Optic location?

[jackinfl]

I saw a guys AR today and he had his EO mounted on the Sure Fire M-73 carbine rail. I told him this was not optimum as the sure fire rail is not free floated and can move and cause loss of zero.

Am I right? or am I on the wrong page?

Any advice or logic will be apprecaited.

Stay Safe,
Jack

[Hawkeye]

The Surefire rail is pretty solid as far as non free float rails go, but, I still wouldnt mount an optic on one.

[Snake RAH]

The top rail on the Surefire M73 (and all the ones that fit on an AR) is lower than the receiver rail. He probably has the front sight base take up 2/3 or more of the window.

Is it cowitnessed to his irons?

[Kisara]

Was this a flat top upper?

Sometimes, you have to make do with what you've got.
Or could just be his personal preference.

[Robb Jensen]

The optic out on the rail is fine, if both the optic is tight on the rail and the rail is tight to the barrel. He won't loose his zero unless the rail is removed and then reinstalled on the barrel. Actually whenever possible I like to mount a 1x optic as far out as possible, target acquisition with it there is very fast.

It's much more solid if mounted on a FF rail like a DD Lite Rail, LaRue or Troy. I like all three of these in that order.

[rob_s]

I wouldn't mount an optic on a Sureifre rail either. If, for some reason, I thought I needed my optic that far forward I would use a DD or LT rail.

The real question is, how much does this guy shoot? Does he like it because it works for him or because he thinks it looks the best for posting pictures on the internet?

[Stik]

I have a Surefire M73, or rather had it on a rifle, sitting in the parts box now. When the DEA got the RRA w/surefires, I thought that had to be a good set up and built a clone. That was my very first AR, right when the AWB sunsetted. But I took it off and parted out that rifle and have built a few others since then, but anyways the way a surefire rail works is the top portion of the rail is "locked" in place by set screws pushing it from the front of the rail back to the barrel nut, which also locks the bottom rail with the top, kind of like how troy 2 piece top and bottoms slide together, which it locks them together sort of. The set screws push the top rail back towards the barrel nut and push the lower rail towards the handgaurd cap. The lower portion of the rail is not as solid, or will move ever so slightly, but the top portion is very tight and solid and should be fine for an optic (1X). I didn't like it for the fact that it didn't freefloat the barrel, created uneven pressure on the barrel and it sat lower than the flattop rail.

From what I understand, they made it lower due to all the IR pointers and lasers the military uses and mounted up front like that made a little more room to see over the sights, but again, that is just what I heard and is not based on any documented info. I know my way around AR's but am by no means a cerified gunsmith or armorer, just a "extra bedroom/basement gunsmith" of sorts.

[jackinfl]

What would be the preferred way to mount an EO/Aimpoint out in front of the upper receiver if you need the upper rail space for a NV scope/device??????

The guy is a shooter he is on one of our aggressive units, and the AR is his support weapon when moving into position to set up his Bolt gun...Former Marine and a good guy.

I thought that a Free Float would have been the best way to go... I like the Larue products.

His AR is a SBR 10.5" Flat top. The reason he had it all the way forward was to mount a NV scope to the upper that he said will not fit if the EO is on the upper. He is also using an ARMS folding BUIS.

The rail is lower than the upper receiver. The set screws to secure the rail were not loc-tited on, when I asked if they were.

I did not see the NV device.

So, if the Sure Fire rail is secured with Loc-tite and is not removed from the gun it will maintain ZERO?

I will let him know and if the set up works for him and he can see past the FSB which will be taking up alot of his visual space it should be good to go.

Oh Yeah, Rob. This is one of the guys that I want to bring out in October...

Guys, Thank you for sharing your opinions and experience.

Stay Safe
Jack

[MX5]

Forward mounting on a FF rail is an excellent system. This goes back to Cooper's Scout concept in actual use. If the rail moves or is less than secure, then zero will suffer.