Sabot range for modern autocannons

[dmnt]

I've now done some early analyses and come up with the following findings:

• Bofors L70 40mm has two generations of APFSDS ammunition with differing penetration values.
• Bofors L70 40mm APFSDS ammunition has exceptionally low drag (the penetrator may fly up to 40 km!)
• Penetration data (Bofors 40mm L/70) for differing distances and ammunition generations is hard to find from reliable sources. Unnamed sources agreeing may have a common ancestor.
• Bushmaster 30mm APFSDS has a low drag, but not as low as Bofors L70 40mm's.
• Rheinmetall 120mm APFSDS data on OOB is in accord with the calculations
• This model works well only when the projectile has at least Mach 1.1 speed. All bets are off after that point.

The good news here is that because the model predictions for tank sabot ammunition is well within margin of error in the source data: for Rheinmetall 120mm L/55 DM53 the sabot penetration @3km is modeled at 676 mm vs. 660 mm in the MBT_APCalc.exe. Closer distances are even better aligned, for example @1km 854mm vs. 860mm. This gives me confidence that the model isn't grossly off.

Further checks I made were to check the NSV 12.7mm values given by MIL-STD-662F p. 20. The predicted velocity and observed velocity are within 2.25% of each other. I.e. the small caliber should not affect.

I'll continue with Russian autocannons to see if they follow the suit and the OOB and the model agree there. Then we can say that it is the low drag of these and only these projectiles that require tweaking.