Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Stoney74 on April 30, 2007, 11:49:11 PM
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I don't want this to turn into a cannon vs. .50 cal debate, but I had a question regarding the precision of cannon rounds during WWII. I'm no ballistics expert and I couldn't find anything among Tony Williams voluminous information online...
What sort of real-life dispersions were typical for some of the more prevalent cannon? I'm assuming that the larger, lower velocity rounds, like the Mk108, would have a pretty high dispersion relative to some of the higher muzzle velocity weapons. Perhaps someone can enlighten me on what factors of a weapon create precision (and by precision, I'm talking about a situation where, all outside factors being constant, the rounds either have or do not have a tendency to hit the same spot during repeated firings).
The second part of the question is how this is modelled in AH. It seems like folks are able to "bloop" the taters (or tater-tots) at ranges in excess of 600-800 meters. Is the vertical drop the only thing that is modelled? I know you can set up the flying target and see the dispersion patterns, but they don't appear to have a relative difference other than drop, which can be countered with extreme convergence settings.
I'm just having a hard time buying that 800 meter tracking shot with the bigger cannon rounds. I accept it as a game-ism, but from a historical perspective, were these rounds capable of the kind of precision we see in AH? If so, why did most pilots only fire within 300 meters or so?
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bullets and cannons rounds go farther when fired at high altitudes. I'll try it again offline to see if this is true.
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I don't really know about the first part of your question, but as to the second... If the real life pilots from WW2 had free ammo and thousands of hours of practice (with planes to be found to shoot at), they'd hit crazy shots too.
I wouldn't be terribly suprised if the current AH subscriber base has more accumulated "hours" than the entire USAAF by now :eek:
I'd imagine guys regularly get more kills in a campaign or two than some squadrons did in the entire war, and so on and so forth.
Under those conditions, some people are going to become pretty good shots.
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I seem to recall that the Hispano had less dispersion than the M2 .50 calibre, particularly if mounted in the nose/engine as on the Whirlwind, P-38, Mosquito, Meteor and D.520.
EDIT:
Wing guns are going to be less accurate regardless of gun type simply due to the fact that wings flex and warp a bit just due to manuvering. The further out on the win the gun(s) are the worse this effect will probably be.
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I've written a lot of posts in the past concerning this topic, Stoney, and while I'm by no means a munitions expert or game engineer, my theory is that there is a lot more factors in works than just the ballistics alone. Particularly when it comes to the problem of "probability" (of long distance shots) as opposed to the "possibility" of it happening, the determining factor has actually more to do with general game environment of AH2 rather than the ballistics itself, at least according to my line of thought.
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Generally the dispersion of the gun itself is a quite minimal factor in the shooting accuracy; the other factors like aiming and gun installation issues etc. has far larger effect.
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Originally posted by Vudak
I don't really know about the first part of your question, but as to the second... If the real life pilots from WW2 had free ammo and thousands of hours of practice (with planes to be found to shoot at), they'd hit crazy shots too.
I wouldn't be terribly suprised if the current AH subscriber base has more accumulated "hours" than the entire USAAF by now :eek:
I'd imagine guys regularly get more kills in a campaign or two than some squadrons did in the entire war, and so on and so forth.
Under those conditions, some people are going to become pretty good shots.
I completely agree.
In two years I have now accumulated more than 10,000 air to air kills and get another 500-1000 per tour - that's an incredible amount of target practice a real pilot could not even dream about.
I might also point out that there are only very few guys who are really capable of hitting other fighters with the 30mm MK 108 at D600. We just notice them more than the average AH player, because they kill us, not the average guy.
If you just assume that there are about 5000 regular MA players, the average pilot seems to have a hit percentage of only 3.5 %. (3.1 % currently ranks you # 2800, 3.7% is needed for rank # 1800).
The guys with hit consitently >10% are actually quite rare, less than 2% of all AH pilots are capable of this.
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Originally posted by Lusche
I completely agree.
In two years I have now accumulated more than 10,000 air to air kills and get another 500-1000 per tour - that's an incredible amount of target practice a real pilot could not even dream about.
