Try Midwest Gun Works
Send it to a Browning authorized repair center.
0 100-1000 USD and up depending on specifics
Mid 80's
Need date of mfg, serial number, and condition to price most any firearm.
I bought a Citori Plus, in a combo set, which included a 34" trap barrel and the O/U barrel, plus the case. I bought it new about 8 years ago for $2400. I would think you could get around $1500 for the plus model, non combo set, if it is in very good condition, less if it has been "used".
50-350 USD or so
13 yrs old. 800-1000 USD
You must call Browning for the answer.
I don't think there is an invector plus model. Invector Plus is the choke system Browning uses on newer shotguns.
You will have to call Browning to find out.
To calculate the area of an HVAC duct reducer, you measure using a trapezoid area formula, which would be 1/2 times the base plus the top, times the height.
Used gun values are driven by several factors. Condition, does it come with choke tubes, papers, original box, and point of sale are a few. Go to one of the used gun sites like gunbroker.com and compare.