"Discuss some tank-tank gunfire routines?" Topic

Like most of you on this site, I too am always tweaking published rules with house rules and trying to put in new information that becomes available for WWII tank-tank games. As a long distance shooter and competitor and having been around armored vehicles in the military I've always "fanaticized" about a tank game where I could lay my cross hair sights on the target and fire away and see the results, exact hit location, etc. (my wife knows about my fantasy but is not jealous anymore, she knows she can't compete). The closest we ever came was building 1/35 scale Tamiya tanks and taking them out to an open field and each team shooting at the opposing teams tanks with a cheap scope mounted on a BB gun. I can still picture the indentation marks a BB would leave on that beautifully sloped T-55 plastic turret as it would ricochet off. Cool!

In the last few years there has been a wealth of technical information available over web along with many talented and knowledgeable people. Things like trajectory tables and formulas, test firings, personal histories, AAR's, etc. Unfortunately other than a computer game, game aided program or spreadsheet it's been hard to duplicate these results or integrate them into a miniature or board game using traditional CRT's, charts and DRM's. There are quite a few that are playable and give a good feel to armored warfare. However, I don't want to know that I "missed" my target because I rolled a 9 rather than a 10+. I'd like to know by how much, why and make the adjustment for the follow-up shot using my skill, not a DRM.

My son and I shoot the M1 Garand at 600 yards with iron sights. When I spot for him I can pick up the heat/vapor trail of that venerable 107 year old 30-06 round at about 400 yards with my spotting scope and watch as it makes that beautiful and poetic arc through the air and then make its descent to its final destination and target while drifting ever so gracefully to the left from the spin (I get chills just describing it). I can see the impact of the bullet and tell him what sight adjustments to make and walk him into the center of the bulls eye. It's moments like that when I envision myself as an experienced tank commander on the Eastern Front commanding an 88mm anti-tank gun and picking off unsuspecting T-34's at 3,500 yards.

Malen Sie einen Ring auf dem Lauf, Otto
(Paint another ring on the barrell, Otto)

Over the years I've been tinkering on and off developing a tank gun fire simulation (not really a game)that uses a true trajectory table and round dispersions, range estimation and aiming errors (no digital aids, spreadsheets or GAPs). It replaces almost all die rolls with column shifts on a chart with milliradian values at different ranges. No math other than adding a few numbers. Each gun type has values at 100 yard increments out to 3,000 yards for penetration at 0 degrees, trajectory (for range estimation error), accuracy (round dispersion) and time of flight (for firing at moving targets) and fits on one side of a 3x5 index card. The milliradian and range estimation charts are printed on the sides of an 8.5 x 11 inch sheet. There are 5-8 steps to go through that adjust your aim point on the target (yes, I got the cross hairs back) based on range estimation error, aim point error, moving target lateral movement and round dispersion that move your desired aim point (which is anywhere on the tank silhouette you want). You can see if you missed by six inches or six feet and adjust your range estimation for follow-up shots. There is no "To Hit Die Roll" as the round hits (or misses) where the aim point ends up. That means no die rolls for hit location, critical hit, target size DRM, aspect/angle, etc. I doubt if this could be a commercial venture but I would be interested in discussing some of the finer points of tank gunfire with some of the people on TMP.

Thanks,
Wolfhag

Wehrmacht fanboy alert!
Wehrmacht fanboy alert!

Hoser

Hoser,
Thanks for the Wehrmacht fanboy alert!

I'm half German with a Grandfather named Otto and son named wolfgang. I like long distance shooting but could not think of an Allied unit or vehicle that exemplifies that so I went with a German one. I've voted for the Sherman as the WWII tank that was most effective in accomplishing it's mission in the war, including the Pacific theater. That's another topic. Also, I shoot an M1, not a Mauser.

Wolfhag

Ditto,
Thanks for the response.

I'm only working on pre-1946 stuff. That's difficult enough.

I've covered Bore Sighting and "balancing the bubbles" for gun and trunnion tilt and angle sitting on the ground with an aiming error adjustment (does that handle it?). I would expect the gunner could spend the extra time setting that up after stopping or use his best judgement for an aiming offset.

