Weapons, Damage, and Precision (Part 2)
Posted by Pepin the Short - 21st November 2013
Our last blog post focused exclusively on the considerations one must make regarding a weapon's damage model. However, there is obviously something else to consider when choosing a weapon beyond its damage, otherwise every assault player would be gallivanting about with a SCAR-H. The other question you have to answer is whether or not all those high-damage bullets of yours are going to actually hit anything, so the topic at hand is precision. We'll give precision a practical definition and call it the extent to which the bullets you fire are going to hit your target.
There are two major characteristics of a weapon that affect precision: recoil and spread (the more attentive may have noticed that recoil jitter is a new addition unique to Battlefield 4, but we can talk about that later). Recoil in Battlefield has both horizontal and vertical elements, and it is otherwise defined, when you are looking at a weapon's description in Battlelog, as stability. Spread, or accuracy, is the measure of where the shots are likely to go relative to your point of aim; just as in true-to-life weapons, having your sight lined up on a target doesn't mean that the bullet is going to fly straight and true.
Rather than trying to explain what recoil and spread are and what they do, we'll walk you through an image you'll commonly see on Symthic: the Accuracy Plot, shown here with the AK-12 and the heavy barrel.
First, what this plot is showing you is a series of five-shot bursts from the AK-12, with green representing the first shot, yellow being the second, and so on. If you sat down with the AK-12, aimed at the wall, and fired a hundred five-shot bursts without any attempt to control the recoil, a pattern very much like this would emerge, exposing the mathematical behavior of recoil and spread in Battlefield.
The first and most obvious characteristic of this image is the vertical recoil. With the exception of the first shot, the recoil between each shot is constant (0.45 degrees per shot here), as seen by the constant distance between the center of each successive shot pattern. The most remarkable gap is between the first shot and the second, which is effected by the 'first shot multiplier,' or FSM. The AK-12 has an FSM of 2.1, which, compounded with the heavy barrel recoil multiplier of 1.5, results in a whopping first shot recoil of 1.42 degrees.
Attachments that affect recoil and spread all have multiplicative effects. So, for example, an AK-12 with the heavy barrel and the angled foregrip will have a FSM of 2.1, a recoil multiplier of 1.5, and a FSM modifier of 0.67, resulting in an ultimate FSM of 2.11. Again, I encourage you to visit the Weapon Multi-Comparison page to see how various attachments affect various weapons.
The second characteristic of this plot you may notice is the spread. Recoil simply pulls your point of aim upwards; however, with each successive shot, the circle of likely bullet placement gets larger. This is because weapons have not only hipfire spread, but ADS spread as well. The base spread of the AK-12 with attached heavy barrel of 0.1 degrees is seen in the green circle representing the first shot.
This spread is created by a circle drawn by measuring 0.1 degrees in any direction from your point of aim. (For the mathematically-inclined among us, that gives your spread a solid angle of 0.03139 steradians.) This, of course, means that spread is going to have a greater and greater impact at greater and greater distances.
Weapons also have a characteristic called 'spread increase,' which increases the size of that circle by some number of degrees per shot; this is why all weapons in Battlefield get progressively less accurate as you hold down the trigger, and why it's almost always a good idea to fire in bursts. There is, as well, spread decrease, which returns your weapon to its original spread when you stop shooting. So you appreciate the magnitude of these values, the spread increase on the AK-12 is 0.085 degrees per shot, while the spread decrease is a tremendous 15 degrees per second.
You don't have to wait too terribly long between bursts for maximum accuracy.
You may also notice that the spread circles are more elliptical than circular. This is because of the horizontal element of recoil. Vertical recoil pulls straight up, but horizontal means that, after a shot, the reticle can land anywhere along a line given by the angle of the horizontal recoil. The AK-12, for example, has horizontal recoil of 0.15 degrees to the left and 0.1 degrees to the right. This means that it will generally pull to the left, as seen in the accuracy plot. However, because where the recoil will move is completely random within those parameters, the weapon will not pull in that direction the same way every time.*
While vertical recoil can be compensated for by pulling down on the mouse or the joystick, horizontal recoil and spread both add an element of randomness to a weapon, which is exacerbated the longer you fire it. Therefore, to be as precise as possible in Battlefield, one must be controlled and patient when firing your weapon, and choose weapon attachments carefully; many attachments will make one quality of a weapon better at the expense of another.
The advantages and disadvantages of different weapon attachments is something we can cover later, but, for now, you can see the effect they have on a weapon's spread and recoil yourself by comparing weapons and attachments on the Weapon Multi-Comparison page. Everybody plays Battlefield differently; find out for yourself whether you want good damage, controllable recoil, or low spread in your weapon.
Pepin the Short
*The exact behavior of horizontal recoil is still a matter of some debate. In generating the Accuracy Plots, we assumed it works in the way described. If you have any insights to share, feel free to discuss the topic on our forum, or leave a comment below.