EER mounts that have even more eye relief for NTCH shooters?

[dchang0]

There's a problem that's been plaguing me for a while. I'm a Nose To Charging Handle shooter because I use the charging handle to index a consistent cheekweld. When forced to back off of the charging handle, I find that parallax becomes an issue because I'm sort of "floating in space" without a kinesthetic reference.

But, there don't seem to be many 30mm "extended eye relief" scope mounts that can really mount my scope far enough forward for me to touch my nose to the charging handle AND get the proper eye relief. I really need to mount my scope about 1/4in. further forward than it is right now to get it perfect.

I have a Larue SPR-E LT139 mount, and while it says that it's a 3" extension, the reality is that the width of the front scope ring detracts from this amount. Thus, two different scope mounts can both say they are 3" extension, but the scope itself could end up further forward on one mount than the other.

The dimension that really matters for comparison between mounts is the one in the attached drawing I made. Let's call it the "Actual" Extension, since it takes out the dimensions that don't count towards the forward position of the scope. I mount the scope mount all the way forward at the very front edge of the upper receiver (not going over onto the handguard). Then, I push the scope as far forward as it will go, which is almost always determined by the rear edge of the front scope ring, where the turrets will butt up against.

On the Larue LT139, that "Actual" Extension measurement is 2.14" I basically need this to be 2.40" or 2.50", but I'll take even as low as 2.25" because every bit counts.

Can you guys help me find a new scope mount by providing the crucial measurement from your various brands? It has to be 30mm and have a centerline between 1.50" and 1.44" above the rail (1.50" is preferred). And it would, hopefully, have greater than 2.14" for the measurement indicated.

Thanks very much! I'm sure other NTCH shooters are dying to find this info too. Oh, and if you happen to know the mount's weight, that would help too.

Edited September 24, 2015 by dchang0

[dchang0]

To start off this reference, here's the "Actual" Extension for the Aero Precision Ultralight SPR mount (nominal extension of 2in.):

1.58in.

Yeah, so I bought one of these and was sorely disappointed to find out that it just doesn't work for me. So it'll go up on ebay soon enough.

[Dan Sierpina]

I'm a stock crawler, and found the Vortex 3" offset to work well for me. The distance between the rings is pretty wide, and I found that to help. I also went to a Luth adjustable stock, and when a stage has prone shooting, I extend the stock all the way.

[ac4wordplay]

OP:

Consider using separate rings and rail - it's one solution to your problem.

This started as a ARMS S-EX rail, and was cut to desired length. TSW rings were added. Lots of eye relief is possible, and can be adjusted more than one-piece mounts. Optic height is "adjustable" by selecting rings of different height. My low rings result in a height of ~ 1.45" above bore.

A similar result can be achieved with rails by IOR Valdada, and GG&G.

I've been happy with all these products and have used this set up for more than ten years. Lots of matches, travel, and dump barrels. Rock solid.

Best,

ac

[ac4wordplay]

Odd that the pic displays upside down. Sorry.

[OPENB]

I did the same as ac, except I used a Rock River Arms Scout rail & Warne medium height rings. Downside is it's heavier than a Larue or ADM all-aluminum mount and was not return to zero. But it was very solid & held zero without issue. It's on my 22 upper now.

I found the same issue as the OP with the Aero SPR. just wanted a tad more ER. I got an ADM Scout X with one throw lever. It has the extra ER I was looking for. I'll measure the distance between the rings this evening.

[dchang0]

Thanks for the tips, guys. "Actual" Extension measurements on the ADM Scout X and Vortex 3" (nominal) extension mount would be awesome, AND they'll help future buyers do the math on their setups.

That idea with the separate rings and rail is a good one--although the weight is probably a couple whole ounces higher than a one-piece mount. I'll treat that as my last resort option and keep looking for a one-piece mount. No worries about the upside-down photo, ac4wordplay--the point comes across crystal clear--thanks!

[dchang0]

Amazon answers say that the Vortex 30mm mount with 3" nominal extension has the rings 2.5" apart, which is pretty far. This guy Tristan says:

http://www.amazon.com/Vortex-Cantilever-Mount-Absolute-Co-Witness/dp/B009QJLBDQ

"Between the rings is 2.5 inches from the outsides of the rings measures 4.75 inches width of individual ring is just shy of 5 eigths of 1 inch. Base is 3.25 inches in length. 6.75 inches in total length. Hope it helps

Tristan answered on July 14, 2015"

If the numbers are correct, then the "Actual" Extension is PROBABLY:

3" - 5/8" = 2.375" <=== Only correct if the 3" nominal extension is measured from the front edge of the base.

