There is not a lot of information out there on VATS and how weapon Modd impacts it. So I ran a few tests to figure out how weapon mods impacts.

First, by using the console command player.setav actionpoints XX I was able to determine the exact AP impact a certain mod was having. I changed my AP until I had enough for exactly 1 shot. This gave a very precise number.

I also used the hunting rifle as my base. The base AP of a normal hunting rifle is 26. I then tested various mods. The various mods all seem to add a flat modifier to the AP cost.

Receivers:
Light Framed: dropped AP cost to 19
Heavy Frame: 33 AP
Celebrated, hardened and powerful left AP at 26

Barrels:
Long Barrel: +5 Ap
Light versions: -2 AP
So a long light barrel only raised AP by 3

Magazines:
Medium mag: +4 AP
Large mag: +6 AP
Quick eject mags applied -2 AP to the above

Stock:
Full stocks: +5 AP

Scopes:
Glow sites: -2 AP
Reflex site(either version): -4 AP

a powerful receiver with a long light barrel a std quick eject mag, no stock and reflex sites has an AP cost of 23. Which is pretty darn good!

Preliminary testing with other weapons shows the same thing. Reflex sites and quick eject mags really help. And avoid the stock whenever possible

nice to know!

The question is, what do you want more? An extra VATS shot or two, or fewer VATS shots that are more powerful, accurate, etc. Since I always put good points into Agility to boost AP with any guns character, I've never had any problems with not having enough AP. Putting 2 points into Action Boy/Girl pretty much puts the nail into any AP concerns, anyway. Cutting back on all the other good weapons mods just for the sake of having a few more VATS shots, makes no sense to me.

I agree, it is all about finding the right balance. But a powerful, long barrel, large mag, full stock hunting rifle has an AP cost of 42. But has the same accuracy and damage of a hunting rifle with powerful, long light barrel, std quick eject mag and reflex sites. But that rifle only costs 23 AP. a pretty big swing!

So no test with actual scope types (the mods that I think cause the largest delta)?

The fact that a stock slows you down is utterly insane. It's bad enough that heavier weapons shoot slower when the exact opposite is true in reality, but I can accept that as a game balancing decision. More powerful = more weight = slower. But since rifle stocks exist to make shooting faster, making them slower in game is a truly strange choice.

Rifle stocks exist to make shooting more accurate, not faster. And a stock does weigh more than a pistol-grip butt, by a little bit. But in reality, the only thing that should slow your character down much is going from rifles to a heavy weapon of some sort.

That's not really true at all. The added weight of a stock can make shooting easier by stabilizing the platform and the shape does make it easier (and faster) to form a good sight picture, but if speed were not an issue a pistol could be just as accurate as a rifle, given similar barrel length. (See the T/C Encore line of rifle-caliber pistols.) But that pistol would be SLOW.

APs are simulating shooting speed, which is only really relevant if you're shooting more than once. Once we're in the realm of semi-autos and not talking about manually cycling a bolt-action, the limiting factor for following shots is how quickly you can get the gun back on target. The enemy of that is recoil, and anything that mitigates recoil makes for faster shooting. The game gets this right with compensators, but wrong with the weight of guns and the physio-mechanical effects of adding a stock. Compensators use gasses from the ignition to apply counter-forces and keep the barrel from rising and/or pushing back as much as it otherwise would without the compensator. Heavier objects simply have more inertia and aren't moved as much by recoil. Shooting a long gun positions the body in such a way that it absorbs recoil better and transforms the moment of that recoil into a "push back" rather than a "rise up". It also locks the face and eye to the weapon so that it moves with it during the recoil impulse. All of those things reduce the time it takes to get back on target. Improving targeting helps too, of course. So we have glow and reflex sights. (Why don't we have laser sights in FO?)

So in a long stock over a short one we have 1) increased weight 2) better physics and 3) better sight picture. All of those things combine to make a rifle vastly, incredibly faster than the same round in a pistol configuration. There are many real rifles which shoot pistol rounds with which you can test this out, and the bigger the round the more stark the difference. For example with a middling powered 9mm Glock 17, I can do the first two shots in about a second (a "double tap") but they get progressively slower as the string progresses for an average of about 1 shot per second. OTOH, I have a 9mm carbine with a stock that weighs 3 times as much with which I can fire 10 rounds in about 3 seconds. For real fun, switch that to a pistol grip 12 ga shotgun! Those are otherwise known as wrist-breakers

So the game basically gets the whole concept of weapons speed exactly backwards, with the exception of the compensator. It's not surprising, though, given that the engine was first designed for mostly melee weapons which ARE slower when they are heavier or longer. I think they just re-used the mechanic from Skyrim.

I will post some scope details latter on. But scopes seem to make VATS horrendous. Better to carry a scope rifle for free aim and a stripped down light version for Vats.

As for rifles vs pistols I think it is more a balancing act/game design. If rifles beat pistols in every category, who would use a pistol?

