Both sides have valid points but lets be honest and reasonable. Who cares what minor adjustments are made to the many well used field grade guns. They made tens of thousands of them and if they are not in high condition or rare for some reason the supply will not run out in the next fifty years. A graded or rare gun in pristine or even high condition is another thing I agree. But reaming out .010 choke is not a mortal sin.
Some alterations are much more disagreeable than others. Here is my short list. Do these and may you spend an eternity at your mother in laws house, with no chance for escape, or H--- which ever is worse in your case.
1 Never port a double gun.
2 Do not install screw in choke tubes.
3 Never install an adjustable comb.
4 Never install an adjustable butt plate recoil pad.
5 Never remove or polish case color to make the gun a coin finished gun. 10% case color beats a mirror like gleam everyday. 6 Never cut chamber to those 3 1/2" Roman Candles in a 12 bore. Best to say away from 3"chambers as well.
7 Never engrave the shield with your initials if no previous owner did in 75 to 100 years. What, you are the first important owner this gun has ever had?
8 Never put a vent rib on a gun that does not have one on it. They look like crap.
9 Deacals may go on a car bumper, but never on a gun barrel or stock.
10 Do not have your name, initials, SS# or drivers license #engraved on any part of a gun.
I am sure you may have a few more. This is my major list of things that make me want to hammer a few fingers of gun owners.
