Ballistics - Improve B_127x54_Ball values

addons/atragmx/functions/fnc_initGunList.sqf

@@ -38,7 +38,7 @@ if (_resetGunList) then {
                       ["12.7x99mm AMAX"    ,  852, 100, 0.0907214, -0.00037397, 8.89, 0, 2, 10, 120, 0, 0, 48.60, 12.7, 38.10, 1.050, 1, "ASM" , [[-15,833],[0,840],[10,847],[15,852],[25,866],[30,875],[35,886]]       , [[0,0],[0,0],[0,0],[0,0],[0,0],[0,0],[0,0]], true],
                       ["12.7x99mm"         ,  892, 100, 0.0879633, -0.00058679, 8.89, 0, 2, 10, 120, 0, 0, 41.92, 12.7, 38.10, 0.670, 1, "ASM" , [[-15,873],[0,880],[10,887],[15,892],[25,906],[30,915],[35,926]]       , [[0,0],[0,0],[0,0],[0,0],[0,0],[0,0],[0,0]], true],
 
-                      ["12.7x54mm"         ,  299, 100, 0.3567550, -0.00019568, 6.60, 0, 2, 10, 120, 0, 0, 48.60, 12.7, 24.13, 1.050, 1, "ASM" , [[-15,297],[0,298],[10,299],[15,299],[25,301],[30,302],[35,303]]       , [[0,0],[0,0],[0,0],[0,0],[0,0],[0,0],[0,0]], true],
+                      ["12.7x54mm"         ,  295, 100, 0.3681230, -0.00037716, 6.35, 0, 2, 10, 120, 0, 0, 48.20, 13.0, 25.00, 0.519, 1, "ICAO" , [[-15,293],[0,294],[10,295],[15,295],[25,297],[30,298],[35,299]]       , [[0,0],[0,0],[0,0],[0,0],[0,0],[0,0],[0,0]], true],
 
                       [".50 Beowulf"       ,  549, 100, 0.1468500, -0.00209809, 6.60, 0, 2, 10, 120, 0, 0, 21.64, 12.7, 50.80, 0.210, 1, "ASM" , [[-15,547],[0,548],[10,549],[15,549],[25,551],[30,552],[35,553]]       , [[0,0],[0,0],[0,0],[0,0],[0,0],[0,0],[0,0]], true],
 

addons/ballistics/CfgAmmo.hpp

@@ -629,19 +629,19 @@ class CfgAmmo {
     class B_127x33_Ball: BulletBase {
         tracerScale = 1.3; //1.2;
     };
-    class B_127x54_Ball: BulletBase {
-        airFriction=-0.00019568;
-        tracerScale = 1.3;//
-        ACE_caliber=12.954;
-        ACE_bulletLength=64.516;
-        ACE_bulletMass=48.6;
-        ACE_ammoTempMuzzleVelocityShifts[]={-2.655, -2.547, -2.285, -2.012, -1.698, -1.280, -0.764, -0.153, 0.596, 1.517, 2.619};
-        ACE_ballisticCoefficients[]={1.050};
-        ACE_velocityBoundaries[]={};
-        ACE_standardAtmosphere="ASM";
-        ACE_dragModel=1;
-        ACE_muzzleVelocities[]={300};
-        ACE_barrelLengths[]={436.88};
+    class B_127x54_Ball: BulletBase { // Russian 12.7x55mm subsonic Патрон СЦ-130 ПТ2 (STs130PT2) https://memo-randum.net/katalog/boepripasy/patrony/patron-sts-130-pt2/
+        airFriction = -0.00037716; // based on MV 295m/s and G1 BC 0.519
+        tracerScale = 1.3; // B_127x54_Ball 1.5
+        ACE_caliber = 13.01; // https://en.wikipedia.org/wiki/12.7%C3%9755mm_STs-130
+        ACE_bulletLength = 63.75; // average length 63.5, 64mm
+        ACE_bulletMass = 48.2;
+        ACE_ammoTempMuzzleVelocityShifts[] = {-2.655, -2.547, -2.285, -2.012, -1.698, -1.280, -0.764, -0.153, 0.596, 1.517, 2.619}; // default ACE_ammoTempMuzzleVelocityShifts values /10. Muzzle velocity shift 0 at 70°F (21°C), -1m/s at 15°C
+        ACE_ballisticCoefficients[] = {0.519}; // based on time of flight 1.0798s at 300m: G1 ICAO 0.519 (Strelok Pro and EBC V2), unknown measurement conditions https://memo-randum.net/katalog/boepripasy/patrony/patron-sts-130-pt2/
+        ACE_velocityBoundaries[] = {};
+        ACE_standardAtmosphere = "ICAO";
+        ACE_dragModel = 1;
+        ACE_muzzleVelocities[] = {296}; // Muzzle Velocity shift +1m/s at 70°F (21°C) (70°F: Temp vs MV chart zero), 295m/s at 15°C (ICAO: 15°C, 1013.25 hPa, 0%) according to 10Rnd_127x54_Mag initSpeed
+        ACE_barrelLengths[] = {450}; // according to ASP-1 Kir barrel length, VKS: https://en.wikipedia.org/wiki/VKS_sniper_rifle
     };
     class B_127x99_Ball: BulletBase {
         timeToLive=10;

addons/ballistics/CfgMagazines.hpp

@@ -719,7 +719,7 @@ class CfgMagazines {
     };
 
     class 10Rnd_127x54_Mag: CA_Magazine {
-        initSpeed = 300;
+        initSpeed = 295; // according to ACE_muzzleVelocities ICAO conditions (15°C, 1013.25hPa, 0%)
     };
 
     class 150Rnd_556x45_Drum_Mag_F: CA_Magazine {

addons/ballistics/CfgWeapons.hpp

@@ -66,8 +66,8 @@ class CfgWeapons {
     // ASP-1 Kir
     class DMR_04_base_F: Rifle_Long_Base_F {};
     class srifle_DMR_04_F: DMR_04_base_F {
-        ACE_barrelLength = 450.088;
-        ACE_barrelTwist = 203.2;
+        ACE_barrelLength = 450;
+        ACE_barrelTwist = 250; // 10" (254mm), without datas and from a gyroscopic stability analyse tool (EBC V2), 10" seems the best gyroscopic stability compromise
         initSpeed = -1.0;
     };