Stock Player health is 100.
The percentages for Stopping Power, Sonic boom and Juggernaut are mostly irrelevant. A simple explanation:
Juggernaut was designed so that you survive take one more shot from any weapon.
Stopping Power was designed so that you would need to make one less hit with any weapon to score a kill.
Even without the literal cancelling-out, the two are perfectly balanced against each other.
Sonic Boom increases damage just enough for Hand Grenades to kill even at the very edge of the indicator range.
Hip Accuracy is simple enough. Draw a circle that touches all four crosshairs, and the bullet will land within that circle.
Steady Aim improves accuracy by shrinking the diameter and tightening the crosshairs to 65%.
I've yet to find the data for Steady Aim, so only an in-game test can get a result for now.
Credit to SSoG on the CharlieOscarDelta boards for doing his own test.
Doing my own test, using a PC screen resolution of 1680x1050.
Using the SAW's hip accuracy of 10, that way it is easier to calculate.
Two screenshots, with and without Steady Aim. A simple measurement, and the crosshairs have closed in at approximately 66% of their original distance.
Scaling the circles to any other weapon's crosshairs results in the same change in accuracy.
Using a mod for PC, I changed the hip spread of the SAW's 10 to 6.6, and it appeared a pixel too large.
Change to 6.5 and it is a perfect match to a 10 + Steady Aim.
End result: 65% hip accuracy exactly.
WHY THE G36c IS AWESOME
There are four weapons in the Assault and SMG classes that "idle" when sighted:
The AK47, the M4, the AK74u and the G36c
The first three all move from the center of the screen at the same speed and radius. The fourth is unique.
Not only does the G36c deviate far less, it moves slower AND stance improves its steadyness.
The hard numbers don't matter, saying they do 40 at 1.5 won't make a bit of sense, I'm just showing them to explain it:
The values involved are called ADSIdleAmount, ADSIdleSpeed and ADSIdle[Stance]Factor.
I'll just address the M4 since the three are the same.
M4 has a universal ADS Idle Speed of 1.5 and an Amount of 40, all attachments included (ACOG too).
G36c has 70% the Amount (28) and nearly half the speed (0.8) when sighted, standing.
Crouching, the G36c's idle Amount is cut in half (21) and the speed is almost a third (0.6) of the M4.
Prone, it'll barely move (11, 0.3).
The G36c is very steady when aiming down the sights compared to the other fully-automatic rifles.
Even moreso if crouched or prone.
Before anybody asks: No Sniper rifle or ACOG moves around less if crouched or prone. (oh hey, new discrepancy)
The G36c (+ attachments, ACOG included) is the only Primary Weapon that benefits from different Idle Stance Factors.
The pistols Idle at nearly the same rate as the G36c and have slightly improved steadyness when crouched or prone.