[colinicky]

Used mine yesterday out of Eastbourne, dive lasted 2 minutes ! Hit water immediate thought "think I nead to get back on boat NOW ! by the time I thought that water had passed the pinched O ring & filled my right sleeve to the shoulder This was using the outer seal but I put a piece of surgical rubber under the inner seal to allow migration of air so it might pay to use something a lot thinner under the inner in case of this .

I had checked & double checked the fit ,everything was snug to each other but it does happen ( about 50% of the time )Problem is made harder for me as I have a rebreather with front lungs which prevents a lot of movement for checking .I have used the other type of dryglove with the same sort of results but as you say at 30 metres it does squeeze alot .