Follow up shots – Correct me if I'm wrong here. Example: The range estimation for the initial shot is 1,000 yards. The tracer is observed passing over the target. I've seen how the Sherman gun sight was used in moving the sight to "move" the next round on to the target. Sometimes the gunner could not spot and the TC needed to give mil or MOA corrections to the gunner. I've read that there were standard corrections depending on range but normally adjustment was about 20% of the initial estimated range moving to 10% in effect bracketing.

Shot Observation – Yes. Where the tracer is observed, not lands.

Penetration – That's problematic from the viewpoint of what sources you use, time frame and even production runs and ammo lot numbers. I'm saving that for later. I'm going to try and use penetration values at 0 slope to be able to use charts that show slope and vertical angle armor values.

Other errors: I do have a "mil aiming error" (gunner not sighting or laying gun correctly) that should account the most misses after the range estimation error. It helps cover a lot of variables like hurrying or taking your time aiming, poor lighting conditions, firing through smoke/haze, mirage, target hull down/camo, firing at muzzle flash only, firer moving. The aiming error can offset the aim point from .5 to 2.5 mil depending on crew training and a bell curve and other variables.

Round dispersion: Based on test firing data I've found. It seems most good high velocity guns will have a base mil error of .5 to 1 mil. A bell curve could increase that 2-3 times. A good AT gun should put 60% of it's rounds within 2-5 feet of the adjusted aim point (adjusted for range and aim error) at 2,000 yards based on test firings. Could be more or could be less. I've based the mil ratings at range from test firing results that gave a % chance for hitting a 2x2.5 meter target at known range and under ideal and combat conditions. Different rounds have slight variations, like HE, APCR and sabots. I haven't taken into account ammo lots, powder temp as that's a little hard to define and not taken into account in WWII that I'm aware of. I would expect it would effect the round dispersion.

Hitting a moving target: Have ideas but nothing firm. Will most likely be an aiming error based on amount of lateral of movement and TOF.

One thing I've learned from this project is it's easy to figure out how a round can hit but harder to figure out how it misses. That's the unknown, stupid mistakes, fortunes of war, etc that are hard to define. Knowing exact range, having a finely maintained and tuned weapon, ideal weather conditions, good gunner, optics and ammo can hit a 2x2 meter target almost 50% of the time out to 2,000 yards.

My goal is to figure a system using mil ratings and column adjustments rather than DRM's and duplicate the reasons rounds missed. If that's achievable then making a game of it would entail the normal deletions and abstractions of the "less" important factors. I doubt if it would have broad appeal. I could end up putting it into a program or spreadsheet as I've done with other games.

You crewed a Leopard – I'm impressed! If you could relate how most of the gunnery misses occurred that would be great info. Much of my info is from a Marine buddy that crewed a 90mm M-48A2 in the early 1970's. He said if you didn't hit them on your second shot you should not expect to get a third one off.

Wolfhag

Was observing a U.S. Army 37mm ATG at the 1ID museum last year. The docent pulled a twelve inch tube out of a box and snapped it onto a mount on the gun. That was the sight. Talk about analog solutions!

We do this now, but it is a computer game call Panzer Command: Ostfront.

Note there is no need for 100 m increments on an accuracy table. Our table changes at the distance where the chance to hit reduces by 10%. There is no way to do this without die rolls. It is a matter of probability. All actual data from laboratory tests result in numbers compiled that are based on probability.

Mobius,
Thanks for the response. In gathering information on the internet I've run across your stuff on other sites. Amazing work on the Ostfront game. I watched a few of your Youtube videos too but I don't have the game.

I may have given the wrong impression about "randomizing" the effects of the dynamics of tank gunnery. I'm trying to get away from traditional wargame techniques of a base to hit number modified by DRM's. There is nothing out there I could improve on. The randomizing I'm doing is to generate results of aiming errors and round dispersions on a bell curve for distance and vector/direction. No getting around that as you said. I don't have a magic "to hit" number. There are 5-6 die rolls for randomizing which is a lot but could be consolidated. I'm not concerned with that right now.

Basically you aim and if your aim error is small, the round has average or less dispersion and you've estimated the correct range to within 15% or less you'll have a 50%+ chance of hitting the target out to about 1,200 yards with a good flat trajectory gun of 50mm+. Tweaking these variables is what I'm working on to get realistic/historical results.