I might also point out that there are only very few guys who are really capable of hitting other fighters with the 30mm MK 108 at D600. We just notice them more than the average AH player, because they kill us, not the average guy.
If you just assume that there are about 5000 regular MA players, the average pilot seems to have a hit percentage of only 3.5 %. (3.1 % currently ranks you # 2800, 3.7% is needed for rank # 1800).
The guys with hit consitently >10% are actually quite rare, less than 2% of all AH pilots are capable of this.
I understand what you're saying, but...
With the Mk108, he only has to hit you with 1 round and its insta-tower, so with a 3.5% hit ratio, 30-40 rounds are all he's gonna need. I haven't been shot down by a low-scoring (or quality) 110 pilot in some time...
Regardless, I'm still having a hard time understanding the ballistic properties of these bigger but lower muzzle velocity rounds. They seem to track straight and true, just with a little more drop. Given the lower muzzle velocity, they should lose precision at a higher rate than .50 cal or 13mm right? Not to mention the shorter relative barrel length?
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Originally posted by Stoney74
I understand what you're saying, but...
With the Mk108, he only has to hit you with 1 round and its insta-tower, so with a 3.5% hit ratio, 30-40 rounds are all he's gonna need. I haven't been shot down by a low-scoring (or quality) 110 pilot in some time...
The 3.5% is overall hit percentage. Including attacks on buffs and at close range. Add to this that most of that average players don't use 108 equipped planes much (except 110G for ground atttacks), but rather hizooka or .50 cal planes. I would bet that in fighter vs fighter combat, the average players hit quote would be well under 1% when using the Mk 108.
(And like you, I haven't been shot down by a 110 for a long time. But not because of their crappy aim, but because I try very hard not to get in front of that gunship... I would think you do the same ;) )
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Well, I landed 8 kills in a K-4, but the last was 13mms only. So that comes out to 9.28 rounds per kill (65 / 7). Not bad, almost 10%.
It's possible. The gun just sucks for most situations.
As Lusche said, we all have more kills than even the top aces had. Who was the highest scoring LW pilot? Hartmann? 390-something kills? Hell I get that many in a month sometimes, he took years.
AH pilots definitely have a LOT more practice, but we also don't have air turbulence (sitting 200 yards behind an enemy plane would be hard, methinks), and a lot of other realistic concerns that would limit a pilot's ability to get kills. Fact is we can do whatever we want, and if we crash we just take off again. Real pilots couldn't do that because life was precious. In AH it's wasted nonstop with suicide porkers, dive-bombing lancasters, and suicide cv killers.
Without the worry, we're free to hone the skills well past what the "average" person in WW2 could ever be. Consider that most couldn't hit shots outside 250 yards. Most US P51 pilots went their entire career without seeing an enemy.
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Actually, it's the ammo counters and distance indicators, more than anything that attributes to the long-range shots happening in game.
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Disagree... When I'm shooting I'm not looking at range. I'm looking at sight picture.
Even if you handicapped people by removing closing/opening indicators (what the range does) folks would still learn to fire at the sight picture, because we STILL have unlimited lives in which to learn our lessons, real pilots had but 1.
Ammo counters don't matter if you are only looking for 1 fight then going RTB, as they did in real life.
In this game it matters because you can fly around in a VERY hostile VERY target rich environment for an hour and get into a dozen fights. The ammo counters reflect the environment, not the other way around.
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Originally posted by Stoney74
Regardless, I'm still having a hard time understanding the ballistic properties of these bigger but lower muzzle velocity rounds. They seem to track straight and true, just with a little more drop. Given the lower muzzle velocity, they should lose precision at a higher rate than .50 cal or 13mm right? Not to mention the shorter relative barrel length?
Why do you think precision has anything to do with muzzle velocity? The rounds take a little longer to get there (fractions of a second) and thus they drop a little more. What do you think is missing?
While the MK 108 is a so-called “low velocity” gun the muzzle velocity is still more than half a kilometer per second. It’s not a blowpipe.
