I'm a fan of interactivity, of choices that matter, of immersion and of games where not everything necessarily goes according to the plan. I developed a skill system for Fallout that is hopefully able to tie everything together. Before I'll give you an example, I want to thank several members for their ideas and impulses.

AwesomePossum for the advanced lock [censored].

Evlbastrd and Undecaf for their extended skill systems.

And AP, Gizmo, Undecaf, etc. for their insistence on RNG based systems.

I'll use a 1-5 SPECIAL system for this idea, so 5 PER means maximum perception for example. You can easily convert this though.

I segregated the skills into several levels. All explosive weapons fall in one of three categories for example: Lvl1, Lvl2 or Lvl3. The higher the level, the more powerful a weapon usually is.

Lvl1 summarizes basic explosives like frag grenades/mines, craftable mfc grenades, grenade throwers.

Lvl2 includes special explosives like pulse grenades/mines and incendiary grenades as well as bottlecap mines, grenade launchers and generally more powerful explosives.

Lvl3 is Fat Man, Missile Launcher, Plasma Grenade/Mine level.

Now the Explosives Skill has these 3 sublevels.

.Lvl1 (re. AGI 2 or PER 3):

You're familiar with basic explosives. Each point invested raises your efficiency with Lvl 1 Explosives by 1%. You may invest up to 50 Skill Points in Lvl 1.

.Lvl2 (req. AGI 3 or PER 4, 30 Points in Lvl 1)

Advanced explosives can be used with ease. Each Skill Point invested raises your efficiency with Lvl 2 Explosives by 1% as well as the effective range of all your Explosives by 0.5%. You may invest up to 50 Skill Points in Lvl 2.

.Lvl3 (req. AGI 4 or PER 5, 60 Points minimum in Explosives)

Explosions! Everywhere! All for you to blow up! Each Point invested raises your efficiency with Lvl3 explosives by 1% as well as damage done by all explosives by 0.5%. You may invest up to 50 Skill Points in Lvl 3.

As soon as the level is unlocked (as you meet the requirements), you may use the weapons of this category properly (you may use them before, but it won't be worth the time). Efficiency is a combination of converted chance of success and accuracy, modified by Luck. Base efficiency for all levels is 50%.

Just check out Cyberpunk 2020 rules for pointers.

Attribute+Skill+dice(d10) against task difficulty.

Agility 6 and lockpicking 4, task difficulty 15. Need to roll 5 or more to succeed. If att+skill equals as much or more than task difficulty, it simply succeeds without a need for a dieroll. Switch the numbers to better match Fallout.

There's a synthesis for you as simple as can be.

Thank you. That's really easy. Fallout would simply need to involve Luck somehow:

Skill+RNG vs Difficulty +- Luck difference. For example.
Additionally Luck should serve as an outside factor.