He didn't mean whole in the sense of very little of the bullet breaking off like would be the case from test firing a bullet in a trap. He made clear by the weights that they were ALL just fragments.
You can't possibly know what he meant - his words, his witness statement, he being at peril of being prosecuted if he included details which he knew not to be true, or to be false...
Now, choose carefully what you say next, because if it be your case that Fletcher did not mean that both bullets were 'WHOLE', then he has clearly made a false witness statement, a fact he knew not to be true, so what's your explanation...