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Disagree... When I'm shooting I'm not looking at range. I'm looking at sight picture.
Well, I expected as much, since you disagree with everything and everyone.
Even if you handicapped people by removing closing/opening indicators (what the range does) folks would still learn to fire at the sight picture, because we STILL have unlimited lives in which to learn our lessons, real pilots had but 1.
Amusingly, such unlimited lives don't really seem to help all that well in some of AH's contendors when a few crutches are removed. As a matter of fact, your often derogatory comments about IL2/FB/'46 damage modelling is somewhat a clear indicator in the difference of gunnery effectiveness between the two seems.
I mean really, why would you bash one game if you weren't terrible in it?
Ammo counters don't matter if you are only looking for 1 fight then going RTB, as they did in real life.
Unfortunately, the MA is a multiple engagement. Although you may be able to control your number of desired fights to some extent, in the end there's no knowing how many bad guys you would have to exchange blows with. It is quite nervous thing to be living in the Wild West, with no indication of just how many bullets you've got left in your revolver.
In this game it matters because you can fly around in a VERY hostile VERY target rich environment for an hour and get into a dozen fights. The ammo counters reflect the environment, not the other way around.
People react to what they are given with. Take away something, or put in a different thing, and they start reacting differently.
It's as simple as that.
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First of all, it's very insulting for you to say:
"I mean really, why would you bash one game if you weren't terrible in it?"
My comments about IL2's damage model have nothing to do with "being terible in it"... Matter of fact I *DO* hit in IL2 almost as well as I do in Aces High. End result is IL2 makes almost every round that isn't 30mm or greater do jack watermelon to the target.
That's neither here nor there, because I'm not talking about trouble HITTING the target. I said, if you scroll up you'll see it, folks would quite easily learn to fire based on how large the plane is in their gunsight.
Take your lame defensive attacks elsewhere.
I disagree with you because you present flawed arguments at times. THIS is one of them. You're blaming problems on icons and ammo counters. I'm not going to fault you for liking realistic flight sims. I am going to fault you for placing blame on these features where it does not exist.
Icons don't change the end result -- players in this game would still be able to know when the target is still within "sniping range."
Ammo counters do not change the way the game is played. If this game had 1-time encounters, where you had to RTB when you spotte the first enemy, regardless of the outcome, ammo counters could be removed easily. The problem is that there's always an endless stream of cons
How's that for your desire for accuracy? I see no comments that would actually change gameplay! What about the endless streams on reupping planes, the Ability to up, die, reup, die, reup, and fight the same person 5 times in a row until they run out of ammo and fuel and die near your start field?
In the environment that AH has, you need to know how much fuel you have, how much ammo you have, and judge when its time to get the hell out of Dodge. In real life this was EASY. In this game it is the opposite. You can't compare this game to real life in any way other than the performance specifications of the aircraft.
So take the defensive attacks and consider that you might be wrong. I wasn't rude I didn't warrant that type of reply.
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Originally posted by Krusty
In the environment that AH has, you need to know how much fuel you have, how much ammo you have, and judge when its time to get the hell out of Dodge. In real life this was EASY.
That is a very arrogant and incorrect statement that I think many real life pilots would disagree with at great length.
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I do some pretty extensive shooting with muzzleloading firearms, and have been doing so for a good 20 years. I'm very picky about the guns I shoot, how they're loaded, and the factors that influence my accuracy. My sighting in and tweaking are done on a bench, my target shooting and competitions are done off-hand (standing, with no rest). I shoot only flintlock muzzleloaders, which are also "traditionally" styled. I easily fire 300-400 well aimed shots per year with these weapons. I also shoot 22-250's, .270's, .22's (LR, Shorts, CB's, and Magnums), 38's, and a 12 gauge using both shot and slugs.
I can throw some information in to answer or at least give light to the slower heavier projectile question which originally opened this thread.
Regardless of propellent type used, the larger sized projectiles do not lose much, if anything, due to their size- at least as far as accuracy potential is concerned. The size really isn't the issue. Barrel quailty/straightness, sights, aiming ability, weapon soundness, and consistancy of loading affect accuracy much more.
