Try mam anti colic bottles. They are available in Target, baby bunting, national pharmacies and on www.babynest.com.au
. Their bottles have a one way valve that allows the air to enter to stop the vaccuum effect which in turn causes the baby to take huge gulps of air when the stop for a breath.
Most anti colic bottles have a hole in the side of the teat, all that does is airate the milk even further as the only source of air into the bottle. All mam products are entirely bpa free and they have a fantastic range, including bottles, dummies, toothbrushes etc...I love their products and advocate for them no worries.
Hope this helps !!