I think you answered your own question. It's a combination BB and pellet rifle. I can add this information. It was made between 1969-86. It a pump rifle using the forearm as a pump. The name Benjamin Franklin was a marketing gimmick. Ben Franklin had nothing to do with it. Walter Benjamin started the company in 1899 and today it's owned by Crosman Corp.
it was made in 1975
This Benjamin Model is part of 3 rifles that are in a series. The 340 is a .175 BB rifle. The model 347 is a .177 Caliber Pellet rifle and the 342 is a .22 caliber pellet rifle. this line of air rifles was made between 1969 to 1986 (Model 340) and 1969 - 1992 (models 347 & 342)
Let me guess your Rifle is either a model 310, 312 or 317. It was made in 1965
T427432 was made in 1982.
The Benjamin model 310 is part of a series of rifles that included: 310 BB rifle 317 .177 pellet rifle 322 .22 pellet rifle All were made from 1940 to 1969 Today Crosman owns Benjamin and Sheridan air gun's, see the link below for a partial list of Dates of Manufacture. Scroll down on the list until you find the 310 section. It may help if you have the serial number.
I'm going to try to answer your question, but first I need to clarify something:You do mean Pellet gun not Pellet gum. You did not state the manufactures name so I think you mean "Benjamin 312 Pellet rifle."Now all you need to do is verify you meant "Benjamin 312 pellet rifle" and let me know the current condition of this rifle. Also state if it still holds air and is working condition.Then I can give you and estimate of value
Yes you can
Benjamin made a model 347 from 1969 to 1992 it was a pump handle that fired a single shot .177 pellet. As far as I know Benjamen never made a model 357 ( I may be wrong) but they have just come out with the Benjamin Rogue that fires a 357 caliber Pellet. This is PCP (PreCharged Pneumatic) class rifle. These are the most powerful class of air rifles today. The Rogue fires a 8 shot 357 caliber clip. The rifle cost around $1300. The 347 is designed for target and rodent control. The Rogue is designed for small to medium game hunting. The Rogue is not the largest caliber pellet rifle. Today the largest is the 50 caliber Dragon Claw air rifle by Sam Yang.
Benjamin (Owned by Crosman) has a new Benjamin Rogue it is a .357 caliber. At present it will be the largest Pellet rifle made with the Benjamin name. Yes it is a hunting rifle. The next largest Benjamin rifle is the Benjamin Marauder .25 caliber. Sam Yang make a 50 caliber and a 44 caliber hunting air rifle.
I am not familiar with this particular model (427) but I am familiar with Benjamin air rifle. If your problem is that there is on Scope rail to mount your scope then I know how to fix it. Crosman airguns owns Benjamin air guns. Crosman offers a special Benjamin barrel clamp that lets you mount a scope to it. See the link below
An air rifle could be made in that calibre. Benjamin made a model 242 and 247 in .177 and .22 calber from 1968-92 but not a model 243.
1980 see the link below. See the link for your date of manufacture