Here are
several manuals available online from Browning. I don't know which one, if any, is correct for your model since you have the safety in a different place. My guess is none of the manuals listed and you will have to request one for your model, once you know which one you have, via the online order form.
You may wish to call Browning to verify just what model you have. They will probably need the serial number and be sure to tell them about the location of the safety.
The ammo you are having trouble cycling, 2-3/4" #7-1/2 shot, may be too light for the manner in which your friction ring is set up - but it is still possible that the gun is just too dirty (deleted)
It sounds like you have a early A5 with the safety like the one on an early Remington Model 11 as seen in
this article.
While 2-3/4" shells may work in your gun, it may only be chambered for 2-1/2" or 2-9/16" shells.
Read this and ask the Browning people what you have. Just because it fires the 2-3/4 does not mean you should be using them in it.
Regardless of what your gun is chambered for, and it may be even less than 2-9/16, I believe the friction ring set up is the same for light and heavy loads. There are also a host of videos on youtube.