Do I need longer reat shocks w/ Air bags?

I have Firestone bags and noticed a violent clunk when going over a particular cattle gate. Could it be the shocks bottoming out? Do other air bag users install a longer shock, and if so, what are my options?

 

Sorry, title should read rear shocks.

 

How much air in the bags? You removed the stops when you put the bags in - be sure they have enough pressure to serve as the travel stop. Mine will thunk too if I run less than 20 lbs. Takes bit of tuning to get happy spring rate. My bed usually has a full tool box, high lift, stall mat floor protection, and so on.... And that's "empty".

 

I did cut the stops when I installed the bags.

It thudded when I was at about 10 lbs with no load in the bed.

Currently have about 750 lbs of sh!t back there and pumped them to 20 lbs.