Hello!
Sorry for my english - I'm from Ukraine.
I was looking at an Ar-15 rifle from many American brands and decided to buy a Smith & Wesson. I bought an M&P 15TII. After the purchase, I started looking for information about the details of this model on the Internet and found this forum.
I was surprised when I didn't find my weapon on the official Smith & Wesson website. Has this model been discontinued? Why? Could it be related to quality or design?
If there are owners of M&P15T II here, please tell me what hidden features or defects of this model I should pay attention to.
Thank you.

Certain models are discontinued simply because they weren't selling particularly well anymore.

Rest assured, you have an excellent quality model there. The M&P15T II was a high-end model built to the highest specifications of any model in the M&P15 Series of Rifles.
Unfortunately, many felt that it was too expensive, so it didn't sell too well over time and was eventually discontinued.

Smith & Wesson hasn't had much success with higher end models because their exists an overwhelming sentiment that M&P15s are entry level AR-15 Pattern Rifles, so that's become their niche.
When it comes to their higher end models, the overwhelming sentiment expressed by people online is that for the amount of money they cost, you're better off buying from another brand like Colt, FN, or some luxury brand.

On the bright side, it means that the market has a number of excellent quality ARs available at lower prices because they've been devalued.

I myself just recently ordered an M&P15X — another of S&W's ill-fated high end AR Pattern Rifles — for less than half of what it originally was priced.

Here's an archived copy of the original product page on S&W's website:
M&P; 15 | Smith & Wesson

You made a fantastic choice of a top quality, American-Made tactical rifle, manufactured using state-of-the-art equipment and some of the finest materials available, unlike a certain faction of invaders armed with cheap rifles made out of stamped sheet metal. Don't let anyone convince you otherwise.

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Shooting Comfort is bilateral.

I have an M&P15T (not the II) and absolutely love it. As with all of my M&P rifles, I have never had a single issue with the 15T. You have purchased a fine rifle, my friend.

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Find a way or make one.

It appears you have acquired a high-quality railed AR-15 with lots of options for sights, optics and accessories. Put it to good use over there. Best to you and all in your country.

Hello!
Thanks for the information and wishes to me and my country!
Price is a really important factor. Because of the war, we now have an atypical pricing policy. ANY weapon is now very expensive. The difference between levels is very virtual. The price depends not so much on the quality or brand, but on the purchase price, logistics, customs and DEMAND.
My rifle was the last one in the store and had been reserved for another buyer for a long time. So I bought it at a good discount.
I am happy that you say that my choice is good.
Thank you!

Hi all.
I already shot from my new rifle. Very satisfied! Before that, I shot only from AK. AR is a new level of comfort!
I have a question. My rifle has a universal instruction for the M&P rifles (2019?). But my model is 2021.
But this instruction will not make information about certain details of my model. I would like to know how I can remove the forend (handguard). There are 2 screws below, one short with a round flat hat from above and some small drowned below. In what sequence to unscrew them?
I want to remove the forend (handguard). I saw that there was a very small difference between rail on the forend and rail on the upper. Because of this, MBUS mugpul had to be twisted in the maximum left position. Maybe the forend is screwed a little at an angle, and after removal will become in its place?
Maybe I was looking wrong. Is it possible somewhere to find the instructions of my model of a rifle, or the like?

Typically the instruction booklet provided is universal (i.e. covering all M&P15s in general rather than any specific model) and mainly covers safety as well as field-stripping instructions rather than details on how to completely disassemble the rifle.

Alas, I am unfamiliar with how to remove the handguard, but it ought to be in alignment with the toprail on the receiver so that front and rear sights line up properly.

I searched around and found the following thread:
M&P 15T quad-rail removal

Granted this is for the original M&P15T, but hopefully it will help.

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Shooting Comfort is bilateral.

The Tactical II has a few enhanced features compared to the Tactical. Newer grip, flat faced trigger, and 1 inch longer handguard. Other than that they're the same. I think the Tactical II only was sold for a year or two before the new XV Volunteer series was introduced.