The best place was the book "The Black Rifle", (vol 1), pg 352...TBR #1 has the A1, HBAR, and A2 dimensions...Not all the dimensions, but pretty close!
I know I've seen the M4 dimensions/layout drawing around somewhere, but I don't recall where...
ooops, was gonna suggest that or scan the page for you...
as for the M4, i seem to remember seeing a dim'ed drawing somewhere too, but can't recall where...
TBR #2 has drawings on p. 72 but no dims... p. 73 has some minimal specs:
std M16A2 5.56mm chamber, chrome lined, barrel also chromed
std M16A2 button-rifled barrel w/ 6 lands & grooves, 1 in 7 RH twist
std carbine barrel gas port location
gas port diam 0.0625"
the diam of the barrel from the front sight fwd is the same as on the M16A2, except for the groove for mounting the M203, which is the same as the M16A1
let me know if you want me to scan vol 2 p72 for the drawings.