);\n    for(let d=step_m;d<=maxR;d+=step_m){\n      const drop=dropAt(d),corr=drop-dropZ+sh_m;\n      const cross=wind_mps*Math.sin(WA*Math.PI\/180),head=wind_mps*Math.cos(WA*Math.PI\/180);\n      const eff=v_mps+head*0.3,t=d\/((eff+vAt(d))\/2);\n      const drift=cross*t*0.1*(1-bc);\n      const dropA=corr*(U==='moa'?moa:mrad),driftA=drift*(U==='moa'?moa:mrad);\n      const E=0.5*m_kg*Math.pow(vAt(d),2),Eft=E*0.737562;\n      const dist=(stepU==='yd')?(d\/0.9144).toFixed(0)+' yd':(d).toFixed(0)+' m';\n      const tr=document.createElement('tr');\n      tr.innerHTML=`<td>${dist}<\/td><td>${dropA.toFixed(2)} ${U.toUpperCase()}<\/td><td>${driftA.toFixed(2)} ${U.toUpperCase()}<\/td><td>${E.toFixed(0)} J \/ ${Eft.toFixed(0)} ft\u00b7lb<\/td>`;\n      tbody.appendChild(tr);\n    }\n  }\n\n  document.getElementById('bc-run').addEventListener('click',simulate);\n  document.getElementById('bc-toggle').addEventListener('click',()=>{\n    canvas.style.display=canvas.style.display==='none'?'block':'none';\n    table.style.display=table.style.display==='none'?'table':'none';\n  });\n\n  resizeCanvas();\n})();\n<\/script>\n\n\n\n\n    <div class=\"arfpe-calculator\">\n        <h3>Air Rifle FPE Calculator<\/h3>\n        <label for=\"arfpe_velocity\">Velocity (fps):<\/label>\n        <input type=\"number\" id=\"arfpe_velocity\" placeholder=\"Enter velocity\">\n\n        <label for=\"arfpe_weight\">Pellet Weight (grains):<\/label>\n        <input type=\"number\" id=\"arfpe_weight\" placeholder=\"Enter weight\">\n\n        <button id=\"arfpe_calculate\">Calculate<\/button>\n        <div id=\"arfpe_result\"><\/div>\n    <\/div>\n    \n\n\n    <div class=\"bscp-calculator\">\n        <h3>Ballistics Scope Calculator Plus<\/h3>\n\n        <label for=\"bscp_distance\">Distance (yards):<\/label>\n        <input type=\"number\" id=\"bscp_distance\" placeholder=\"Enter distance\">\n\n        <label for=\"bscp_velocity\">Muzzle Velocity (fps):<\/label>\n        <input type=\"number\" id=\"bscp_velocity\" placeholder=\"Enter velocity\">\n\n        <label for=\"bscp_weight\">Projectile Weight (grains):<\/label>\n        <input type=\"number\" id=\"bscp_weight\" placeholder=\"Enter weight\">\n\n        <label for=\"bscp_bc\">Ballistic Coefficient (BC):<\/label>\n        <input type=\"number\" step=\"0.001\" id=\"bscp_bc\" placeholder=\"Enter BC\">\n\n        <label for=\"bscp_unit\">Select Unit:<\/label>\n        <select id=\"bscp_unit\">\n            <option value=\"MOA\">MOA<\/option>\n            <option value=\"MRAD\">MRAD<\/option>\n        <\/select>\n\n        <button id=\"bscp_calculate\">Calculate<\/button>\n        <div id=\"bscp_result\"><\/div>\n    <\/div>\n    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