hey fellas, i just ordered the ap4 stock for m lr-308t, should be coming in soon, ill tell you more when i install it. anyways i was looking at the quad rail free float tube, carbine length, they have it! ill probably will be buying that next week. for me i would get the high rise rail. my question is . if anyone hase ever taken off there free floats before. im gonna need to install it when mine comes in. i just have the ribbed carbine on mine now and was wandering what needs to be done for instalation. does the gas block have to come off? school me up fellas. im a newbee in the free float department.