TMM,
You can use 2 3/4" shells of the proper gauge in 3" chambers with no problems (but NOT vice versa)- just make sure the bores are clear, and don't shoot steel shot in barrels not made for it. In fact, it's likely to be a whole lot easier on the shoulder shooting the 2.75" stuff than the 3" magnum loads, and it's best to get started or to have fun with lighter loads anyway.
It won't hurt the forcing cone at all, most of my shotguns are chambered for 3" shells and I very rarely ever shoot 3" in them. I don't usually need to throw that much lead, I don't shoot steel at all and I don't like getting beaten up by recoil any more than anyone else.
The Uplander looks like a nice gun, hope y'all have a good time with it.
Stay safe,
lpl/nc
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http://hunting.about.com/od/shotgun/l/aastshotgunfaqb.htm
20 Most-Asked Shotgun Questions - Page Two
By Layne Simpson, Field Editor, Shooting Times.
Page Two
No. 11
Do 2 3/4-Inch Shells Pattern More Uniformly In A 2 3/4-Inch Chamber Than In A Three-Inch Chamber?
My father is of the opinion that the firing of 12-gauge 2 3/4-inch shells in a gun with a 2 3/4-inch chamber produces better patterns than when they are fired in three-inch chambers. If this is true, the performance of short shells must be awful in guns with 3 1/2-inch chambers. Do you agree?
Through the years I have pattern-tested enough short shells in long chambers to become convinced that the information you have received is more speculation than fact. Only a few weeks ago I fired several 12-gauge 2 1/2-inch and 2 3/4-inch loads in an autoloader with a three-inch chamber, and the patterns they produced were just as uniform as those shot with three-inch shells. I then took the experiment another step by firing those three shell lengths in another shotgun with a 3 1/2-inch chamber and could tell no difference in pattern quality than when 3 1/2-inch shells were used. I have also experienced the same results with other gauges. Sometime back I bought a 1930s-vintage 20-gauge double with 2 1/2-inch chambers and pattern tested it with shells of that length made by the British firm of GameBore. I then had the chambers of the gun lengthened to 2 3/4 inches, and pattern quality with those same shells remained the same when fired in the longer chambers. The 2 1/2-inch shells also produced beautiful patterns when fired in a 20-gauge gun with three-inch chambers.
No. 12
If A Three-inch Shell Fits In My Gun’s 2 3/4-Inch Chamber, Can I Fire It Safely With The Longer Shells?
The barrel of my 12-gauge shotgun is marked for 2 3/4-inch shells only, yet a three-inch shell will easily slip into its chamber. Does this mean it is safe to shoot three-inch shells in my gun?
Absolutely not. The linear dimension used to identify a particular shotshell refers to the length of its fired case and not that of the loaded round. Actual length will vary slightly among various brands of shells, but those designated as 2 3/4 inches usually measure around 2 5/16 inches before firing and 2 5/8 to
2 11/16 inches after firing. Three-inch shells usually measure from 2 1/2 to 2 5/8 inches before firing and lengthen to just under three inches when fired. Since the 2 3/4-inch chamber of a shotgun will usually measure at least that long, and sometimes slightly longer, you can see how an unfired three-inch shell will drop right into it. Firing shells of excessive length for the chamber can generate dangerously high pressures for the following reason: The inside diameter of a shotgun barrel rapidly becomes smaller just forward of the front end of the chamber in an area called the forcing cone. When a three-inch shell is fired in a 2 3/4-inch chamber, its crimp section opens into the forcing cone and in doing so effectively reduces bore diameter at that point. If the shot charge and wad column are required to squeeze through this partial obstruction, chamber pressure can increase.
