Lets discuss FF rail differences for a moment

[jasonb]

I will start this thread by saying that I only have experience with Vltor, Troy and a KAC RAS.

I'm plotting another upper build and I am to the point of choosing a rail system. We all know that the major players are LaRue, Daniel Defense, and Troy(there are a couple others too, but thses are the most prolific).

The prices are similar, but the attachment methods vary. My question is what makes a Daniel Defense carbine length rail or a LaRue better than a Troy MRF?

Is it the materials?
Is it a weight issue?
Is it a rail spec issue?

What makes a clamp on, minimal gunsmithing required forearm inferior to a rail that the front of the rifle must be disassembled to install?

Thanks!

[SWATcop556]

This is a very good place to start:

http://www.tacticalyellowvisor.net/8343/41127.html

Rob knows his s**t. :cool:

[rob_s]

Thanks SWAT! This may help too.
http://spreadsheets.google.com/ccc?key=pwswheghNQsFnUZMkZNF2DQ


to the OP, my take on two-piece vs. one-piece is that one is always better than two when it comes to "structures". more pieces = more joints and more joints = more potential failure points. More joints also typically = more weight and in the case of the Troy MRF it's installed weight is typically +/- 5 oz. more than the DD M4 or Lite.

[LMTRocks]

Since I have a little experience with both DD Omegas and the Troy MRF rails I'll throw $0.02USD towards you. I wanted more real estate on my LMT so I found a great deal on the Troy MRF-R after I had a DD Omega 7 installed. I took the omega off and sold it, but after installing the Troy I realized that I should've just spent the extra $$$ on the Omega 12. It attaches so much faster than the Troy does, as it's really goes in like a normal set of handguards, and all you do is tighten the allen screws against the barrel nut. Literally 20min, maybe less if you're super proficient with that little allen key. The Troy however, required the D-ring to be cut off, and installing the rail showed me that my barrel nut does not allow the rail to sit perfectly flush with the top of the receiver. It was literally a 1/16" lower when I tightened the clamp. If I kept it flush, it would wobble a little bit with my VFG. Unacceptable. So, being without a D-ring I went to a machine shop and they gave me some brass, very thin, not sure what spec, and I made some "shims" that reside inside channel where the barrel nut goes. I also had to shim under and over the gas tube to keep the rail from "see-sawing" or getting torqued out of alignment from the upper receiver. It took me about 10x to find the correct amount of shimming to keep the rail tight and in alignment. I didn't have a problem like that with the omega 7, and every weapon I build from here on out will have an omega, LMT MRP, or VLTOR VIS setup. Don't get take this the wrong way---you may get a Troy that locks up perfectly the first time, although I've seen other guns with the same rail have alignment issues and to me if you're using flip up sights a forward mounted red dot the rail should be not more than a 64th off, but a 16th is just too much.