That's a very good point, people carry pistols IRL because they don't have the Sole Survivor's magical Bag of Holding, but everybody - and I do mean everybody would prefer to have a long gun if they knew they were going into combat (exempting caliber considerations). Making pistols faster does give them an advantage to make up for their lack of accuracy so they're more "balanced" for gameplay.

Still, I think that might be giving the devs too much credit. I still think they just used the melee mechanic.

Ironically, the scope thing does make sense because they slow down aiming immensely. They see such a small "slice" of the world that even a small shift due to recoil is likely to move the target completely out of the scope's FOV so you have to "find" it again.

I had suspected weight was a factor in AP, and now this confirms it. Having a lighter weapon also increases aiming speed.

Since AP is reduced on combat armor modding to lighter builds, it makes sense it would work for weapons too.

Thanks for taking the time to let us know.

There is a mod: 'better weapon mod descriptions' witch shows exactly how vats shots are affected, by percentage, in real time when you mod a gun. Really helpful.

Yes, but I am trying to stay away from mods until the geck is released.

So for scopes:

Short: +8 AP

Medium: +11 AP

Long: +14 AP

It does not matter if it is a plain scope, night vision scope or recon scope

Lastly the 50 cal receiver has no impact on the AP use. It stays at a base 26

Using scopes is a big no-no with VATs. I plan on keeping one fully tricked out sniper rifle and using a more tactal low AP rifle for VATs usage.

After all, we do have the magical bag of holding! Why not lug around 5-6 rifles.

Yes, scopes helps a lot for longer range vat shots. VAT is very nice if you get jumped with an sniper rifle, no its not primary an vat weapon but say you snipe supermutants and an suicider comes charging around an corner.

Accuracy at medium ranges are also important.

I have the mod in question, so I just went and pulled the values for all Hunting Rifle mods that affect AP cost. They are as follows:

Light Frame Receiver - AP Cost -25% (19.5)

Heavy Frame Receiver - AP Cost +25% (32.5)

Tuned Receiver - AP Cost -10% (23.4)

Short Barrel - AP Cost -10% (23.4)

Short Light Barrel - AP Cost -15% (22.1)

Long Barrel - AP Cost +10% (28.6)

Long Ported Barrel - AP Cost +10% (28.6)

Full Stock - AP Cost +20% (31.2)

Marksman Stock - AP Cost +20% (31.2)

Medium Magazine - AP Cost +5% (27.3)

Large Magazine - AP Cost +10% (28.6)

Quick Eject Magazine - AP Cost -5% (24.7)

Medium Quick Eject Magazine - AP Cost -5% (24.7)

Glow Sights - AP Cost -7.5% (24.05)

Short Scope (all variants) - AP Cost +30% (33.8)

Reflex Sight - AP Cost -15% (22.1)

Medium Scope (all variants) - AP Cost +40% (36.4)

Long Scope (all variants) - AP Cost +50% (39)

The numbers in parenthesis after each AP Cost modifier are the AP costs as determined by multiplying the base 26 AP by the percentage modifier. The mod in question indicates that the AP Cost modifiers are percentages; if so, then the values I calculated should be close to what you're getting. Probably the biggest issue I saw with your info is that you state that mods add a flat number; the thing is, multiplying out a percentage results in a flat number, especially since it appears that the game rounds to whole numbers rather than using decimals. So a percentage would still result in a whole number.

Also, you may want to double-check your numbers on the Long scope at the very least. I didn't cross-check everything (it would require a lot of scrolling, and I should really be getting some sleep for work right now), but you say that the Long Scope adds 14 to the AP cost. That means that the AP cost for a Short Hunting Rifle with a Long Scope would be 40 according to your numbers (26 + 14 = 40). However, my math is saying that you only need 39 AP to get a single shot. I'm not saying you're wrong, but if you are able to get a single shot only at 40 AP, then there may be something other than mods affecting the AP cost, because I don't know where that extra 1AP cost is coming from.

As an interesting note, the lowest AP cost you can get on a Hunting Rifle is a Light Frame Receiver, Short Light Barrel, Short Stock, Medium Quick Eject Mag, and a Reflex Sight. Assuming the AP cost modifiers are additive, you'd end up with an AP cost of only 10.4. Of course, the resulting weapon would be more suited to close range than sniping (Range is only about 130 without a Muzzle, and all muzzles reduce Range), but it's still a weapon based around accuracy and scoped shots rather than hip-fire. Damage is going to be lower, though, as the Light Frame Receiver also has a damage penalty. Still, I would be interested in finding out what AP cost you get for the same weapon. Muzzle choice is up to you, as no Muzzles for the Hunting Rifle affect AP costs.

Also, interesting note: the Reflex Sight (Dot) actually has 0.25x more zoom than the Reflex Sight (Circle). Every other stat is the same. Not really relevant to the discussion at hand, but I found it interesting that there was actually a difference between the two other than what the marker on the sight was.

