I need a recommendation for a decent free float forearm tube for my M&P carbine. I don't need a bunch of rail space and it needs to be INEXPENSIVE but not junk. Also, how about one that can be installed without removing the front sight.
Midwest Industries T series Gen 2
That won't work. The OP is going to need a 2-piece like a DD Omega.
Otherwise, the barrel delta nut has to be removed to free float the barrel.
Something I would be thinking about real hard if I were putting together a carbine right now. . .
DD Omega carbine handguard - $270
Magpul MOE handguard - $30
Mount-n-slot light mount for MOE - $60
QD sling socket installed - $26
Surefire G2L - $55
$100 in your pocket for whatever else you want - $100
A non-free floated carbine will still put the lights out at 300m all day long. If you know you have a need for a floated handguard then by all means go for it. But if you just want one because they're the hotness and you need to have it . . . well, you can get better value for your money, I think.
If you ever use a sling as a shooting aid, you can shift POI enough to miss that target at 300m.
Or if you ever brace the handguard, or something attached to the handguard, against a barrier/barricade as a support.
In other words, many real world shooting situations/implementations benefit from a free floating rail.
Even if you cheat and use a bipod, you're going to want a free floated rail to attach it with.