I have a 20 gauge Savage/Springfield model 511.
The 511 is an economy grade gun that is actually cheaper than the model 311.(Hard to believe I know). The forend is held in place by a screw, not the traditional spring latch of the 311.
The 511 can be broken down but it is a more complicated process than the 311.
Under the forend is the cocking mechanism. It is a round pin surrounded by a coil spring. One end of the pin engages the front part of the action while the other end engages a lug on the underside of the barrels.
To separate the barrels from the action you have to tap the end of the pin sideways to remove it from the barrel lug. Then the barrels will separate from the action. The pin is under pressure from the coil spring so you have to watch for flying coil spring.
I bought my 511 in "as new condition" on a consignment rack for $145.00 in 1983. Despite it's super economy grade status it has never failed to go bang and has brought home many a squirrel and rabbit.
Mine has 28 inch barrels and is choked improved & modified via the brass choke gauge. I don't think it has any choke markings on it.
Hope this helps,