Here is an outline of the process:
1- Place the cross hairs on the target. The "target" is a printed graphic silhouette or line drawing about 3"x3" (can be larger) of the tank type and model in the correct aspect (front, front side 45, side, rear side 45 and rear). There is a square grid overlay on the target with one foot squares. The "crosshairs" is a polar grid protractor, it's a 360 degree concentric circles printed on a clear transparency with concentric circles scaled to the target one foot apart and with 36 lines radiating out every 10 degrees. The cross hairs are at the center of the polar grid. More on that later. Using real line drawings means you get exact hit locations and do not need and size/aspect to hit modifiers. That means no randomized hit location or critical hit die rolls and a minimum of DRM's to look up. I have factored in a target getting hit on the hull top or turret top too.

2- Gunner Aiming Distance Error – Sometimes it's just too hard to get the right sight picture or problems lining up the crosshairs on the target. A trained/experienced crew would have about a 1 mil error, untrained crews up to 2 mil. This is my guess as I have no other data and am open to ideas. This is randomized on a bell curve with a D100 with a slight chance of getting a 2-3x error. The randomization increases or decreases the mil error so it's basically multiplying the base mil number without doing the math (one of my goals). The mil columns are in ¼ mil increments which is fine enough to give 6 inch adjustments out to 1,000 yards (all errors in adjusting the cross hairs are in ½ foot increments, not inches). The final mil error column result can be modified for other environmental, battlefield, crew and equipment factors. The mil error in feet is randomized D100 for 180 degree direction and D6 for left or right side (that covers the 360 degrees). Let's say the aiming distance error is 2.5 feet at 120 degrees right. Now the player moves his "cross hairs" from the desired aim point on the target along the 120 degree line on the polar contractor out 2.5 concentric circles. This is the actual aim point to use in adjusting for round dispersion and range error. The closer you are the better your aim as the mil chart scales to any range with a minimum of math. I hope I communicated that well enough without graphics. My opinion is aim errors are one of the biggest reasons for a shot missing in the heat of combat and it can encompass a lot of the human and non-technical variables. For me the big payoff in the system is being to actually line up cross hairs on a target and see almost to the inch where the round ends up going. I'll stop here for now.

I have a copy of Bird and Livingston's book and McCoys program (but have not utilized it yet).

I get to Santa Monica one weekend a month. I'd be glad to meet with you and show you the materials I have. It will be a one sided conversation as there is most likely nothing you'll learn from me but your opinion and suggestions would be highly valued.

Wolfhag

I take it the humble D6 would not be used and all dice to resolve would be a D100? It would seem more apt to use the D100, and as you say, no magic 'to hit' number to aim for (which would otherwise suggest using a 3+, 4+ etc on a D6)

Cheers, Ark

Ark3nubis,
The D100 is used for randomizing on a bell curve and you pretty much need it for that to represent 100%.

To randomize the angle of an aim point or round dispersion moves I need 19 different variables to represent 180 degrees in 10 degree increments. Then the D6 to determine left or right side. Could use a D10 or D100 but rather than a D6. It's just a 50/50 chance. I'll roll the D100 (2x D10) and the D6 (1-3 = left side, 4-6 = right side) at the same time so it's easier and not confusing. I've tried to eliminate DRM's as much as I can but there are still a few.

The "lowly" D6 is used to generate something that is a 50/50 chance or 1/3 2/3 chance of occurrence. Something it does as well or better than a D100 or D10 and a little easier to use.

Wolfhag

The gunner ranging error is probably the biggest component of error off the target outside of a highly inaccurate round. That you would get from the Bird-Livingston book.

One or two shots and the correction reduces that quite a bit.

Interesting.

The scheme you have outlined, as I understand it, would be right for shooting at a known-range target, but, as Mobius has pointed out, range estimation error dominates the other sources of error for first shots in anti-tank fire. This might not match your intuition based on rifle shooting, because rifle bullets typically have sufficient velocity to "iron out" ranging errors pretty well completely up to at least 300 metres.

As ranging wrrors mater so uch, it makes more sense to treat the errors in a cartesian rather than polar co-ordinate system. This means you would need to generate two random Gaussian variates, one for range and one for line. The gun's ballistic dispersion, collimation errors, pointing errors and all the other stuff in the error budget would apply in both range and line, but the ranging error, obviously, applies only in range.

Incidentally, a guide I have used based on an OR paper that mentioned some trials at Lulworth suggests that the additional expected angular aiming error against a moving target should be about one-third of the angle it can cover laterally during the time of flight of the shot.

