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Horus Vision ASLI. It is any good?

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Unread 05-04-2010, 01:13 PM
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Join Date: Jan 2003
Location: The rifle range, or archery range or behind the computer in Alaska
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Horus Vision ASLI. It is any good?

Looking for info, opinions and/or experiences with the Horus Vision Angle Slope Level Indicator.


Thanks for any help.

Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.

Last edited by Michael Eichele; 05-04-2010 at 01:19 PM.
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Unread 05-06-2010, 12:03 AM
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Join Date: Mar 2006
Location: Southwest Oregon, Douglas County
Posts: 62
Re: Horus Vision ASLI. It is any good?

Cant beat it for the money, well made unit. Had small issue with sun glare at certain angles. The degree marks are easy to see. They come with a nice cover.

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Unread 05-06-2010, 09:22 AM
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Join Date: Oct 2007
Location: Patagonia Mountains, Arizona
Posts: 770
Re: Horus Vision ASLI. It is any good?

This isn't a comment on the Horus Vision ASLI specifically, only on whether a rifle mounted elevation meter is needed at all.

When taking any shot there are several variables which need to be determined. I'll assume the characteristics of the ammo and rifle are known. The more important variables are:

1.Distance to the target. That can be line of sight or "map distance" but they're different.
2. Wind deflection derived from the continuous wind vector and bullet drag over the trajectory. The hard part is determining the wind vectors.
3. air density
4. elevation angle to the target

Less important (but maybe needed for very long range are cartridge temperature and azimuth.

Before buying instruments it's worth considering how much each of those affects your accuracy versus distance and what equipment is needed to measure those with the necessary accuracy.
For moderate range hunting (500 yards?) your senses and practice can be sufficient.

Laser rangefinders can easily give the distance to the target to +/- 1 yard. Maximum range is just what you want to spend on the device. Visual estimation using stadia range finders (like mil-dot) may be practical if known sized objects are in the field of view but typically have a 10% or greater error. The needed accuracy increases with more the square of the distance.

Wind speed at the shooters location can be measured with a pocket anemometer or estimated with practice by the "feel" of the wind but downrange winds are even more important than at the shooters location for shooting over about 600 yards. With lots of practice one can get fairly good at estimating wind deflection from mirage, plant movement, and windblown particles, but there are no affordable instruments which can measure wind accurately other than at the shooters position. Visual wind estimation is more difficult in mountainous terrain than on flat ground and also more difficult in low light.

Those two measurements are the most important to accurate shooting.

Air density measurement has become fairly simple to measure with electronic or mechanical devices which cost $100 to $200. But one can do a decent job of estimating air density by estimating the temperature, altitude and guessing at the barometric pressure based on the weather conditions then using a lookup table. Shooting accuracy is not as sensitive to air density as to range or wind deflection. Air density affects the drag on the bullet, but it's a secondary effect.

Likewise, most people can estimate the target elevation angle within 5 degrees with a little practice. Since the data is only useful if you've memorized multi-variable ballistics charts (or enter it manually into a computer) is a scope mounted inclinometer the best way to measure angle? I use a LTI rangefinder which gives the elevation angle with each distance reading. That seems like a more sensible place to locate the inclinometer to me. For most shooting a 5 degree estimate is sufficient for the error to be smaller than wind estimation errors. For shooting on reasonably flat land elevation angle can be ignored to around 1000 yards.

I've never considered that I need an elevation meter mounted on my rifle. If there was a "complete" scope based rangefiider that measured crosswinds downrange then the ability for the scope to also measure air density and target inclination angle would be useful for internal calculations by the scope's computer.

I'll not be buying a Horus ASLI. I do have a Horus Falcon riflescope with the H37 reticle and like it very much. It gives accurate windage and elevation holdoffs with no knob twiddling or click counting.

Last edited by LouBoyd; 05-06-2010 at 09:35 AM.
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Unread 05-06-2010, 11:53 AM
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Join Date: Jan 2004
Location: Blackfoot, Idaho
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Re: Horus Vision ASLI. It is any good?

I quickly plowed through the users manual to see if there are any deal breakers.

Found non but had to laugh about about it being 'self-adjusting'.........like gravity doesn't work!

As LouBoyd mentioned if your LRF provides this info, then who needs one.

But if your LRF doesn't provide the info this type of device is a must have in my book.

This one seems sturdy enough though time will tell.

I wasn't readily able to determine the weight of the device and have a bit of concern of how it is mounted to the three mounting options.

It appears to slide onto the mount in a horizontal fashion with a friction type set screw to secure it.

Would not it be better if it slid vertically onto the mount? I'm thinking of big boomers that may require two sets of rings to secure the scope.

The only reason I don't have such a device at this time is the mounting concern.

Last edited by royinidaho; 05-06-2010 at 12:02 PM.
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Unread 05-09-2010, 10:20 PM
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Join Date: Jan 2008
Posts: 1,132
Re: Horus Vision ASLI. It is any good?

Micheal Eichele,
I purchased a ASLI about 2 months ago and love it. It is a very good unit for the money. I will admit a little bigger than I'd like, but at half the price of an ACI with a spirit level and mounts its a great peice of equipment. I shoot a 10lbs .338 RUM and it has no problems staying put thus far.
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Unread 07-07-2012, 06:37 AM
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Join Date: Feb 2011
Location: N. Texas and S. Africa
Posts: 8,094
Re: Horus Vision ASLI. It is any good?

Since we have someone currently looking at ASLI's I was doing some googling and found this thread so I thought I'd resurrect it.

Yes your laser rangefinder (assuming you have the higher end models) can also give you the angle and cosine.

Until it fails due to breakage or dead batteries.... .
Without the First and Second Amendments the rest of The Constitution is Meaningless.
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Unread 07-07-2012, 11:27 AM
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Join Date: Jan 2008
Posts: 1,132
Re: Horus Vision ASLI. It is any good?

Im still useing mine. Even if i get a new LRF, i will keep it on. Just like i would never go on a hunt without knowing how to use my reticule to range. Electronics fail sometimes.
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