Recently I spent a weekend doing Russian language searches to find any pictures of Yak or La on hard stands being bore sighted from WW2 like we see for many allied aircraft. As far as I can tell, there are none. Instead I found references from interviews with VVS pilots about the guns being set at the factory. And what the VVS tactical doctrine was for air combat related to effective guns range.
The tactical doctrine was max shooting range for air to air combat, 200m. Past that your chances of getting enough rounds on a maneuvering target are very small. While you are expending a very small magazine of rounds for your guns. The PBP-1A reticle by the time of the La5Fn was able to be used for lead at 500m. But, just like the Germans, longer ranges described in tactical documents were for level flying bombers.
Both the UB 12.7 MG and the ShVAK\B-20 20mm have a similar ballistic to the AN\M2 50 cal. 200m or 218yds or 656ft, your rounds drop about 8 inches. The PBP1 two ring reticle reflects the 200m tactical doctrine with the inner ring is the average Mil diameter of the 109 and 190 wingspans at 200m.
Yak and IL2 props had a 200m zero mark on the back of the props. The PBP-1 had an elevation dial which the pilot could change the aimpoint for things like the NS-37 shooting at ground targets, bombs and rockets. But, otherwise all of the guns mounted for forward firing shot flat to 200m. I could find nothing that the factories set Yak and La guns other than shooting level and parallel forward. Even the P38 guns were set parallel but, harmonized to 2000ft. Same with the P39 hood guns, parallel and harmonized to 1000ft. German hood MG were also set parallel.
One interview of a Yak 7B pilot, he explained that the two 12.7 UB were used for air to air while the ShVAK 20mm was saved for ground strafing. He also talked about 200m and air combat. The twin 12.7 at close range were satisfactory for 109. The 20mm ballistics became different than the 12.7 past 200m.
I tested this with the Yak 9U and all guns set to 225. My first sortie was a 4 kill. I held fire in all cases until the range marker was 200.