Conservation of Energy: 180gn VLD @ 2,950fps = 195gn EOL @ 2,834
Longer bullets get seated deeper, leaving:
a) Less space for powder
b) Less space for initial gas expansion (higher pressure spike even with less powder)
Essentially, loss of fps due to deeper seating. (maybe 2,750fps with similar pressures signs of 180 @ 2,950?)
Also, the heavier bullet acts as a larger plug in the barrel, which also increases pressures (both the spike and overall). Shouldn't that higher overall pressure result in a bigger push and relatively higher MV? Well I'm not sure about that.
7mm Mag in a long action or 7mm WSM/RSAUM in short action: Seating depth restricted by magazine length. (above applies)
7mm WSM/RSAUM in a long action
: Seating depth not restricted by mag length. Assuming same 8.5 (iirc) degree boat tail, overall internal volume should remain almost unchanged, just the COAL would get alot longer. This is why I'm so hard set on a 7WSM long action now
180gn VLD @ 2,950fps @ 1000 yards in 10mph wind: 256.6" (7.1 mils) down & 57.0" (1.6 mils) left/right.
195gn EOL @ 2,750fps @ 1000 yards in 10mph wind: 277.5" (7.7 mils) down & 50.2" (1.4 mils) left/right.
Theoretically, If you can call a 10mph wind +/- 20%, the 195gn EOL will get you +/- 1.4"
closer to the target.