Ragnar gives a unit D3 bonus attacks, INSTEAD of the normal +1.
The standard +1 attack is not claimed because a dice is rolled instead of it. So a unit with rag will get a bonus of a min +1 to a max of +3 attacks and thats it. This means an averange of +2 attacks per round. Thats what blood claws do in the first place.
What i am unsure of, is if the D3 deducts the initial +1 bonus attack of the claws. Since ragnar and his unit roll a D3 instead of the normal charge bonus, this leaves the claws only with the second bonus attack, plus the D3 result. Sum it up to an average of +3 attacks (2 min, 4 max).
But even if this isnt the case, i would save those 240 points to add a second claw squad. A common 7 man squad of claws with ragnar, will get:
1 normal attack
+D3 ===> av of +2 by bravado
+2 from bloodclaws berserk
total of 5 attacks, x7 units =35, +7 attacks gained by ragnar (berserk bonus doesnt aply to him)= 42 attacks
a second unit of claws instead of rag would give you 3 attacks per charge
for 14 models (2 sq of 7) this gives = 42 attacks
There are other bonuses as well, but the points difference isnt worth it....my opinion though