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.

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.

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.)

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").)

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...

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.

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!

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.

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.

Thanks to a tip from lumberjack149, I looked into the comparative weights of the Vinci extended mag tubes out there. The 10rd RCI X-Rail I have weighs 17.1oz fully assembled, no ammo, and Nordic tells me their total-of-10-rounds MXT-VINCI-7 weighs 14oz fully assembled, no ammo. I purposefully compared apples to apples with both tubes being 10rds total capacity each. Fully assembled means in both cases: the part of the tube that fits into the foregrip with the twist-lock collar and release button (holds 3 rounds), the part of the tube that extends out the front of the foregrip and that holds the extra rounds (7 in both cases), spring, end cap, and follower. Thus, I can reduce the overall weight of my Vinci by just under 3oz. by swapping tubes. This may solve the intermittent problem with short-stroking low-recoil slugs. Hopefully this helps someone. On a side note, I am looking at the Lancer carbon fiber extension tube, which is ridiculously light, but it requires the factory Benelli Vinci 5-rd mag tube as a base, and Benelli refuses to sell these to anyone except law enforcement (thanks to Obama's signing statement of some bill a couple of years ago regarding importing of sporting shotguns). So I will likely not ever be able to fully-assemble or test the Lancer tube. The Benelli factory 5-rd tube is widely available in Europe and comes standard on the Benelli Italy Vinci SpeedBolt model.

Thanks for the advice--I've looked at Atlanta Arms & Ammo's website, and when I try to use their Dealer Locator page, it produces results that are all the way across the country. I don't know if this means there aren't any dealers nearer the West Coast at all or if their website is just broken. So, in short, are there any shops that carry Atlanta Arms' ammo near or in SoCal? Based on all the great advice in this thread, I think I will probably be standardizing on Hornady Steel Match 75gr after I replace my barrel. Price is right and its ballistics are probably not that different than the 75gr stuff I'm using now. Thanks!

Thanks--will do!

A good ballistic calculator/computer software will allow you to calculate precisely where to expect the bullets to hit at any point along their trajectory. Thus, you could punch in that you have zeroed at 200yds, input ALL your ballistic data (especially chrono speeds and ballistic coefficient), and then you can confirm that the software's calculations for POI are correct at various distances up to 200yds (try 50, 100, 150, 200). Once you are certain the software has got your system down and can accurately predict the trajectory beyond 200yds, you can then figure out where on your scope's vertical axis those 300yd, 400yd, 500yd POIs should be and see if they really line up with the expected stadia lines. In other words, you model what you do know and can confirm in the real world (POIs at all ranges up to 200yds), you test the model against the real world (up to 200yds), then you trust the model to be correct for what you don't know and can't confirm (ranges greater than 200yds), and you use the model to determine whether your scope's stadia lines are right or not. IIRC, Knights Armament makes a ballistic computer app called Bulletflight for Android or iOS, but I have not used it, so I don't know if it will do what I described above. I expect it would, since it is pretty hardcore.

I'm really impressed by the quality and ergonomics of the Yugo M92s. You'd have to build one as a pistol or SBR or pin a ridiculously long brake on it, but the build quality is outstanding, and it's just fun to shoot. I can hit a 10" steel plate out to 200yds consistently with a 2MOA red dot on one--good enough for the local tactical matches but not good enough for the local 3-gun matches. Keep in mind that this is with a 10" barrel and crappy steel cased Russian surplus, not the higher-quality brass-cased ammo.

I think you'll simply have to figure this one out by trial and error. The trade-off between FOV and "seeing around the tube" (i.e. situational awareness and seeing the next target in one's periphery) as well as the "sharp dot" is something that only you can arrive at. I have tried pretty much every location on the rail, from all the way out to all the way in, and I arrived at a spot just forward of where I would ordinarily place a 1-4X scope. This ends up being about 4" between my eyeball and the subjective lens.