The big projectiles slow down faster, and as a result follow a more "arched" trajectory. They are more prone to wind-drift, a factor not in play in AH. When a bullet is stabilized by the rifling, it is spinning along the longitudinal axis. It slows down in forward flight, but this spinning does not slow down nearly as fast. As long as it spins enough, it is stabilized. Its RPM will slow down enough to lose stability well past the point where the projectile has lost enough forward speed to be effective. So it will lose power well before it loses its potential to fly straight.
Of course, as it slows in forward movement it also becomes more succeptable to wind-drift, etc. And a spinning projectile will "walk" to the side a bit, which seems more pronounced as it slows.
It's interesting to note that a larger diameter projectile needs less spin to stabilize than a smaller diameter projectile. The ratio of length to diameter matters tons, too. My .54 caliber roundball needs only a 1 in 70 inch twist to stabilize, where my .50 caliber roundball needs about 1 in 56. Conical projectiles need more rapid twist to be stabilized. I'm not actually going to get up to check, but I believe my .270 needs about 1 in 17 inches, and my 22-250 needs 1 in 10 or so. The greater the ratio of length/diameter, the faster the twist. Also realize that the amount of inches traveled during one full rotation isn't the real important thing, the RPM is. Firing a projectile at a faster speed also increases the RPM. A bullet traveling a given distance spins the same number of revolutions regardless of its speed. You can make it spin faster/slower though by increasing or decreasing its forward speed (how much powder, more or less).
Sights and shooting/aiming ability are more important, given an adequate firearm. My .54 flintlock with its 1 in 70 twist will fire shots into a 3 inch group at 100 yards all day, even with open sights. I know lots of folks that can't do that with a scoped 30-06 or .270. My scoped .270 will shoot 2 inch groups at 200 yards. So would my .54 if there was no wind and I attached a scope. My 22-250 shoots accurately enough to shoot dimes at 200 yds. Why? Because it has less recoil to throw off my aim, the bullets are cheaper, so I shoot more (practice), and it is more enjoyable to shoot with the lower recoil.
Larger projectiles are accurate. They need even less spin to be stabilized, because they are generally shorter. They don't usually need the extra length because at the higher diameter they are already heavy enough. Heck, my .75 Brown Bess will shoot 4 inch groups at 75 yards, and has no rifling, a horribly slow lock-time (try aiming with a fireball a few inches from your eye), and a very primitive stock configuration. It's muzzle velocity is only about 800 FPS, compared to my .54 rifle at 1800 FPS, my .270 at 3000 FPS, and my 22-250 at about 4000 FPS.
With the slower velocity, a stationary target is easiest to hit. So flying straight away from one is bad.
Obviously more factors play in here, but it would be best to read a book on ballistics that to explain them all here...
MtnMan
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Originally posted by mtnman
Obviously more factors play in here, but it would be best to read a book on ballistics that to explain them all here...
MtnMan
Thanks for the reply. I follow all of that, and didn't realize the lower rifling to stabilization factor for larger rounds, although I did note that the patterns got tighter for the smaller rounds.
And, Viking, to answer your question, I don't know--perhaps you can enlighten me?
What I do know is that with a muzzle velocity of 540 meter/sec, it would take a round almost 1.5 seconds just to make the 800 meter trip, and that's not even factoring for the additional 200 meters I would have travelled over the course of that time doing approximately 300 mph indicated. If you factor that in, it would be almost be a 2 second flight time for that round to cover that distance, not compensating for deceleration.
And comparing it to the Ma Deuce and Hispano (with 930m/s and 880 m/s respectively), I think its safe to say comparitively that it was a "low muzzle velocity weapon". In the WWII aviation ordnance world, much lower than its peers.
I could be completely off-base here, that's why I asked the question.
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Hi,
in aircombat the dispersion factor on common shooting distances(30-400m) is more related to the mount of the weapon than the weapon itself.
