I was looking at how guns work in the game and noticed few odd things:
There is a sight mod “iron sights” in the game.
Weapons by default do not come with any sights (sight bult in on the base stats somewhere. I don’t see sight dispersion or aim speed in weapon stats).
Adding iron sights does not improve guns in any way. (actually makes them worse due to mass and volume)
Weapons can have built in and default mods.
Multiple sights on same gun seems to cause no issues.
The rifle_scope and riv_scope have zero dispersion and aim speed. Should probably non zero.
The scopes have aim_speed attribute (lower=slower). But something odd is going on as the iron sights/no sight are faster than holo even though they have same speed. Even the “slower” optical scopes are equal to the holo sights in speed (though I only tested on AKM).
I think it would be best if weapons used iron sights. Currently adding iron sights to a weapon actually makes them worse due to extra weight and volume.
Suggestions:
Built in iron sights on almost all guns. +1 sight slot on them so a scope can still be fitted.
Some guns with default iron scope or optical scope (marksman rifles, hunting weapons and such).
Adjusted stats on guns so that with iron sights they are as they currently are but without any sights they would be very inaccurate.
Balancing on how sight speed works so that slower sights are actually slower.
Should probably check to make sure multiple sights on same gun works always. Should probably use the sight that has lowest dispersion always or the sight that was added last.
To my knowledge, pretty much all guns start with default iron sights (base dispersion), so the iron sight gun mod is just in case you have a gun with higher than normal base sight dispersion (maybe makeshift?).
Some sgihts not only add weight, but volume as well. Higher volume makes aiming slower, but only after certain treshold. For pistol i think its arround 1,5 l. volume. So, if you have pistol that is 0,75l. that has basic iron sights built in with 6 aim speed, and you add holo sight you have 1.0l. pistol with 6 aim speed, but lower shot dispersion. If you add the same holo sight on 1,5l pistol, you will lower your aim speed, because incrased volume starts to get in your way. So on this 1,5l. pistol you might consider red dot sight, it has worse dispersion, but adds no volume to the gun.
Overall, i agree that every gun which has built-in iron sight should has it listed in gun mods, and have more slots for additional sights.
There is one more case that is strange. There is upper limit of volume for scaling aim speed, i think its arround 2,5 or 2,75l, here your rifle will be permament 46 real aim speed (very low, pistols can get up to ~290 on high stats and skills). Adding underbarrel laser sight to your Barrett m107 does nothing, because it is too big and already has lowest, capped aim speed of 46. Adding scope to your Barrett m107 does not increase your aim time because its already capped on lowest possible aim speed as well. It feels wrong that you can only modify aim speed of guns between 1,5 and 2,75 litres volume. Ok, adding laser sights or scopes to small firearms changes it a little, but when you get to a point where volume matters, the biggest changes come between said volume range, and usually youre stuck with arround highest possible aim speed for tiny weapons, and slowwest possible aim speed for most rifles, no matter the sights, scopes or mods youre using. Maybe for example adding laser sight could rise lower aim cap from 46 to 54, so adding it to big gun changes anything.
And adding scope with worse aim speed than standard iron sights can further decrase aim speed cap, 46 to 30, unless parried with second, faster sight.
If you are talking about the offset iron sights it is so if you have a weapon mod that blocks iron sights (main one I can think of is the homemade suppressor) it will allow you to use slightly worse but still usable iron sights.