I just bought a 512 and I was going to get the Larue mount to raise it up just a little for lower 1/3 cowitness.  I plan to use a ARMS BUIS on my LMT M4.  I have also been looking into the VLTOR FF rail.  Will the Eotech sit too high or just right on the CASV?  I have read that the ARMS SIR will put the Eotech too high and I was wondering if this is true as well.  Any help is appreciated.

I have done a search, didn't find anything.

Quoted: I just bought a 512 and I was going to get the Larue mount to raise it up just a little for lower 1/3 cowitness.  I plan to use a ARMS BUIS on my LMT M4.  I have also been looking into the VLTOR FF rail.  Will the Eotech sit too high or just right on the CASV?  I have read that the ARMS SIR will put the Eotech too high and I was wondering if this is true as well.  Any help is appreciated. I have done a search, didn't find anything.

The Vltor is the same height as the ARMS SIR. So yes, it will sit too high.

I just got my Vltor CASV-EL and it looks like .50 height.  I noticed in one of the pic threads that Stick mentioned his Aimpoint would not co-witness with the Vltor either.

Why is it that I see guys with the cantaleiver (sic? who cares, it's late) mounts and the ARMS Aimpoint mount w/ riser that, look taller than the Vltor, but they are co-witnessing?  What's the deal?  Is there no CW with the Vltor??

Quoted: Quoted: I just bought a 512 and I was going to get the Larue mount to raise it up just a little for lower 1/3 cowitness.  I plan to use a ARMS BUIS on my LMT M4.  I have also been looking into the VLTOR FF rail.  Will the Eotech sit too high or just right on the CASV?  I have read that the ARMS SIR will put the Eotech too high and I was wondering if this is true as well.  Any help is appreciated. I have done a search, didn't find anything. The Vltor is the same height as the ARMS SIR. So yes, it will sit too high.

You mean to cowitness,right?  Got an ARMS catalog today and it shows an EOTech mounted on the forearm end without the additional rail spacer and it appears to co-witnesses perfectly?  

The rails on a SIR#50, 58 , and 58MOD, fwd. of the receiver, the portion directly above the handguards, are not the same ht. as the reciever rail; it's higher....so the EOTech co-witnesses on that rail, but not, the portion of rail sitting on top of the receiver rail....

/S2