The Army's Expert badge was, when I did basic in 87, issued for M16 by hitting 59+ of 60 man sized pop targets at a mixture of ranges from 100 to 1500m, when given 60 rounds of ammo, on any one of 5 qualification attempts. Sharpshooter was 55+, IIRC, and Marksman was 45+ or so. I requalified expert on 1st attempt; 59 targets dropped with 3 rounds remaining. (I had 3 shots that hit two targets each. Poor course design, IMO.)
When I qualified as a cadet, the year before, it was a total aggregate score of 380+ (of 400) on 20 rounds each at 100m & 250m standard NRA paper targets. 3 cadets made expert out of a company of 115 shooting, and 20+ made the 360 required for sharpshooter. Region waivered the unit to wear the army badges, issued by the AK Army National Guard. 12 failed the 320 required for marksman; that's an average of hitting the 8 ring or better. It was actually harder to get the NRA badges than the military ones.
Current army qualification badges for weapons are essentially based upon level 0 skill and dex... so for CT, I'd say Sum of Dex adjustment and level of 0 = Marksman, +1 = sharpshooter, +2 Expert, and +4 = sniper.
Most qual badges are not skill based... they're accomplishment badges.
Airborne wings are not granted for being able to parachute. They're granted for having completed the airborne school, or for having completed a combat jump in an active theater. Senior is 30 jumps, of those, 15 with full TO&E combat gear, 2 night jumps, and having lead others in jumps. Master is 65, 25 with full TO&E combat gear.
In CT/MT terms, if one is army or marine and has parachute skill, he should have basic wings. For senior, In basic CG, roll terms since getting the skill or less to have earned senior, and master would be made the senior roll, and, adding another die to it, still made it. For Advanced CG, each combat tour gets 1d6 qualification points towards award, as does gaining a level in skill; at 20 and 40 one gets senior and master.
The CIB is a "I was in an infantry unit in actual combat and survived" with a once per war per soldier limit. Higher awards are for additional wars in which it was earned.
In CT/MT advanced CGen terms, character is in infantry, and has raid, counter insurgency, or police action.
The other element, tho, is that typical restrictions result in many senior enlisted not being able to wear all of their badges. Even some cadets have run into the limits.
http://en.wikipedia.org/wiki/Parachutist_Badge_(United_States)
http://en.wikipedia.org/wiki/Combat_Infantryman_Badge