JayPee Posted August 17, 2014 Share Posted August 17, 2014 Just wondering.. The GAU-8/A's AP round clearly suffers less from ballistic drop than the HEI round. Why don't designers tune-down the AP's ballistic profile so it matches the HEI round? Would that perhaps reduce the kinetic punch of the AP round? i7 4790K: 4.8GHz, 1.328V (manual) MSI GTX 970: 1,504MHz core, 1.250V, 8GHz memory Link to comment Share on other sites More sharing options...
OutOnTheOP Posted August 17, 2014 Share Posted August 17, 2014 Just wondering.. The GAU-8/A's AP round clearly suffers less from ballistic drop than the HEI round. Why don't designers tune-down the AP's ballistic profile so it matches the HEI round? Would that perhaps reduce the kinetic punch of the AP round? Exactly. Big, dense DU bullet will lose speed slower than low-density HE ones. You would have to INTENTIONALLY make the AP rounds slower and draggier to match the ballistic profile of the HE round. Why would you go out of your way to make the gun weaker, just to make them have precisely the same ballistics? The only time the impact points significantly diverge is at very long range (mile plus), low-angle shots anyway. Link to comment Share on other sites More sharing options...
JayPee Posted August 17, 2014 Author Share Posted August 17, 2014 If it wouldn't make the round less effective I'd seriously consider letting both types of ammo match in terms of ballistics.. i7 4790K: 4.8GHz, 1.328V (manual) MSI GTX 970: 1,504MHz core, 1.250V, 8GHz memory Link to comment Share on other sites More sharing options...
OutOnTheOP Posted August 17, 2014 Share Posted August 17, 2014 If it wouldn't make the round less effective I'd seriously consider letting both types of ammo match in terms of ballistics.. Right, but to do that, you would have to intentionally make the AP round slower (technically, draggier- they'd come out the muzzle at the same speed, but would lose speed more rapidly). As you yourself identified, the AP round relies on kinetic energy for penetration. Kinetic energy is E=MC^2. Energy squares with velocity. Faster is mo' bettah. Link to comment Share on other sites More sharing options...
Flagrum Posted August 17, 2014 Share Posted August 17, 2014 Just wondering.. The GAU-8/A's AP round clearly suffers less from ballistic drop than the HEI round. Why don't designers tune-down the AP's ballistic profile so it matches the HEI round? Would that perhaps reduce the kinetic punch of the AP round? Yes, the AP rounds are the reason why the GAU-8 is there in the first place. Tuning those down would be somewhat contradictionary. On the other hand, the difference in the ballistics of the two types is negligible. You are supposed to shoot the GAU-8 at ranges where it doesn't really matter anymore. Link to comment Share on other sites More sharing options...
Emu Posted August 17, 2014 Share Posted August 17, 2014 The API rounds already are slower than the HEI rounds but they have more KE due to weight, so they don't slow as fast. Against MBTs the two dots should coincide when you fire. Very good way of gauging distance on the fly. Link to comment Share on other sites More sharing options...
cichlidfan Posted August 17, 2014 Share Posted August 17, 2014 You are supposed to shoot the GAU-8 at ranges where it doesn't really matter anymore. I think that if you are close enough for the two dots to be on significantly different targets, then you have other things to worry about. ;) ASUS ROG Maximus VIII Hero, i7-6700K, Noctua NH-D14 Cooler, Crucial 32GB DDR4 2133, Samsung 950 Pro NVMe 256GB, Samsung EVO 250GB & 500GB SSD, 2TB Caviar Black, Zotac GTX 1080 AMP! Extreme 8GB, Corsair HX1000i, Phillips BDM4065UC 40" 4k monitor, VX2258 TouchScreen, TIR 5 w/ProClip, TM Warthog, VKB Gladiator Pro, Saitek X56, et. al., MFG Crosswind Pedals #1199, VolairSim Pit, Rift CV1 :thumbup: Link to comment Share on other sites More sharing options...
Flagrum Posted August 17, 2014 Share Posted August 17, 2014 I think that if you are close enough for the two dots to be on significantly different targets, then you have other things to worry about. ;) Hrm? Link to comment Share on other sites More sharing options...
cichlidfan Posted August 17, 2014 Share Posted August 17, 2014 Hrm? Looks like an Apache pilot. :D ASUS ROG Maximus VIII Hero, i7-6700K, Noctua NH-D14 Cooler, Crucial 32GB DDR4 2133, Samsung 950 Pro NVMe 256GB, Samsung EVO 250GB & 500GB SSD, 2TB Caviar Black, Zotac GTX 1080 AMP! Extreme 8GB, Corsair HX1000i, Phillips BDM4065UC 40" 4k monitor, VX2258 TouchScreen, TIR 5 w/ProClip, TM Warthog, VKB Gladiator Pro, Saitek X56, et. al., MFG Crosswind Pedals #1199, VolairSim Pit, Rift CV1 :thumbup: Link to comment Share on other sites More sharing options...
Emu Posted August 17, 2014 Share Posted August 17, 2014 Even if you slowed the API round down, you'd still end up with two dots except they'd swap places at some point depending on range, which would be confusing. Whereas as things stand, the two dots just get closer together the closer you get. Link to comment Share on other sites More sharing options...