I'd be very interested in seeing how your system works in detail, because it seems to me that it could deal quite naturally with the way the balance of advantage between being a hull-down or a moving target changes with range, and how range estimation errors and target movement matter less for flat-shooting high-velocity weapons than for low-velocity flower-pot guns.

Once you've determined the hit location it seems to me you are invetiably into more dice rolling, as both armour penetration and behind-armour effects are stochastic phenomena in real life.

All the best,

John.

John,
Thanks, I'll try to answer your questions. I think it's easiest if I refer you to a trajectory chart and target graphic. I hope this link works
Link: link

Target Description: The target is the front aspect of a T-34 which would be printed out on paper or a chart. Each red square is one foot. There would be a target aspect of front, front 45, side, rear 45 and rear for each vehicle type target. This eliminates DRM's for aspect and target size and hull down representations. The TT and HT arrows are if the target aspect is nose down to the firing unit (or the firing unit has a height advantage) rounds ending up in that horizontal row could hit the turret top or hull top. If the target is nose up to the firing unit the hull bottom can be hit if the round lands in that horizontal row. Not a real accurate way to portray it but what I have right now. Hull down targets are dealt with by giving them a hull down number. On the T-34 a hull down number of 1-5 means that any rounds striking in the rows 1-5 are protected. You can see how hard it is to hit a T-34 turret when hull down. However, when hull down you can aim directly at the turret. Ranges below 200 yards should be treated a little differently.

Polar Coordinate Grid: This has one foot concentric circles and is printed on a clear transparency and the center crosshairs are put on the selected aim point anywhere on the target by the player just as if he would do if he were a gunner. Variables like aim error, round dispersion and range error move the "aim point" of the polar grid transparency in .5 foot and 10 degree increments. Errors are generated using a mil error system and a chance on a bell / Gaussian curve make the error greater or smaller. If the aim error is 1 mil at 1500 yards that's 1.5 yards or 4.5 feet. A D100 is rolled for the aim distance error with about 68% chance of being between 0 and 4.5 feet and a small chance of being out to 13.5 feet (trying to us B&L's method). Another D100 is rolled for the vector/degree of the error. The chart I'm using is supposed to generate an oval with the vertical error being more than the lateral error (one die roll rather than one for vertical and lateral). Let's say the result for the aim error was 2.5 feet at 120 degrees and the D100 was an even number. The aim point is moved along the 120 degree line 2.5 concentric circles. If the D100 number was odd, move to the left, even move to the right. All mil errors are rounded to the nearest .5 feet.

Trajectory Chart: This is my interpretation of the 75L48 Range Trajectory Chart in B & L book. I think it's about 90% accurate and rounded to .5 feet. Let's say you estimate the range and lay the gun at 750 meters on that T-34 target using the aim point in the graphic (5 feet high) but the actual target is at 600 meters (a +25% range long error). Looking at the trajectory chart at 600 going down to the +150 row (600 + 150 = 750) the value is 4 feet so the aim point is moved four feet up at 0 degrees (I'm not using a lateral range estimation error at this point) because of the trajectory set for 750 meters. Yes, the "aim point" is still the same but I'm using it as the starting point for the other random factors. You can see at this new aim point the range estimation error would put the round 1 foot over the turret, a miss. If the target were 10 feet high (like a Panther or Tiger) it would be at the turret. If the firing unit has a height advantage the round could hit the T-34 turret top. You can see why there is no need for aspect and size DRM or hit location roll. Angles hit and penetration are another area, I'm only looking at gunnery right now. I'm not factoring in things like altitude, air temp & density, muzzle velocity variations, barrel temperature variation/warp, ammo temperature, parallax, muzzle jump, barrel wear and ammo batch differences, etc. Give me a break on those.

Other dispersion error factors at 600 meters: The aim error would be about 1 mil for a good crew/gunner (base error of 2 feet randomized 0 to 5.5 feet), the round dispersion would be about .5 mil (base error of 1 foot randomized .5 to 2.5 feet), lateral trunnion error for first shot about .5 feet. I have charts for range estimation errors to 25 yards and a mil error chart in .5 mil increments so I can get enough detail to do errors in .5 foot increments without doing the math. Variables for crew training/experience are factored in by using a different base mil rating for them or column modifiers rather than DRM's. Modifiers shift the mil error column left or right (smaller or greater error) so no math involved. I'm still working on moving targets but it will be based on apparent speed per second across the front of the firing unit and the rounds TOF for the target range with an aim error based on range. The biggest reasons for missing will be range estimation error, aim error and round dispersion if target and firing unit are not moving. Open to other suggestions. There is no point in going into the minute details of all of the variables. The range and mil error charts are each be printed on one side of an 8.5x11 sheet of paper. The gunnery sequence is 5-7 steps printed on both sides of an 8.5x11" sheet easy to read in 12 point type (I'm a senior citizen so can't read small print). Vehicle targets and trajectory charts are separate. Two sheets of paper cover most of the mechanics of the system.

