if you fire Death Head at 0.1 deg. it does not always split.

For me it happend every time, if I first set angle at 0 and then increase it to 0.1

The weapon may not always be getting a apex to split from.

At 0.1 it should always split. That's basically millimetres away from the gun.

Thats 0.1 power not 0.1 degrees.

Today ive tested it again. It does not split when shoot at 0.1 degrees with shooting power from 0 to 1000

There is hardly ever a reason to shoot a DH at 0.1 power. I meant what I said. The apex is millimetres away if a MIRV or a DH is shot with elevation of 0.1 degrees, regardless of power.