firebugs

Rifle ballistic coefficients

22 posts in this topic

Mostly a place-holder. I have 5-7 years of long-range shooting experience both in the Marine Corps, and outside of it in competitive long-range/precision shooting. Additionally I own (at least some variant) of many of the rifles and munitions used in this game. This post is in the interest of realism and historical accuracy because I believe that is one of the key points of the game and every attempt should be made to have these weapons perform as they did (do) in the real world.

Current G1 ballistic coefficients (either info given to me by GOPHUR or what I've found via testing).

K98k/G41/G43- .210

No.4/Bren/.303 aircraft and co-ax brownings- .251

MAS 36/MAS40/FM29/7.5x54mm aircrat and coax MG's- .309

MG34/Fg42 and coax/plane 7.92x57mm MG's- .31ish (tested only)

M1903a3/M1903a4/M1 Garand/BAR- .20ish (tested only)

Obviously there is some disparity here as the ballistic coefficient is bound purely to the bullet (and is somewhat dependent on its velocity, but for what I'm talking about, the difference in velocity between two different weapon platforms firing the same ammunition has a pretty negligible effect on ballistic coefficient difference). So we have, for example, the K98k, G41, G43, Mg34, and Fg42 that all fire exactly the same ammunition (same bullet), but have two drastically different ballistic coefficients being used-- Both of which are entirely too low.

In fact, everything listed above excluding the 7.5mm French stuff is absurdly low. The effect is that the bullets shed energy (velocity) faster and faster than they should the farther they fly. This means impact energies are lower than they should be for all ranges beyond point blank. Bullet drop and bullet flight time is exacerbated for all ranges beyond point blank. I will continue to add information to this post as I get time, and at some point I would like to begin real-world testing with original era ammunition and/or components at some point to prove my theory.

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So apart from the bullet drop, I take it the other in-game effect would be the lethality of rifle based ammunition?

What I trying to say is, it's pretty rare for an inf to get shot by a rifle round (whatever the source) and survive. Would the increased lethality really be that noticeable?

Still, bullet drop is reason enough to correct it though.

One other thing to consider is that the world map is 1/2 scale. Maybe they intentionally used low ballistic coefficients to offset this?

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So apart from the bullet drop, I take it the other in-game effect would be the lethality of rifle based ammunition?

What I trying to say is, it's pretty rare for an inf to get shot by a rifle round (whatever the source) and survive. Would the increased lethality really be that noticeable?

Still, bullet drop is reason enough to correct it though.

One other thing to consider is that the world map is 1/2 scale. Maybe they intentionally used low ballistic coefficients to offset this?

Flight time and trajectory are the biggest things here.

Also consider early tier aircraft where the primary (only) armaments are .30 caliber machine guns.

Light/medium vehicle armor penetration (say from nearby riflemen/LMG's) will be practically unaffected. Muzzle velocity and bullet weight will not be changed, so if it doesn't penetrate at point blank now, it won't penetrate with an increased ballistic coefficient. If it penetrates at 50m and closer now, it may penetrate at 57m and closer with an increased ballistic coefficient. If it penetrates at 200m and closer now, it may penetrate at 350-400m etc.. etc.. The further away, the bigger the "growth".

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Here are some estimates as to the ball-park numbers we should be looking at.

.303 british Mk7 Ball- .390-.420

.30-06 M2 Ball- .360-.380

7.5mm ***** C- .300-.340 (again, this one is already close enough that I can't tell by the testing I was able to do before (without more tools, basically) that it's "wrong".

7.92x57mm Gewehr Patron sS- .520-.565

And the Lebel's 8mm ***** D, which is currently around a .230 or something thereabouts, should also be close to the german 8mm, mid .4's to low .5's. I've had trouble finding info on this caliber in the past.

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i read long ago all rifle ammo used in game is AP, maybe that's why?

Potentially, if armor penetration was used as the genesis of determining ballistic coefficients to be used. Essentially, the game treats all "ball" ammo like it has a hardened steel core. In this respect it would yield abnormally high penetration results in the game at range, and would require lower ballistic coefficients to achieve historical penetration data of deforming lead (Pb)-core ball projectiles.

However, much has been "tweaked" over the years to prevent infantry and aircraft from achieving armor kills through thin top/bottom armor plates.

Again, if a weapon system does NOT penetrate now at point blank, changing the ballistic coefficient to 1 million would not make it penetrate-- the game uses mass, velocity and impact angle, not BC to determine if a penetration occurs.

