Hi,
Are extension tubes legal in CT and what is the max rounds I can go with a pump?
Thanks!

Yes extension tubes are legal on pump shotguns. However, one is limited to 10 rounds max in that pump action shotgun tube magazine.

Sec. 53-202w. Large capacity magazines. Definitions. Sale, transfer or possession prohibited. Exceptions.

On a side note, there is further limitation on tube magazine capacity for post 9/13/94 manufactured semiautomatic shotguns in the old AWB, which still applies. In that specific case, if the post ban semi auto shotgun has a tube magazine in excess of 5 rounds, having any additional evil features (a folding or telescoping stock or a pistol grip that protrudes conspicuously beneath the action of the weapon) would make it an assault weapon.

Ive always been curious on how shell length vs tube length is applied to our laws.  

An 8rd tube holds like 12rds of mini shells.  Of course we would only load 10rds of minis, but would the mag be considered a LCM?

Yep, law doesn't address that. Just indicates if it has a capacity of more than 10 rounds its an LCM. Probably comes down to the law enforcement officer who discovers the firearm loaded with more than 10 rounds (outside of lever action or .22 cal tube magazines).

Some even get confused over the magazines used on shotguns like the Kel-Tech KSG. Two separate magazines that one has to manually switch between. Even there, each individual tube magazine is technically limited to 10 rounds. The wording of the stupid law is what it is.

To further confuse people, having a magazine over five rounds on a post ban semiautomatic shotgun is an issue if that semiautomatic shotgun also has either a pistol grip or folding/collapsing stock.

Remember, these are what Democrats consider "common sense" gun laws.

That's how I read it too.  

I tend to over think everything, and when I bought my 500, I got the standard 5rd mag because only 9 mini shells will fit in.

Most will say I'm nuts but I really don't trust people.  Same reason I will not carry my G19 with a 15rd mag, downloaded to 10.  Too much leeway for a "Oops, ya got 11rds in that there mag buddy..."

Eta.  I don't even trust they would make the right call with things worded in black and white.  
Like some say. "May beat the charge, but not the ride"  And that ride alone would probably take years to recover from.