There are drawbacks to the system, other than its length (it's a firing range simulation, not a game). Moving the cross hair 3-4 times will mean manual errors. The final location under the cross hairs will be subject to interpretation (is it really close enough to hit the turret ring?, etc). The math is not as accurate as a computer generated result and the mil charts are rounded to .5 foot increments and range estimation errors to 50 yards so are not exact. The positives for me are that it's easier for me to wrap my head around how variables are influenced using a mil measurement system (like when I shoot) rather than DRM on a D6 or D12 system (that's just me). I'm sure it could confuse other people. It's the only system I've seen that can generate a hit location to .5 foot increments on a realistic 2D target representation. It's my opinion that a round does not hit in a "random" location on a tank. It lands around a random location of the aim point. There is a big difference. It's OK to disagree with me and I'm not going to get into a long discussion about which one is better or a critique of other game systems, use whatever you like, that's what I do. There is no "right" way to do it. I've had lots of fun using a "lowly" D6 with DRM's in a fun and accurate and playable enough game.

This system more or less puts the player in the gunners seat at least from the aspect of being able to put the crosshairs on the exact type of 2D target with the correct aspect and see where the round hits or misses. Not as accurate as a computer but hopefully a step in the right direction for me. If you are close enough or lucky enough you can hit exactly what you are aiming at which can be the hull MG, turret ring, hull bottom as it crosses a hedgerow or bounce a round off the Panther mantlet into the hull top (with some interpretation). None of this is really new, just my approach and modifications of other ideas and game systems. I'm sure others have tried this approach too. I think you can also simulate Battle Sight Setting, Bracketing and even Burst on Target gun laying techniques but that's another post.

Formulas in Bird and Livingston's book are mainly about hitting a 2 meter x 2.5 meter target at a specific range taking into account of all of the variables and I've used them as a basis and to validate my system (really theirs and real life test results with my system and modifications) as I'm not using their equations but am using their research and results as a basis. I'm only concerned about the variables affecting the aim point and then seeing if the ending aim point rests over part of the target – or not. That's why there is no magic hit number or % chance of hitting a target but they could still be generated and my goal is to approach B&L's results and real life test firings as accurate as possible but knowing it's impossible to duplicate tank gunnery 100%.

Wolfhag

The Bird and Livingston formula seems to double count the dispersion value. Then there is dividing the range error (say 25%) by 1.32 (giving 18.94%). Who knows what hat that is pulled from? Now to compensate for less dispersion I use the full range error without dividing by anything.

Plus their std. deviation formula doesn't give the right values.

I found this when a poster over at Matrix hand calculated the 75mm/L48 APCR accuracy. I had to alter my use of the B&L formula accordingly.
link

Mobius,

Thanks. Looking at the T-34 on the link with the three concentric circles: yellow is 16" (about .5 mil), green 27" (about .75-1 mil) and red circle 48" (about 1.5 – 1.75 mil). The mil measurements are from my chart which rounds to nearest .5 feet so it's not going to be exact math. I'm rating most high velocity AT guns firing APC / APCBC rounds with an accuracy of about 1 mil based on test firings, including the German 75L48 but it may be a little more accurate than that. That's 1mil = 2.5 feet at 800 yards on my chart. With my chart and randomizing on "somewhat" of a bell curve a gun with 1 mil accuracy firing at 800m a round has a 70% chance of landing 0- 2.5 feet of the aim point and a 30% chance of landing from 3-4 feet from the aim point, all rounded to half foot increments. It has a 5% chance of hitting exactly where the aim point is. I'm still tweaking and checking these figures with test firings and any other real life data I can get. They seem to be pretty close to the circles on the T-34 link.

