as part of my ongoing testing with these bullets, i've started to drill open the hollow point to see how it makes them act.haven't actually put any through the air, but i have drilled several out. i've only completed about 5 of the 300's and around 12 of the 250's. in every 300, i've pretty much had to drill all the way in. there doesn't really seem to be an air pocket. with every 250, once i've broken through the jacket tip, the bit just goes in not quite a half inch and smacks against the core. this has happened on every one i've done so far.certainly not like grinding them in half but it has been very consistent so far with the few i've done.