Fliptop bottles not carbonating

[BoomerHarley]

So I bought a bunch of fliptop (grolsch style) bottles from Morebeer. I have used them on three batches of sour ales, all which took months to brew and age. I also used regular bottles with caps for each batch, bottling fromt he same bucket in the same manner and storing them side by side. In every single instance the fliptop bottles remained flat while the bottles with caps were well carbonated.

I plan on yelling at Morebeer and demanding my money back. Needless to say I am a little angry considering the time and effort i put in to these beers. But I have to wonder, why the hell would this happen?

My guess is that the seals on these bottles are made of a harder plastic than typical grolsch bottles and it is not sealing correctly. I have used them successfully with a beergun and they hold pressure but I wonder if they need pressure to maintain a seal.

Thoughts?

 

[Tiber_Brew]

Are the gaskets a similar shape as the Grolsch ones, just different material? If so, you can buy spare gaskets like these for fairly cheap. Especially if you can get Morebeer to pay for them