Fuselage mounted weapons tend to have a smaler dispersion than wing mounted weapons, cause wings tend to twist.
Kweassa,
i absolut disagree to your "distance info / amo counter" assumption.
I often play AH without icons and to the ammo counter i rarely look if iam in a fight anyway, but i still make long distance shots and i hit, specialy with Hispanos and .50cal´s.
In EAW we only have ammo counter for the german planes and we play often absolutly without icons, but long distance shots are common.
In IL-2, flying a plane with .50cal´s or russian guns, long distance shots are also nothing special, although many play it absolut without icons. Although in that game strait 6oc hits dont happen that easy at all, but if a plane turn in maybe 800m distance its good possible to hit it, strangewise despite the need of a lead, while shooting.
The hability to make long distance kills imho depends to the ammo load, gun and pilot skill(experience), not to the ammo counter or distance information.
A experienced pilot have a good feeling about the number of rounds he shot and how many are left, and for a experienced "no icon gamer" its no problem to estimate the distances.
Greetings,
Knegel
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Originally posted by Lusche
The guys with hit consitently >10% are actually quite rare, less than 2% of all AH pilots are capable of this.
So, I have to assume that, despite my continous whining, I'm a good shot? :D
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Originally posted by Gianlupo
So, I have to assume that, despite my continous whining, I'm a good shot? :D
In long range, yes. :(
:D :aok
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:lol That was a lucky shot on your turret! ;) :cool:
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Stoney, I suggest you get up in the air and try shooting someone down at 800 yards with a 30mm as you obviously wonder how anyone can make such a shot. ;) I'd say it needs a briefly unmaneuvering target and some luck.
Your question is good and in the past I have provided a chart about dispersion comparison I found from another site.
The shortness or length of barrel is not generally the deciding factor in accuracy but the longer barrel gives more muzzle velocity and thus flatter projectile arch.
Also the ROF affects this and the wing warpage is is propably only one thing affecting the accuracy. Other factors are ROF, and rigidness of gun mounting and homogenity of the ammo used.
That last factor would probably increase the accuracy of mtnman's older guns, too. If he could somehow assure that the powder load, bullet weight (and weight distribution), shape and tightness in the barrel (paper or cloth gasket) are always in very tight limits there are hardly limits for accuracy of those old guns. In practice the loading process cannot be as accurate so certain amount of dispersion is bound to happen.
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Found it:
Here are the results of a lenghty research into dispersion data, which is quite hard to come by...
The data is based on 100% diameter dispersion with 1 mil = 1/1000th of rad, the kind of mount is precised next to the weapon. 75% dispersion diameter is supposed to be half the 100% diameter which seems quite true for most weapons, this value is provided when quoted in the source (M2 data for instance).
We can clearly see the impact of the wing mounting compared to engine mounting, the later seems to have absorbed recoil and vibration much better... indeed dispersion is at least 2 times greater with wing mounted weapons.
Engine mount are the most efficient but nose mounting or cowling mounting does not provide the same amount of precision the mount being much more prone to vibration it seems.
Note that US data on the M2 is confusing since the reference data comes from a P-38 nose mounted M2, but the US manuals use the same dispersion data for wing mounted weapons. Either the P-38 mounts are really up to no good or the manuals make a wrong assumption when it comes to wing dispersion. I tend to believe the later, i think the wing mounted M2 would have had a dispersion of at least 12mils and probably more.
If you quote this data on other sites/bbs please precise the source being AAW. TIA
H means Height (or max dispersion diameter) as i previously used vertical and lateral dispersion values.
D means distance.
Units are metric.