JayPee Posted August 17, 2014 Author Share Posted August 17, 2014 How would the relation between the two dots flip IF they hass the same ballistic profile? Anyway, on topic, I now understand why you don't want to tune down the AP's ballistic profile as it decreases the kinetic punch/effectiveness of the round. i7 4790K: 4.8GHz, 1.328V (manual) MSI GTX 970: 1,504MHz core, 1.250V, 8GHz memory Link to comment Share on other sites More sharing options...
NeilWillis Posted August 18, 2014 Share Posted August 18, 2014 The whole point is that they could never have the same ballistic profile unless they were identical weights and identical shapes. All you could do would be to have them match at some arbitrary point in space - which is the exact situation now. The only change you could achieve would be to have them match at a different arbitrary point in space. As it stands, they match just where you need them to match. So where is the issue exactly? 1 Link to comment Share on other sites More sharing options...
dumgrunt Posted August 18, 2014 Share Posted August 18, 2014 (edited) thats the whole point, unless the BC, mass and the velocity of the projectiles were identical you would never get an identical MPI throughout the range on the weapon. What Emu is saying is that if you slowed down the API round, so they that both would have an identical MPI at say 1800m (1nm), then the HEI MPI would be above at range shorter, and the API would have an MPI above at ranges longer. this is the mechanics of ballistics and trajectories. i havent tried it, but certainly you might find the MPI reverse at ranges around the 300m mark on the reticle. the muzzel velocity of the API round is actually a good few hundred FPS slower than the HEI round. but like anywhere else, it is BC and momentum that dictate terminal performance and how "flat" a projectiles path is at longer ranges. a good example would be to compare bullet drop at ranges past 500m for the 5.56 and the 7.62 NATO ball ammunition. *BC ballistic co efficient *MPI mean point of impact edit: oops sniped ^ Edited August 18, 2014 by dumgrunt [sIGPIC][/sIGPIC] Link to comment Share on other sites More sharing options...
EtherealN Posted August 18, 2014 Share Posted August 18, 2014 Kinetic energy is E=MC^2. Careful there Einstein. ;) Ek = ½mv² You don't use c, being the speed of light, for Kinetic energy calculation, that's for calculating the total rest energy of an object with mass. :) [sIGPIC][/sIGPIC] Daniel "EtherealN" Agorander | Даниэль "эфирныйн" Агорандер Intel i7 2600K @ 4.4GHz, ASUS Sabertooth P67, 8GB Corsair Vengeance @ 1600MHz, ASUS GTX 560Ti DirectCU II 1GB, Samsung 830series 512GB SSD, Corsair AX850w, two BENQ screens and TM HOTAS Warthog DCS: A-10C Warthog FAQ | DCS: P-51D FAQ | Remember to read the Forum Rules | | | Life of a Game Tester Link to comment Share on other sites More sharing options...
OutOnTheOP Posted August 19, 2014 Share Posted August 19, 2014 Careful there Einstein. ;) Ek = ½mv² You don't use c, being the speed of light, for Kinetic energy calculation, that's for calculating the total rest energy of an object with mass. :) Yes, V as a variable, rather than constant C (which is a value FOR V, still). The 1/2 is arbitrary, and scales linearly- it's not necessary in the equation. The point still remains that energy scales linearly with mass and squares with velocity. Link to comment Share on other sites More sharing options...
Supersheep Posted August 19, 2014 Share Posted August 19, 2014 The 1/2 is arbitrary Isn't that from the integration of the force over distance? Mathemagical, but not arbitrary IMHO. Now my High School AP course ends there, so I don't know how I'd be able to scale out a constant (it's there for a reason). The PVC Pipe Joystick Stand How to thread Link to comment Share on other sites More sharing options...
Emu Posted August 19, 2014 Share Posted August 19, 2014 How would the relation between the two dots flip IF they hass the same ballistic profile? Anyway, on topic, I now understand why you don't want to tune down the AP's ballistic profile as it decreases the kinetic punch/effectiveness of the round. They can't have the same ballistic profile because one is heavier. Link to comment Share on other sites More sharing options...
pitdesigner Posted August 19, 2014 Share Posted August 19, 2014 30mm party mix: why allow two ballistic profiles? The reason its that way is because thats the way it is in real life, it really is a very small difference Link to comment Share on other sites More sharing options...
EtherealN Posted August 19, 2014 Share Posted August 19, 2014 The reason its that way is because thats the way it is in real life, it really is a very small difference He was asking about real life. That's why this was posted in the Reality subsection Military and Aviation. ;) [sIGPIC][/sIGPIC] Daniel "EtherealN" Agorander | Даниэль "эфирныйн" Агорандер Intel i7 2600K @ 4.4GHz, ASUS Sabertooth P67, 8GB Corsair Vengeance @ 1600MHz, ASUS GTX 560Ti DirectCU II 1GB, Samsung 830series 512GB SSD, Corsair AX850w, two BENQ screens and TM HOTAS Warthog DCS: A-10C Warthog FAQ | DCS: P-51D FAQ | Remember to read the Forum Rules | | | Life of a Game Tester Link to comment Share on other sites More sharing options...
pitdesigner Posted August 19, 2014 Share Posted August 19, 2014 Haha my bad! Well as I were Link to comment Share on other sites More sharing options...
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