"alloy jump frame with 130mm bombers"
I'm guessing here but is the frame on the small side and the fork a little on the tall side for it? Are you also running a short stem?
That combination could be chucking all your weight a lot more onto the rear (unsuspended) wheel more than a more balanced bike?
You could try trying to make the bike a little more balanced in terms of bringing your weight forward but I guess that would defeat the point of the bike
How bigger tyres are you running? Something like a 2.5" High Roller/Minion or 2.25" Advantage make you have to stretch a standard inner tube to fit the tyre loads, making the tube thickness a lot thinner. Not full on DH tubes, but something a little thicker, like the mid weight Maxxis Freeride tubes (some on CRC), helped out me with running 2.25" Advantages as they seem to inflate to the tyre size
Avoid continental 2.5" or bontrager 2.35" ones though, far worse than something like a 2.2" specialized tube. Those 2.1" Raliegh ones off of merlin are way thicker than any of them though (though not as thick as a maxxis freeride one)
Else as above(Apart from all the 'light' riders saying 40psiisneverneededbyanyoneever..), tubeless, dual ply, DH tubes