The only instances you may see more penetration at considerably longer ranges may be in thin-skinned vehicles like trucks or aircraft where bullets may meet certain thresholds (say starting a fire in a fuel tank for example) at longer distances.

What exactly would be changed and how far out, I can't know without knowing exactly what the threshold is so that I could run the numbers with the higher BC's.

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I think it's a function of the map. It's a half scale map of Europe so the bullets only go half as far. :)

-Irish

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Hello All.

As has been previously pointed out the map/ground scale is 1:0.5. The visual scale appears to be 1:1. I suspect this is the core reason why HE is ineffective, simply because of the differences between the computations scale (ground scale 1:0.5) vs the display scale (visual scale 1:1). I.e. a HE weapon that has a kill radius of say 10m calculated, would visually need to be within 5m to achieve the same result. How often do you see comments in the chat “I have to almost hit them for HE to work”. Might I point out there has been a recent HE Audit to address this very issue.

Additionally any calculations based on visual interpretation of in game actual displayed measurements are likely to be adversely affected but the mismatched scales as well.

How to test this theory for different scales for the calculations and display scales, as it is only a theory. Using a distance tally usually displayed for an origin point (Spawn), move till the tally says 50m away. The length of a common Olympic pool. Look at the displayed distance. To me it only looks about 25m, either way defiantly not 50m. I find the best target building for the test is the FB Vehicle spawn. Its height can easily be estimated by comparing various vehicles sitting inside it. From that its width and depth can be estimated.

Just my theory. It is not entirely out of the bounds of possibility the vertical scale has similar issues as well.

Cheers

James10

Edited by james10

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Totally separate issue, but no guys. The scale of the map relative to the real terrain isn't the issue here.

There's no ballistic compression going on--- the map is just smaller than the real thing. Neither HE fragments, nor bullets are adversely affected by the map scale.

Plugging in the given muzzle velocities, bullet mass(es), and give/tested G1 ballistic coefficients gives exactly what one would expect from a G1 calculator such as www.jbmballistics.com, or there's one on www.hornady.com . Bear in mind when using the above that there is a 9-10% difference between yards and meters, and it DOES matter.

The map scale does not affect altitudes (airplanes), ballistics, fuel consumption, etc. etc... You just have half as far to go between cities/towns.

Again, separate issue and doesn't play a part here.

Edited by firebugs

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Hello firebugs, how are you today?

Totally separate issue, but no guys. The scale of the map relative to the real terrain isn't the issue here.

There's no ballistic compression going on--- the map is just smaller than the real thing. Neither HE fragments, nor bullets are adversely affected by the map scale.

Plugging in the given muzzle velocities, bullet mass(es), and give/tested G1 ballistic coefficients gives exactly what one would expect from a G1 calculator such as http://www.jbmballistics.com, or there's one on http://www.hornady.com. Bear in mind when using the above that there is a 9-10% difference between yards and meters, and it DOES matter.

The map scale does not affect altitudes (airplanes), ballistics, fuel consumption, etc. etc... You just have half as far to go between cities/towns.

Again, separate issue and doesn't play a part here.

Thankyou for your speedy reply.

Everything you say is completely correct in regarding the “The scale of the map relative to the real terrain isn't the issue here.” I have absolutely no arguments here.

The specific point of my post is:

I suspect the in-game ground/map scale is different to the in-game visual/display scale.

1m as displayed is calculated as 2m map scale.

Now if you have done any testing in-game to calculate the BC of anything, those numbers will be affected by the difference (if it exists as I suspect). Measurements you “See” in-game is not necessarily what the system will display and use for its calculations.

In-game Map/Ground scale 1:0.5. – In-game appears to be Visual/Display scale 1:1.

If you were able to accurately measure and display the height of the generic modelled solider in-game I suspect the generic solider would actually be measured at 4m high and NOT what I would expect being 2m, according to the in-game ground/map scale. The HE issues I feel are potentially just an indication of the differences in scales.

If you are able to categorically state there is no differences, I would still say “are you absolutely sure. What is your proof?”

I am not talking about Map scale vs Real Terrain. I am suggesting the in-game calculation scale is not the same as the in-game visual scale. In short in-game, “What you see, is not what you get”. "

"If" what I suspect is true, it will potentially play a BIG part here. If its not, then all is fine and dandy.

Once again thank you for your time.

