Eldritch Archer Spell Combat Spellstrike Math ?

[Sarrah]

Lets say we have a character that has a base ranged attack modifier of +10. Rapid Shot = +8/+8.

Is Rapid Shot + Ranged Spell Combat = +6/+6//+8?

Is Rapid Shot + Ranged Spellstrike = +8/+8//+8?

Is Rapid Shot + Ranged Spell Combat + Ranged Spell Strike = +6/+6//+8//+6?

[Shisumo]

The penalties from both Rapid Shot and spell combat apply to all your attacks in a given round. So any series of attacks that involve both Rapid Shot and spell combat will be at +6 across the board.

You can't get more than one attack on a turn where you use ranged spellstrike without also using spell combat, so there's no way to only use Rapid Shot and ranged spellstrike just by themselves.

[Casual Viking]

Spell Combat: As a full-round action, he can make all of his attacks with his melee weapon at a –2 penalty and can also cast any spell from the magus spell list with a casting time of 1 standard action (any attack roll made as part of this spell also takes this penalty).

So, that's -2 for Spell Combat, -2 for Rapid Shot; +6/+6/+6. Note that attacks that aren't part of the full-round action, such as from opportunity shot or snapshot, do not take the penalty.

[Secret Wizard]

I like how OP never even put that down as an option XD

[My Self]

By 2nd level, you could have:

3 attacks at full BAB
1 base
1 from spell combat - > ranged spellstrike
1 from rapid shot

You'll be taking the following net penalty to hit, before stat and weapon modifiers:
-3 total

+1 from BAB
-2 from spell combat
-2 from rapid shot

So by 9th level, you could be rocking:

6 attacks total

5 attacks at full BAB
1 base
1 from haste
1 from spell combat -> ranged spellstrike
1 from rapid shot
1 from manyshot

1 attack at BAB -5
1 from BAB

You'll be taking the following net penalty to hit, before stat and weapon modifiers:
+3 for primary shots, -2 for secondary shot

+6 from BAB
+1 from haste
-2 from spell combat
-2 from rapid shot