Some really interesting info came out of a chat I was having with a sales lady at Plasdene yesterday. I noticed on their website they have a large range of different 330ml bottles available, and while browsing them all, I noticed that the heaviest 330ml bottle was actually rated for the lowest volumes of co2.
To see what I'm talking about, have a look
at this page. Note the model # 278, 246 and 331 amber bottles. Weighing 205, 205 & 248 grams respectively, and all rated for 4 "gas volumes" (which she confirmed is the same as our 'volumes of co2'). But then have a look at the mnodel # 310 bottle...again 330ml, but weighing a hefty 285 grams. But it's only rated for 3 gas volumes. which would be pushing it for any users of carb drops out there, or those priming their bottles high for a weizen style of beer.
When I asked why, she launched into a way-too-detailed description as to how bottles are made...stuff about blowing vs pressing, mould-blows vs semi hand made and the like. She lost me for a while...but basically it came down to the way the bottle is made, and its shape. And it's true, their heaviest 330ml bottle cannot handle anywhere near as much pressure as their most light-weight glass stubby.
Plasdene mostly wholesale, however they will sell to the public with a minimum order...works out to roughly 600 x 330ml bottles. Any interest from fellow Melbourne bottlers out there for a bottle bulk buy? Price would be roughly $20 per 100 stubbies.