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AR Quad Rails

Posted: Mon Jan 12, 2015 11:17 pm
by J
Working on a new AR build and will be putting a FF 15" handguard. Ive been looking at the Midwest Industries T series or one of the Gen 2 versions. Anyone have any thoughts on MI? What brands do you think make the best FF handguards? Also, I need the inside diameter larger than 1.25. Thanks.

Posted: Mon Mar 16, 2015 7:43 pm
by J
So I went ahead and put on a MI Gen2 SS Series FF rail. For some reason the quad rail bows in the middle. It sits ALMOST flush with my upper receivers rail (barely noticeable). When I put it upside down on a flat surface, so its laying on the rail, you can see that its not totally flat. Is this normal? This is my first FF quad rail I put on.

Posted: Tue Mar 17, 2015 4:21 pm
by SR9
I would say it is defective. The rail should be square on all sides, at leat the ones I have seen were.

Posted: Tue Mar 17, 2015 7:54 pm
by JohnB
is it metal..alloy..etc or a polymer ?

Posted: Wed Mar 18, 2015 4:06 pm
by SR9
JohnB wrote:is it metal..alloy..etc or a polymer ?


Its T6061 Aluminum.

Posted: Wed Mar 18, 2015 10:09 pm
by JohnB
they say its CNC machined so it should be pretty close...how much off are you talking ? has to be some tolerance...did you try it with a real straight edge or another surface that should be flat ? that can give a false reading too