He was a marksman at Greshams. He went out bunny shooting on the eve of the murders. He asked the Eatons about acquiring a firearm to go pigeon shooting on the fields behind Bourtree. As usual you are not thinking it through!
You are not thinking it through. By his own admission and others who knew him it at the time he didn't have a massive interest in firearms, but was proficient. Blood sport wasn't a passion of his.
He by his own admission
once got a marksman score at greshams. He himself has referenced " he can't hit a barn door"
Rabbits are invasive to farm crops, this is part and parcel of farming.