Cheers

James10

Edited by james10

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I was actually kidding. Note the smiley after my text.

Still, can someone spawn into offline training and clone something such as a truck, a number of times, end to end? If we know the length of the truck and can tell how many "truck lengths" there are, it -SHOULD- match the distance between the player's avatar and the target in question. If not, there might actually be something to that idea.

-Irish

Edited by odonovan1

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Hello odonovan1, how are you today?

I was actually kidding. Note the smiley after my text.

Still, can someone spawn into offline training and clone something such as a truck, a number of times, end to end? If we know the length of the truck and can tell how many "truck lengths" there are, it -SHOULD- match the distance between the player's avatar and the target in question. If not, there might actually be something to that idea.

-Irish

My thoughts exactly, eventually.

I was considering using a French Char 1B as I think its the longest vehicle in game. The target would be a placed fru.

The fru would the placed then the first of several Char 1Bs would be placed with tracks touching the fru. Additional Char 1Bs would be placed end to end with tracks touching tracks. Once in position the Infantry spawned from the fru would move to the rear of the last Char 1B and directly read the distance from the tally. As long as it wasn't over 200m it should display.

2 screenshots would be required. One shot of the overall chain of vehicles including the infantry and fru at either end. The other screenshot would be what the infantry at the end sees including the "Origin" tally including the distance only in meters though.

The length of the Char 1B is known. The distance displayed should be the same approximately as the caulculated length of the several Char 1Bs. If not there is imperial evidence.

Cheers

James10

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I understand what you're saying. What I'm saying is it's not the case.

I tested the BC's independently from CRS at first. This was done using a "real" ballistic calculator that gives data that I could use target shooting down the road from my place and was based off of impact energies recorded in a version of an open BETA test server (almost none of the small arms ballistics stuff has changed since day 1, so there's no version A vs. version B going on).

I tested at point blank and the energy outputs matched the muzzle velocity and bullet mass +/- the muzzle velocity dispersion CRS incorporates into every round fired. They matched exactly what would be expected.

Then I stepped off every 100m in the game and fired 100x shots recording each to give an average (for each weapon system out to 500m, sometimes further). That average impact energy was then used to back-solve a ballistic coefficient using the bullet mass/ MV I have and know the game is using.

The BC's I found using this method work and were all within about 10% of what CRS finally gave me when I requested to know what they were using (they gave me some, not all).

So that tells me 1m is 1m in the game to a reasonable degree. The map being 1/2 scale is more a logistical thing... 1/4 the terrain work to do, much less distance between bases (less boring drives/movements etc.. more action). That's why I say the map is a separate thing. Geographically it's smaller than the real world, but 1m is still 1m. Like if you're used to driving a Suburban and I put you in a smart car. You're still 5'10", you just have less room to move.

DOC has stated this before, as well as the fact that the air/altitudes are 1:1 scale to maintain historical aircraft performance.

My last comment on this is that the map isn't always 1/2 scale. It varies considerably because it's a big flat sheet (no curvature), so changes in latitude change the scale ratio considerably. For this to have some sort of effect on ballistics would cause so much wonkiness it would make my head spin and I wouldn't likely be able to conduct any of the testing I have done so far. It just doesn't play a part.

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Hello firebugs how are you?

...

Then I stepped off every 100m in the game and fired 100x shots recording each to give an average (for each weapon system out to 500m, sometimes further).

...

Would you be able to clarify something for me? When you say “I stepped off every 100m” how did you ascertain that you were at 100m in-game? Did you “eyeball it” or did you have some form of distance display generated by the game and displayed to you in-game?

Cheers

James10

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Waypoints, the map, and range finders from various vehicles. Much of it was also done on the "Area 51" firing ranges at marked yard lines.

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Thank you for that.

Waypoints, the map, and range finders from various vehicles. Much of it was also done on the "Area 51" firing ranges at marked yard lines.

Cheers

James10

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Technical Intro and Caveats:

There are some caveats that I need to get out of the way before I start dumping technical information here.

1) Units... I will for some examples use grains, sometimes grams, m/s, fps (ft/s), and potentially others if I need to.

Grain--> gr

Gram--> g

Meters per second--> m/s

Feet per second-- > fps or ft/s

I think most people know what feet, meters, and grams are. Grains, maybe not. There are 7000 grains in 1 pound.

1 grain = 0.0647989 grams

I'll do my best to present things so that grains and grams don't get mixed up.

