A survey in the ETO during ww2 was taken of the combat film from 701 sorties. Of this 186 aircraft were shot down. Of the 701 pilots, 39% shot down the 186 aircraft. The common theme.
The 39% were shooting inside of their maximum effective combat range.
Wing guns were not harmonized past 1100ft or 366yds as a general practice. Hood and nose guns, 666yds was considered maximum effective gunnery range along with that being the maximum effective range for the AN\M2. 1200ft or 400yds was considered maximum effective combat range by the time the
1944 AAF Manual "Fighter Gunnery 1st Edition" was distributed by the Army Air Forces Training Command. This is not a copy writed manual. Wonder why the Trainers don't issue this, or it's view only somewhere on the AH WEB site? I had to buy mine.
The manual was created by the instructors at Army Air Forces Instructors School, Matagorda Peninsula, Foster Field, Texas. They used the 701 survey results as part of their class on range estimation and it's importance.
Since we only get sent to the tower for another ride in our game if we make a mistake. Any convergence is a good convergence if that's the one you spend all of your time shooting with. A 100mph ring or 101-105Mil gunsight ring is best at combat distances of 400 and under with a convergence in the 300's for deflection shooting at the speeds we fly in the MA.
At the default head position in our fighters, the general dimensions of the reflector glass is about right to act as a 100mph ring for natural deflection shooting with only a dot. The red range icons take the place of needing a ring to tell a 30ft wingspan fighter at 2000ft, 1800ft, 1750ft, 1200ft or 750ft. Just don't shoot until it's wingspan or fuselage is mostly in the glass. And deflection shooting, if you don't have a ring, you naturally learn to use multiples of the wingspan or hold deflection lead by placing the edge of the glass on the con. Or years of trial and error with your favorite fighters sight picture. For the alt monkey dive, HO, and run P51D players. Shoot sooner and farther in front of your target as you dive down at him.
100mph Ring in gunsights came from the distance a plane at 1000ft travels 90 degrees to you with the AAF, at 100mph across half of the 100Mil ring diameter as you look through it or, 50Mil. By the time you reach a 300mph late war fighter, the lead for 300mph is an additional 2 50Mil, one for each additional 100mph. That's why combat range in ww2 was 1200ft and under. Longer shots were most of the time strafing where you had pull up concerns and debris strike concerns. Because you were shooting at material and soldiers, the wide dispersion past your standard convergence gave a higher probability of hitting things in the moments you had on target. 50cal API is a very destructive round to things like that. It doesn't take many. Unlike in our game where you have to focus rounds on a ground object for a pre determined amount of time to destroy it.
100mph = 101Mil main ring.
65 mph = 70Mil main ring.
This illustration best shows the relationship of your 100Mil ring to the relative travel angle of the con at around 300mph. This illustration is for a 70Mil ring with a con at 65mph. Where the 30 degree 109 is sitting, is 100Mil ring edge. Speed and time equal Mil to the calculations that created this chart.