OR

6.75" - 3.25" - 5/8" = 2.875" <=== Can't possibly be right, even though it should be. Should be under 2.5" (distance between rings).

I guess Tristan's measurements are wrong.

Edited September 25, 2015 by dchang0

[OPENB]

My ADM Scout X is 2 1/4" between the rings. But, the rear ring is way forward. It sits right above the last slots on the upper, allowing the scope to be set way out front.

[oak hill]

I too have the same issue and setup my mounts so they hang off the receiver in the front, with the locking lug in the last possible rail slot

[ac4wordplay]

That idea with the separate rings and rail is a good one--although the weight is probably a couple whole ounces higher than a one-piece mount. I'll treat that as my last resort option and keep looking for a one-piece mount. No worries about the upside-down photo, ac4wordplay--the point comes across crystal clear--thanks!

You're correct - the two-piece setup will typically weigh more than the one-piece units.

I found the weight difference insignificant, and due to it's location it doesn't really change my rifle's balance point. For me, the trade-off was worth it - I was able to achieve tons of eye relief adjustability. I get perfect eye relief fit for any/every scope I've put on.

[dchang0]

My ADM Scout X is 2 1/4" between the rings. But, the rear ring is way forward. It sits right above the last slots on the upper, allowing the scope to be set way out front.

Based on the photos and the reports of "distance between the rings", the Vortex 3"-extension mount probably beats the ADM Scout X.

If the distance between the Vortex's rings is really 2.5" then the actual extension may really be 2.5", since the Vortex's rear ring appears to be right up at the front edge of the base.

You report 2.25" for the distance between the ADM Scout X's rings, and the rear ring is not quite up to the front edge of the base. The Actual Extension may be the same or even less than the Larue's 2.14"

We definitely need actual measurements to settle this guesswork...

Edited September 28, 2015 by dchang0

[dchang0]

I got this helpful photo from a good buddy.

The mounts are all held with the front edges of the bases lined up with each other.

From top to bottom:

ADM Scout-X

Larue LT139

PRI Gator Grip #05-068-30H

Bobro Precision Optic Mount, Extended

He says the ADM, Larue, and Bobro all pretty much have the same "Actual" Extension forward and that the perspective of the photo can be misleading (making the Bobro look better).

Obviously the PRI just destroys the others. It probably extends even further than the Vortex. Note that it is built a lot like a separate rail + two rings.

But the weight has got to be insane with all that aluminum bulk.

(I can confirm from the specs on Bobro's website that their extension is likely the same as the Larue's. They say that the inside distance between rings is 2.15", and if the rear ring is all the way at the front of the base, as it certainly seems is true, then the "Actual" Extension of the Bobro would be the same as that for the Larue LT139 (2.14").)

Edited October 2, 2015 by dchang0

[dchang0]

Got these "Actual" Extension measurements from my buddy:

PRI Gator Grip #05-068-30H

Almost 3"
9.8 oz

Bobro Precision Optic Mount, Extended
2 1/8" (Probably equal to the Larue or a few hundredths shorter.)
7.7 oz

ADM Scout-X
Just over 2"

(Probably due to the rear ring not being all the way up flush with the front edge.)

[dchang0]

Add one more to the list of EER one-piece mounts. I went to SHOT 2016 and saw the Precision Reflex, Inc. "Cantilever Mount" here:

http://www.precisionreflex.com/Detail.aspx?PROD=186502&CAT=4275

It has 2 5/8" of "Actual" Extension as measured on the demo units they had at the show. The weight per their website is 8.3oz. The thumbscrews for mounting look pretty heavy--replacing them with the optional lock nuts would probably save some weight.

[dchang0]

I ended up buying the Precision Reflex "Cantilever Mount." Check out the photos--this sucker has WAAAAY more "Actual" Extension than the Larue LT139, exactly as expected from the measurements I took at SHOT.

In the photos, both mounts are shown flush with the front edge of the upper receiver, without crossing over onto the handguard.

The Precision Reflex mount is NOT QD, like the Larue.

Edited June 2, 2016 by dchang0