2) Ballistic coefficients... They are used in a series of formulas that are somewhat "backwards" to traditional physics-- for example a higher ballistic coefficient means the bullet is more aerodynamic, but a higher coefficient of drag (traditional physics) means the bullet is less aerodynamic. Think of ballistic coefficients (I'm going to start calling them "BC's" to abbreviate) as a measure of how well an object (almost exclusively used for bullets) flies through the air. They are almost all decimal numbers (for small arms projectiles), but there really is no "limit". They can meet or exceed 1.0. The BC is tied to the projectile-- it describes that SPECIFIC projectile's ability to cut through air at a specific velocity range. It can change-- drastically-- between two bullets of identical diameter and mass, so it's not like "all .30 caliber bullets are 0.XXX" there's a wide range for every caliber.

Some examples of BC's from manufacturer's published data.

9mm 115gr FMJ- 0.127

5.56mm 62gr FMJBT (M855 current issue military projectile for M4/M16)- 0.304

.308" 147gr FMJBT (typical of current military issue 7.62x51 ball)- 0.398

.308" 175gr HPBT (What is currently issued to US military snipers)- 0.505

.510" 802gr Copper Solid low drag projectile (.50bmg "sniper"/precision bullet)- 0.950

The above are just to give you an idea of the typical spectrum available in small arms projectiles. The heavier and more aerodynamic the shape, the higher the ballistic coefficient. I may delve into this subject deeper later on, how different shapes affect BC... but not now :)

Now for the caveats... Being that BC's are a measure of how well these projectiles fly through the air, and air can change considerably in viscosity, density, temperature, etc. from season to season, day to day, even hour to hour, AND the drag induced on the bullet changes constantly as its velocity changes going through the air, the listed number for a BC is not gospel. It describes ONE condition. One air density/temp/humidity level and one velocity.

The point isn't necessarily that they aren't accurate, just don't get hung up on "Well, the listed BC is .304 so why are you saying you got .297?". There's some variance, but nothing extraordinary. Remember a few posts back when I said I couldn't really tell if the French 7.5mm stuff was definitively "wrong" or not? This is why.

We are also greatly helped in the game insomuch as that the game uses ONE single set of "environmental" (pressure, temp, humidity, etc. etc.) data that never changes.

Later tonight I will see if I can drudge up some graphs and pictures to better explain how velocity affects BC, and why the variance really not a big deal for what I'm doing because we rarely ever approach the trans-sonic range of any of these projectiles.

I think that's a good stopping point for now. Certainly more to come-- I'm just trying to lay down a foundation so that everyone reading this can "kind of" understand what's going on instead of being lost in vocabulary asking questions that aren't relevant. ;)

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G1 Ballistic calculators...

For a more in-depth read, https://en.wikipedia.org/wiki/Ballistic_coefficient

For an even more in-depth understanding specifically to small arms and long range performance, I suggest picking up Bryan Litz's book, "Applied Ballistics For Long-Range Shooting".

Without getting too technical, ballistic calculators are programs or apps that use formulas that have their origins in the late 1800's. They take several inputs and produce a predicted trajectory. For the type of shooting and competitions that I do, obviously you want the calculated trajectory to match the real trajectory of the bullet as closely as possible. So, there are different types of calculators (see the wikipedia article for more info) for different types of bullet shapes. They use an "ideal" projectile with a BC of 1.0 (again, BC's can go over 1.0, especially in G1 calculators-- the "ideal" part of it may be a misnomer) in various shapes. G1's ideal projo is a fairly blunt artillery shell looking thing, G6 is a flat-based spitzer, G7 (what I use a lot) is based off of a 7.5 degree boat-tail bullet with a very pointed tangent ogive (nose).

So what happens if I try to fit a VLD bullet into a G1 ballistic coefficient (use the "wrong" calculator type)?

Not a lot. The G1 system, which is fairly universal-- almost all published BC's are in G1, unless otherwise stated-- is really pretty robust for most projectiles and provides data that is very accurate to a point. That point is the trans-sonic region. When bullets approach the speed of sound (because they're constantly slowing down in air), there can be some divergence between the true trajectory, and the G1 calculated trajectory.

It's not a big deal, however, because typically that is 800-1500m away from the shooter, and not a whole lot of shooting is done at those ranges (except for guys like me, and we make up a small minority of shooters). As it pertains to WWIIOL, infantry only render to 700m (last I looked), and the sights only go to 1000m on infantry weapons.

