The Ultimak AK Scout Rail for the AK-47/74 is and has been the top option as the best first upgrade available. The Ultimak AK Scout Rail provides you with the option to add an optic and light which are really the only things needed to run an AK efficiently. The Ultimak AK Scout Rail weighs a mere one ounce more than the stock AK gas tube! So it is lightweight while adding picatinny rail which allows you to run an optic that will co-witness. Some people are into the co-witness craze and some are not. I could go either way, but ultimately it is personal preference. The thing I like is if you run an optic, like a Aimpoint T-1 or a knock off of it, your sight picture does not change if your optic stops working and you have to go back to iron sights. There is an upside there that I like, although you could easily use a QD mount with your optic and just throw that optic off it is stops working. Again, that is personal preference, but the Ultimak AK Scout Rail gives you options.
As far as mounting a light on the Ultimak AK Scout Rail the best option I have found is the Haley Strategic Thorntail light mount. I have run a Surfire G2X on my AK-74's for years with great success. Using the HSP Thorntail picatinny version is low profile, so adding it in front of an optic does not interfere with sight picture. I have found this marriage of the Ultimak AK Scout Rail and the HSP Thorntail with an Aimpoint T-1 red dot to be my preferred setup at this time. Now while I have gotten off track some on talking specifically about the Ultimak AK Scout Rail, let me not overshadow it as it has enough high points on its own.
The operation of the Ultimak AK Scout Rail is flawless. When replacing the gas tube on an AK one must wonder if the tolerances will be alright, if the piston will run with no interference, etc. I can tell you that with the two Ultimak AK Scout Rails I own I have had zero issue with the actual performance of the Ultimak AK Scout Rail. It cycles properly and efficiently. Being made of 6061-T6 hard anodized aluminum you can be assured that it will not degrade due to moisture and being made of aluminum it is inherently lightweight. It is attached via two clamps which attach to the barrel to secure the Ultimak AK Scout Rail in place. Throw some blue thread locker on the four screws that secure the rail to the clamps and you will be good to go for thousands and thousands of rounds. So what if you use corrosive ammunition? Well there are two ways to take care of cleaning your gun/Ultimak AK Scout Rail after using corrosive ammo. You could keep the rail attached and use a 12GA cleaning brush and mop and start with some water or simple green and follow it up with come good CLP like Slip2000. The second way, which is for the clean freaks like myself is to take the four screws off the top rail and take the Ultimak AK Scout Rail off the gun and clean it like you normally would an AK. I like thorough and this is my preferred method.
Doing so some might ask will affect the zero of the rifle right? It does not and let me explain why. The clamps that are on the barrel do not move, as they are in place and pretty secure by the handguard. So when you re install you are putting it in the same place it was. I have not seen anything glaring in relation to my zero by continuing to take off and put back on the Ultimak AK Scout Rail. So keeping zero is a non issue in my book. Some might add that due to the gas tube being integrated in to the picatinny rail that optics are affected by the heat. My answer is simple, get a high quality optic. Your airsoft type optics will not work, but something like a Aimpoint T-1 has no issue. I have throw thousands of rounds downrange and in 100 degree plus heat and have never had my T-1 not work. So, overall you will not go wrong with an Ultimak AK Scout Rail, it give you the ability to add the only two things an AK needs. A light and optionally an optic.