Verm, Juzz, there should be no significant dispersion on the guns. On the 38's case, if 1 round hits, all 4 should be hitting since the guns are packed in an area no bigger than a soccer ball (or basketball). At close range, d300 or less that would also include the 20mm.
Posted by Widewing:
"All of the P-38's guns are fired via individual solenoids. All of the Brownings will have virtually identical "lock time". "Lock time" defines the time between the release of the hammer and the firing pin striking the primer. All of the solenoids should have nearly identical field rise times, meaning that all should pull in at the same time, give or take a few milliseconds. So, for all practical purposes, all five weapons will discharge at the same time. Thus, the first five rounds will be heading towards the target in a tight group, equal to the actual gun placement or pattern. When the arrive at the enemy aircraft, they WILL STILL BE IN THE SAME GROUPING (with the exception of the 20mm round, see below). Hence, they will strike the enemy aircraft with the same pattern. There will be no significant dispersion whatsoever, other than ballistic differences between the Brownings and Hispano. As the weapons cycle, all four browings will discharge simultaniously, with the slower cyling Hispano lagging behind. This next series of .50 cal rounds will follow about 80 milliseconds after the first group, and will arrive in a group as well. Obviously, the 20mm round will arrive later. Assuming the enemy aircraft is moving at 300mph across the shooter's path. Then, the aircraft has moved about 35 ft since the first group of rounds struck (this assumes that no attempt was made to pull lead). In all likelihood, this second group will miss altogether. Remember, machineguns fire at a specific rate, and if all are triggered at the same time, this rate can now be identified as groups seperated by the cycle time of the weapons. Think of the Browning's cycle time as a continuous sine wave. with the hispano being represented by a corresponding wave of a slightly different frequency. Therefore, for a long burst you will have two distinct patterns developing with one out of phase to the other. With multiple guns, you simply don't get the "stiching" effect seen with a single weapon or that protrayed by Hollywood. You will get groups of hits seperated by the time/distance equation.
Think of the P-38's weapons as a garden hose.
The concentration will make you very wet. Bring one gun to bear, and all are on target. This provides a downside as well. Miss with one and it's likely that you have missed with all. Wing mounted guns increase the chances of a hit, but nose mounted ordnance tends towards a greater mutiple of hits (except when at the convergence point), therefore more damaging hits should your aim be true.
There should not be any significant dispersion of .50 cal rounds from the P-38, right out to maximum range. Deflection shots will move the 20mm round(s) out of the general pattern due to reduced velocity and slower cyclic rate."
"One last factor. Boresighting. Every fighter gets boresighted on a regular basis. Pilots have their favorite setups. The P-38 can have its guns set to converge at a theoretical point, or they can be sighted parallel, with dispersion being minimal on the sighting range. Either way, dispersal is not significant at the ranges typically encountered in WWII ACM."
"Note that I have not disputed that dispersion is greater at extreme range. However, we should be confining our discussion to "effective range", distances under 1,000 ft. Moreover, in a snap-shot situation, dispersion is not an issue as only the first group of rounds is in question. Unless, the pilot trys to pull lead and let the enemy aircraft fly through the stream. In such cases, maneuvering, more than any other factor, will create a cone of dispersal, wherein the weapon, ammuntion or mounting are not of great significance. The greatest disperser of fire is the motion of the aircraft, which is never anywhere near as precise as the accuracy of the weapons themselves"
"Normal dispersion can be assumed to be related to normal accuracy. Since a well maintained Browning M2 should group its round at something less than 2 inches at 100 yards, I imagine that normal dispersion cone per gun at 1,000 yards should be in the area of 24 inches. If the quality of the ammunition is consistant, all the rounds fired simultaneously should arrive within a very few milleseconds of each other. You should realize that virtually all of the dispersion cones will overlap at longer ranges.
Since all the firing solenoids are switched at the same time, and because each solenoid will pull faster or slower than any other (we're probably talking about microseconds), it is not possible to accurately guess what the firing sequence is. Nonetheless, I feel safe saying that for all practical purposes, they fire at the same time."
http://www.hitechcreations.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=9&t=002464 =P