What am I getting at here? The G1 system that the game and most ballistic calculators use is fine for what we're trying to accomplish-- an accurate representation of historical performance. The game uses a G1 system with (what should be) G1 ballistic coefficients, and it uses it for all projectiles, regardless of shape, mass, caliber, etc... And that's OK.

G1 BC's are not at all interchangeable with G2, G3, G5, G7 etc. etc.. ballistic calculators. Each type of G# calculator has it's own BC's. I'm just stating this as a warning that you can't plug a G7 BC into a G1 calculator and get accurate data, and visa/versa. It will be completely wrong. For example, a 6.5mm bullet that I shoot has a 0.626 G1 BC, and that same bullet has a 0.305 G7 BC. Obviously the scaling is totally different between G1 and G7 and you'll get garbage info back if you mix them up...

Speaking of ballistic calculator inputs... Different apps have different options, but the bare-bones inputs that are necessary to get good data back are;

Muzzle Velocity

Projectile mass (for energy)

Ballistic Coefficient

Sight height over bore (how far above the bore centerline the sights are)

Temperature

Air pressure

Humidity

The last three there in some calculators can be cobbled together as "Density altitude", one value that represents air density and replaces those three lines. My guess is that CRS is using a "standard" sea-level temp/air density value, but I could be wrong. Air density can change trajectory considerably, but as far as I know, in WWIIOL it's the same at all positions/altitudes (otherwise at higher altitudes, you'd notice that impacts were higher than the sight settings represent... and I have not noticed that trend).

What I'll be using for Temp, pressure, and humidity for WWIIOL calculations is 59 deg F, 29.92 inHg, and 0% humidity.

Next up (tonight or tomorrow probably), I'm going to go over different bullet constructions, shapes, profiles, etc... and how it relates to BC, and why.

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Ok, back at it a little today. Life caught up with me and I forgot about this stuff for a bit :D

Most military bullets are going to be FMJ (full metal jacket) construction. This is true for all of the small-arms projectiles used in WWIIOL-- another word for plain-jane FMJ is "Ball". Full metal jacket means just what it says. There is a copper, copper-plated steel, or copper/nickle alloy jacket surrounding a solid lead, or a mixed core of lead, steel, wood, and/or aluminum. Russian 7.62x54r ball, for example, has a copper-plated steel jacket, primarily a mild steel core (no AP ability), and a lead plug behind the steel.

Prior to WWI, most modern armies switched over to "spitzer" projectiles. Spitzers are just pointed more than the previously used round-nose projectiles. The pointyness cuts down on drag, and increased ballistic coefficient considerably. All of the rifle/lmg/ATR projectiles in WWIIOL were of spitzer designs by the time WWII rolled around.

On the back end of the bullet, there were (are) two main types of bullets. Flat-based, which is exactly what it sounds like, and boat-tailed. The boat-tail bullets have a tapered rear-end that maintains laminar flow of air past the bullet longer, and also serves to reduced the diameter of the flat part on the far rear of the bullet, both of which reduce drag and increase ballistic coefficient.

Some bullets also have a groove cut for crimping the brass case into the bullet called a cannelure. Crimping is done to prevent the bullet from sliding in the case, moisture protection for the powder, and can have some beneficial effects on muzzle velocity spreads. That said, it does very slightly reduce BC because it creates a little bit of drag.

Here is a cross-section of a 3d model I made of a bullet that is roughly a Mk7 ball projectile used in the Lee-enfield with labels of the different parts.

mk7slice_zpsowwi2w71.jpg

This is a generic FMJBT model with some more labels

fmjbt_zpsu0xdhjh4.jpg

So a quick list of what the game uses and it's construction/type.

M2 Ball (M1, M1903, BAR, US .30 cal MG)

.308" Diameter

150 grains

Full metal jacket, flat base

Lead core

Mk7 Ball (.303, Bren, Lee Enfield, .30 cal brit plane/tank coax MG's):

.312" Diameter

174 grains

Full Metal Jacket, spitzer flat base

Lead core with wood or aluminum in the nose

Ball C (7.5 French, MAS 36, MAS40, FM29, tank/plane MG's)

.308" Daimeter

139 grains

Full Metal Jacket, spitzer flat base

Lead core

Ball N (8mm Lebel, sniper)

.323" Diameter

198 grains

Full metal jacket, spitzer boat tail

Lead core

SS Patrone (K98, MG34, Fg42, G41, G43, Panzer and LW MG's)

.323" Diameter

196 grains

Full metal Jacket, spitzer boat-tail

Lead core

More later. I own a few hundred 7.5mm Ball C, SS Patrone, M2 ball, and Mk7 ball-- My intent is to eventually test fire them at various ranges (real-world) to back-solve a ballistic coefficient for each of the bullets that I can.

