The following is copied from one of my comment replies for one of my YouTube PU sniper videos comment replies:
"Commercial Sellier & Bellot 180gr FMJ and 174gr HPBT Match ammo will follow the PU BDC (bullet drop compensator or range drum) to essentially MOA precision. Zeroed for either of these rounds, you dial in 7 on the PU BDC and you will be on at 700M for elevation, dial in 5 and you will be on at 500M, dial in 8 and you will be on at 800M, dial in 3 and you will be on at 300M, etc. That is the real beauty of it, you don't have to hand-load or do anything special and you can get these results. Of course, you may have to compensate slightly for atmospherics/altitude."
The following is an answer in response to a question from a YouTube viewer and fellow M91/30 (PEM) shooter regarding fine POI adjustment:
The elevation and windage adjustment knobs are mechanically the same, so a given amount of movement of either knob is going to give the same rate of reticle adjustment in either the vertical or horizontal plane. The windage scale has graduations in mils. One mil is 10cm at 100M (3.94 inches), 20cm at 200M, 30cm at 300M, etc. To get 1 inch of windage impact adjustment at 100M, just move the adjustment knob a 1/4 mil. So correspondingly a mil movement of the elevation adjustment knob should get you roughly the same type of vertical change in POI (point of impact). The trick is that there are no mil markings on the elevation adjustment knob, so you should make one (or two) for reference (see pic below). This will give you a means of making precision elevation adjustments rather than just guessing or using hold-over. What I do is scribe a thin line 1 mil distant on either side of the existing line that is on the fixed base of the turret (the line which you would turn the knob setting to line up with). Use calipers to measure a mil mark from the windage scale and then transcribe it to the elevation turret base. I figured this out on my own, but when I was looking through my PU scopes I found one that had been marked as such! I had probably seen the mark early in my collecting years but had no clue to what it was until almost 10 years later and had extensively and seriously shot these rifles.
An important operational item:
Always adjust out mechanical backlash error when moving your windage or elevation knobs, and do it in the same manner each time. This instruction is actually from one of the Russian/Soviet PU sniper manuals. For example if you are adjusting to 300M from 100M elevation setting, go past 300M to about 500M and then come back to 300M setting. So always rotate down to your setting, and you will be adjusting the backlash out the same way each time. This is critical for accuracy repeatability at different ranges for this type of scope with gear and friction adjustment turrets.
Safe shooting, John