I've based my mil accuracy for guns from test firings (not equations) but it's not exact as it's hard to get exact data. The 88L56 gun (HE?) trials show the round getting 98% hit in practice (known range) on a 2m x 2.5m target at 1,500 meters. 2m is 1.5 mil at 1,500 meters which is 6.5 feet on my chart. With the triple deviation (of 50% of the base error in feet) I'd rate that firing at a 1-1.5 mil accuracy and on my chart 97% would fall within 7 feet of the aim at 1,500 meters with 1.25mil accuracy. Does this compute?

The German fire table for the 88mm FLAK 36 firing AP shows a "Means (50% dispersion)" and at 1,000 meters it lists .7m (27.5 inches) vertical. I'd expect the 50% outside of that would be around .8-1.2m giving it about a 1 mil accuracy rating. Using my pre-calculated dispersion charts a 1 mil rating at 1,000 meters would put 45% of the shots within 2.5 feet (30 inches) of aim point with the rest scattering out to 4.5 feet (4.5 feet is 1.5 mil at 1,000 yards). So far it works pretty well but not entirely proven. I haven't run these by anyone else so I need some outside party QA and opinions.

My real challenge right now is generating accurate trajectory tables for guns and different rounds.
The equation he uses on page 165 Appendix 6 "Theoretical Hit Probability" does seem to match up with the 88mm FLAK 18 HE shell from the German firing table for getting trajectory height. I have not tried it out on much else. I need TOF for 100 yard increments which is hard to find.

Wolfhag

Wolfhag wrote:

I'm not factoring in things like altitude, air temp & density, muzzle velocity variations, barrel temperature variation/warp, ammo temperature, parallax, muzzle jump, barrel wear and ammo batch differences, etc. Give me a break on those.

Well normally I would, but…

Variables for crew training/experience are factored in by using a different base mil rating for them or column modifiers rather than DRM's. Modifiers shift the mil error column left or right (smaller or greater error) so no math involved.

…if you already have a scheme for widening or narrowing the expected dispersion, then you can if you wish allow for all the factors in the world, because the great joy of reducing everything to mils is that a mil is a mil is a mil, and any source of error can be expressed in the same currency. Tradition demands that errors in an error budget be combined by the root mean squares method, but a little tabulation will probably handle that without the need to resort to a calculator.

I need TOF for 100 yard increments which is hard to find.

Oh, that's easy, you just need a ballistic retardation program pre-loaded with the drag coefficients from the more popular Gavre drag curves, and I happen to have one of those lying around in Python. The difficulty then is finding form factors for the projectiles you want to include. Still, if you have a few known velocities at known distances, my program will back-fit a retardation series and produce the form factor from that. Finding times of flight to arbitrary ranges at arbitrary intervals then becomes trivial.

And remember, kiddies, this sort of tedious number-crunching of ballistics data is just what computers were invented for, not searching the interweb for pictures of adorable kittens.

All the best,

John.

John,
I downloaded the "Tank Accuracy Model" paper and program. It runs in Fortran 77 so wish me luck on that.
Here it is:
PDF link

The part of the Error Budget I'm most interested in are the random and human errors that cause the round to miss that otherwise would hit.

Round-to-round dispersion is handled by assigning an accuracy value in mils based on test firings.

Range Estimation Error is handled by assigning a base mil error modified by crew type, range finder and the environment. It can be as small as 10% or as large as 45%.

Gunner Lay Error is a base error in mils assigned depending on crew type. It is modified somewhat on type of fire control used, range and gun sight magnification, lighting and how well the target is defined.

Other errors that can be accounted for but are small are Optical Path Bending, air density, air temperature, muzzle velocity variation. I'll use them in the computer formula

Since Variable Jump, Barrel Jump and Projectile Drift is an average difference in dispersions between rounds I assume that would work itself into the test fire results.

Ammo temperature would effect dispersion when taking rounds from the sponsoon and floor which would be cooler than rounds just fired from a turret ready rack and they would hit a little lower at longer ranges.

I'm using Bore Sight as a Parallax Aiming Error. If the gun sight were 1 foot to the left of the barrel and bore sighted at 500 yards at 250 yards the round would hit 6 inches to the right and at 1,000 yards 1 foot to the left. Is that correct?

For Trunnion Cant Error I'm using factors in Rexfords book.

I'm still working out moving targets and wind drift.

Comments and advice appreciated.

Wolfhag

Imagine that, it's in FORTRAN.