Is there any way to globally affect projectile damage or speed and range,ect? Mianly thinking of a an arrow and bolt mod.

Projectile speed is a game setting. If you use a Bashed Patch it is very easy to change - you can just hit Tweak Settings and adjust the Projectile Speed multiplier - alternatively something like the Mod Organizer Configurator function, or even testing different settings ingame with the console.

Range is more difficult as it becomes dependant on your uGrids after a while. With all other settings at vanilla defaults, the setting fVisibleNavmeshMoveDist=12288.0000 in Skyrim.ini under [Actor] should allow projectiles to hit anything visible with a good enough aim.

Damage of projectiles requires a mod.

EDIT: Sorry, just read your title after the rest of the post and realized the context is wrong. Damage and speed should be easy enough to change dynamically - speed scripted, and an invisible perk to improve archery skill would be the easiest way to improve damage.

A few questions, can you do a script that looks for keywords and type of object rather than the name of an object? Say arrow or bolt, if not can you have it read all projectiles and change the numbers based on percentage values?

Let’s say I want all projectiles to be 50% faster and go 50% further, can this be done via a general script or would everything have to listed individually?

I’m pretty sure it has to be one by one but I thought I’d ask.

and dose not marksmen have a cap so damage only goes so far?