Quote Originally Posted by MrPrena View Post
All Approx Number just to compare.
Rate of fire‎: ‎700?950 round/min cyclic (11.67 to 15 hz)
So it travels about 0.086s to 0.067s to a cycle dep on mass of bolt and velocity of ammo.



- 0.35" bolt carrier movement for bolt to unlock,
plus 1.750" case length
2.15" to eject a case;
to pick up a new round, 2.75"
for last round lock-back, 3.2".

5.56mm NATO M855
Vmuz=922 m/s (3,025 ft/s or 36,300 in/s)


l=14.5" barrel
v=(36,300 in/s)
14.5in / 36,300 in/s

approx 4.00x10^-4 sec for bullet to clear out the barrel
0.4 mili sec


0.086s to 0.067s to a cycle to pick up a new round, 2.75"
How about approx how long would it take 0.35"?

0.067s/2.75in = time bolt open/.35"

(0.067s/2.75in) (.35in)= time bolt open
8.53x10^-3s =
or 8.53mili second=

therefore bullet would leave the barrel even way before bolt rotates.
Oscil of metal from explosion is more significant than bolt travel time.
Wouldn't you only need to use the distance from the gas port to the end of the barrel in the calculation since the gas system isn't pressurized until the bullet passes that point? Not that it would alter the conclusion of your math, but if we are going to do math...let's be accurate.