German Weapons
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MG-17 Cowling mounted (Bf 109F-2 / Bf 109F-1 actual tests)
H = 0.60 / 0.8 m
D = 100 m
R/D = 60/10000 80/10000
= 6 mils / 8 mils
MG-131 Cowling mounted (Fw 190A - theorical max)
H = 1m
D = 100m
H/D = 100/10000
= 10 mils
MG-151/15 Engine mounted (Bf 109F-2 actual test)
H = 0,35 m
D = 100 m
H/D = 35/10000
= 3.5 mils
MG-FF Engine mounted (Bf 109F-1 actual test)
H = 0,2 m
D = 100m
H/D = 20/10000
= 2 mils (very tight patern)
MG-FF Wing mounted (Bf 109E-3 actual test)
H = 0,35 m
D = 100m
H/D = 35/10000
= 3.5 mils
MG 151/20 Engine mounted (Bf 109G-6 - theorical max)
H = 0.3m
D = 100m
H/D = 30/10000
= 3 mils
MG 151/20 Wing mounted - inner (Fw 190A - theorical max)
H = 0.7m
D = 100m
H/D = 70/10000
= 7 mils
MG 151/20 Wing mounted - outer (Fw 190A - theorical max)
H = 0.8m
D = 100m
H/D = 80/10000
= 8 mils
MK 108 Engine mounted (Ta 152 - therorical max)
H = 0.35
D = 100m
H/D = 35/10000
= 3.5 mils
Allied Weapons
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M2 Nose mounted P-38 (USAAF 1944 Gunnery manual)
H = 1.88 m
D = 229 m
H/D = 188/22900
= 8.2 mils (75% = 4.1 mils)
Hispano 20mm Nose mounted P-38 (USAAF 1944 Gunnery manual)
3 mils 75%
6 mils 100% assumed
From "Calculated "base" dispersion of guns based on energy delivered" thread in A&V forum.
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An actually discussion.
Thought I was being beckoned.
as you were.
*Quickly closes door *
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Originally posted by Stoney74
I understand what you're saying, but...
With the Mk108, he only has to hit you with 1 round and its insta-tower, so with a 3.5% hit ratio, 30-40 rounds are all he's gonna need. I haven't been shot down by a low-scoring (or quality) 110 pilot in some time...
Regardless, I'm still having a hard time understanding the ballistic properties of these bigger but lower muzzle velocity rounds. They seem to track straight and true, just with a little more drop. Given the lower muzzle velocity, they should lose precision at a higher rate than .50 cal or 13mm right? Not to mention the shorter relative barrel length?
Hmmm.......
They don't go straight when I shoot em!
I've watched em go to the right, the left high low or a combination.
Missed allot of badguys with it!
When I use the .target command I've watched the rounds go all over the target!
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Originally posted by Charge
From "Calculated "base" dispersion of guns based on energy delivered" thread in A&V forum.
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If I remember correctly, 1 mil dispersion is equal to 1 meter left/right at 1000 meters range, yeah?
Anyone know what the mil values are for the .target function? I did some test firings this morning to include screen shots for analysis and noticed some interesting trends. Also, noticed almost every cannon in the game on that list, except the Mk108.
I'll post the screen shots later...
Thanks Charge.
EDIT: Just saw the Mk108 data at the end--sorry...
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The Horizontal lines in the tank sight are 5 mils wide.
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HT, you mean the .target sight?
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Originally posted by Gianlupo
So, I have to assume that, despite my continous whining, I'm a good shot? :D
Gianlupo Tour 87
Kills Hit Percentage 14.30
:O :O :O
Fortunately you flow the ki 84 so low yesterday :rolleyes: :rolleyes:
:aok
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Lol, that was my best result, IIRC. :)
And attacking big targets like bombers helps in getting a better hit percentage. ;) I think my average hit percentage in the last 12 tours is about 10/11%.
I like to fly my Ki low in the dirt, I give the best in the worst situations! :D
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Originally posted by Vudak
I don't really know about the first part of your question, but as to the second... If the real life pilots from WW2 had free ammo and thousands of hours of practice (with planes to be found to shoot at), they'd hit crazy shots too.
I wouldn't be terribly suprised if the current AH subscriber base has more accumulated "hours" than the entire USAAF by now :eek:
I'd imagine guys regularly get more kills in a campaign or two than some squadrons did in the entire war, and so on and so forth.
Under those conditions, some people are going to become pretty good shots.
if they took all noobs out then they would not land as many.