Can anyone tell what type of fragments (size, material) are used in SA-3 missiles?
What are examples of shot downs by SA-3. I read some about US aircraft shotdown in the Yugoslavia war?

How likely is it MH17 was shot down by a SA-3?

MH-17 was probably shot down by an SA-11, not an SA-3

Like it says in the SAM Sim manual for the SA-3.

5B15 warhead.
Weight: 52kg
Explosive weight: 33kg
Number of fragments: 3,570pcs
Fragment average weight: 5,4g

5B18 warhead.
Weight: 72kg
Explosive weight: 51kg
Number of fragments: 4,500pcs
Fragment average weight: 4,75g

Nobody knows what type of missile was used to shot down MH17. States like the VS tell us it was a BUK. I have not seen any proof of that. Untill then all options must be considered.

Looking for size of fragments. Round, square?

I would concentrate on fragment shape...
... butterfly shaped fragments are used only with the BUK.

Have you seen holes which could be made by butterfly shaped fragments?
Shape of fragments in SA-3?

SA-3 fragments must be similar to those....