Better with a 12-gauge

I'm finding indoor shooting incredibly frustrating at the moment. When shooting practise cards, I can do really well: I've got a really good 98 last week. But when it comes to match cards, I just shoot completely rubbishly. The last three cards have been 89, 90, 87 (today). It's infuriating: I don't know what's wrong with me. Sorry for lack of journal today: I'm still working on it.