Hey thanks for the information! Retested the long scope - it is sill at 40. I am thinking the base is not a flat 26. Or it may have something to do with the short barrel showing that -10%.

I am thinking the modifier percentages you posted apply to base stat, and are not multiplicative. They add a flat value based off the base weapon stat.

So lets take the WORST VATS Rifle you could ever make: Heavy Frame Receiver, Long Barrel, Large Mag, Full Stock, long scope and no muzzle enhancements.

Using my calculations I get an AP use of 26 + 7+5+6+5+14 for a final score of 63

Using the mods numbers, if they are multiplicative I would get 26(base)*1.25(heavy frame)*1.1(long barrel)*1.1(large mag)*1.2(full stock)*1.5(long scope) for a score of 70.1

And the real in game number is 61! So clearly, something is going a little wrong.

So we are both off. I think the percents you posted are right, but they add up and are not multiplied. I think the differences have something to do with the base stat not being 26. That the standard tier 1 mods are modifying the AP cost as well. Like that short barrel you posted as being -10% AP cost.

Edit: Using the mods you listed I got an AP cost of 12. I could not get a shot in at 11.

1. I was calculating additively. Total reduction was 60%, so we pay 40% of the base cost. Multiply 26 by 0.4, and you get 10.4.

2. According to the math, the cost per shot for the worst weapon is 55.9 AP. Total cost increase is 115%, so 26 times 2.15 equals 55.9.

I wonder if we're looking at this wrong. Maybe the final AP costs aren't factoring in the individual mods at all. Maybe they're only looking at the final Weight value, and are plugging that into some formula to get the final AP cost. Unfortunately, the only way I can think of to test this would be to get two different base weapons and mod them to have the same weights, then check their AP costs. Of course, even if they do match, I wouldn't call that definitive proof; wouldn't want to be a victim of confirmation bias, after all, so we'd need more data points, but it would be a step in the right direction.

Yeah, scopes help with long distance vats shots cause scopes alter the accuracy stat of the weapon, witch in turn increases vats accuracy. Though you can never tell if the char will shoot through the scope or from the hip in vats. Nor that when shooting using the scope in vats makes the shot more accurate compared to hip fire. Or maybe they are just alternate animation and the accuracy is the same either way.

I'v observed that for long shots in vats it's way better to ditch any scope (and get more ap as a consequence) and just get the Concentrated fire perk instead, adding 20% to accuracy for each consecutive shots in a vats round. Penetrator perk helps the accuracy indirectly cause often enough the most vulnerable part of the body is covered by other parts of the body (and obstacles).

Well for long shots I wood rather use a scope and free aim, ditching VATS altogether. Accuracy in VATS just drops to much at long range.

SWK, I am sure it is not related to total weight of the weapon. That would be a big difference from previous titles, and Bethesda usually does not do that. The numbers we are getting are close.

I still think the differences has to do with the AP adjustments on the base mods. For instance the mod says a short barrel drops AP by 10%. But the base AP for a hunting rifle with no mods is 26. Which means the base AP for the weapon is actually higher then 26.

It is probably 28. So a short barrel and long scope rifle would have a modifier of .4. Which gives a AP cost of 39.5. Rounding up to to 40.

A base rifle with no mods would have a modifier of -.1, giving a AP cost of 26.

Also, it is entirely possible the mod creator had a typo in his numbers!

Last point, each mod does add a flat amount. I was just missing the decimals. Since 26*(1 + .25 + .1) = 26*1 + 26 *.25 + 26*.1

Just being a math nitpicker!
I think we are close enough, rather then get bogged down over 1-2 AP. the real point is how certain mods have a really big impact on VATs

Absolutely...and the best weapon for this (IMO) is a .308 Combat Rifle with large clip (40 shots). you can rattle off a dozen very accurate shots while fully scoped (with scope of your choice) while any .50 Hunting Rifle weapon or Gauss weapon is still trying to fire 3 (with significant disruption of scope sighting).

Very difficult to beat The Deliverer in terms of a VATS short / medium range weapon. 10mm ammo is plentiful and cheap and you can accurately deliver well over a dozen shots in a single VATS session. I don't personally like the look of the weapon, but even out of VATS it can generate some impressive DPS (due to it's rate of fire potential).

Sudden thought: replace your barrel with a Long Light barrel. It's the only one without an AP cost modifier. Any receiver, standard sights, short stock, no muzzle. That should give you the base AP cost.

Yes, that would be 29. Using that as a base gives much closer numbers to what is actually observed.

For instance your super low ap rifles shows up as 11.6 or 12 rounded. Which is the minimum AP I needed to fire a shot.

The ultra heavy is still a little off 62.35 calculated vs 61 actual. But pretty darn close.

Probably some error in the calculation in the game engine. Where they round one mod but not another.

I love Righteous Authority, the more damage on crits stacks with the recever which does the same thing and the better critical perk making you 1 hit kill everything you crit and it fills the meter faster.