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Before I get into testing these bullets, I'll recap and outline a few pointers.

1. The game uses a G1 ballistic calculator for trajectories in-game. G1 calculators use muzzle velocity, bullet mass, and ballistic coefficients to generate trajectories and impact energy numbers.

2. G1 ballistic calculators, within the super-sonic region of a bullet's flight correspond EXTREMELY close to the actual trajectory of small-arms bullets.

3. The muzzle velocities and bullet masses are correct via repeated testing I have done previously. What I have a hunch about is that the ballistic coefficients are low. This is based off of some documentation (military pub with .30-06 M2 ball ballistic data), original weapon sight settings, and my experience shooting at long range with original era weapons & ammo, as well as similar calibers of newer manufacture.

4. Ballistic coefficients are tied to the bullet. This means I can pull 7.5mm French bullets, and shoot them out of a .308 winchester rifle at similar speeds, and based on the trajectory that the bullet takes, can back solve the same BC that would be found if I had shot it out of a 7.5x54 French rifle.

5. I have several thousand-dollar optics and rifles that I can fire most of these bullets out of (excepting the 8mm's, unfortunately) that will produce more precise trajectories than the original rifles, which can be tracked positively to within 0.004 degrees.

I have weather meters that give me barometric pressure, temperature, and humidity, allowing me to take into account all environmental factors that affect rifle bullet trajectories.

I have a chronograph that is accurate to within ~3m/s or 10fps that will let me both see what the original ammunition in the original rifle had for muzzle velocity, as well as track each shot in a newer precision rifle to more accurately back-solve for BC.

So here's my plan for testing.

Pull Ball C, Mk7 ball, and M2 ball bullets from original military ammunition.

Load those bullets into match-grade Lapua .308 win cases with a powder charge to mimic original muzzle velocity for the given projectile.

Confirm an exact 100m zero for the .308 rifle and optic.

Fire the rifle at 600-800yd on a large target backer to determine the exact adjustment necessary to compensate for the given distance, noting all environmental data, and recording muzzle velocities.

Use www.jbmballistics.com to back-solve a ballistic coefficient using the data collected on the range.

Using this method will give CRS the exact information needed to adjust their BC numbers for historical trajectories and energies over distance.

At this point I'm only able to do the .30 caliber stuff, but may be able to do 8mm in the future.

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Things are coming along slowly but surely. Here's a picture of some of the original WWII era bullets pulled out of their cases.

lineup_zpsoua9hqp3.jpg

The three .30 cals I'll be able to load into a .308 winchester casing and get some useful data out of. The .303 british bullets are .312" or so in diameter, so they'll experience a bit of a squeeze but nothing too drastic. About half the thickness of a sheet of paper diametrically. The German 8mm stuff is too big to shoot in a .308 bore. Physically won't fit into the chamber, and even if it did, the change between initial and final diameter is big enough that I wouldn't trust the BC results from it (assuming it shot accurately enough to test).

What I'm thinking for the actual test is that I'm going to zero the rifle for the given bullet at 100yd. Then I will shoot a 10 round group at 100yd to verify exactly the point of aim (POA), and point of impact (POI) relationship. I will take note of it, but won't correct for it.

Then I will shoot at a 4x4 foot target backer with estimated elevation adjustments at 600yd (I may shoot on a steel target first to get me in the ballpark). This will be either a 10 or 20 shot group because odds are it's going to be a couple feet wide. The more data points there, the more accurate the exact center of the "cone of fire" can be pinpointed (there's software specifically for this).

All told I should be able to get the data I need with 30-45 rounds of each bullet.

What the testing will give me is exactly what angular deflection is required to change my POI from 100yd to 600yd. I will have the muzzle velocities, temperature, humidity, barometric pressure, scope height over bore, and bullet mass which will allow me to back-solve the ballistic coefficient of the bullet.

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...all this equipment yet hes playing w a connection dating back to the Carter administration hence the name "firebugs"...

Yeah, we chatted some way back then and you started this years ago already but seemed to have hit a brick wall back then - gj, make them fix it finally - carry on

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