Introducing the RUKH adjustable offset mount!

[Valhalla]

your windage will be good at your zero distance and increasingly off as you get farther from your zero distance.

I still don't understand this part. Mechanically, windage should remain unchanged regardless of the target distance. If there is no wind, the bullet will not magically fly to the side just because your RDS is canted. The law of gravity will dictate it always drops vertically... unless Coriolis effect is in-play (and I would love to see someone shooting past 1,000 yards with an RDS. lol) Therefore, distance should have no bearing on windage, only elevation.

Now, just to be sure... (yes I know it's a stupid question but better safe than sorry) if your offset RDS is 45 degrees off axis, do you not shoot your gun at 45 degrees when using the RDS? And if so, do you not zero the offset RDS with the gun also held at 45 degrees (aka in the exact same position of how you would be shooting when using that RDS)?

[GH41]

I still don't understand this part. Mechanically, windage should remain unchanged regardless of the target distance. If there is no wind, the bullet will not magically fly to the side just because your RDS is canted. The law of gravity will dictate it always drops vertically... unless Coriolis effect is in-play (and I would love to see someone shooting past 1,000 yards with an RDS. lol) Therefore, distance should have no bearing on windage, only elevation.

Now, just to be sure... (yes I know it's a stupid question but better safe than sorry) if your offset RDS is 45 degrees off axis, do you not shoot your gun at 45 degrees when using the RDS? And if so, do you not zero the offset RDS with the gun also held at 45 degrees (aka in the exact same position of how you would be shooting when using that RDS)?

Think about the old illustration of a bullet path when zeroing. Let us say we use a 50-250 zero... The bullet crosses the point of aim twice. Once at 50 yards while climbing and again at 250 yards while falling. Now rotate the rifle 90 degrees so the elevation adjustment becomes windage. The bullet path only crosses the point of aim one time. The further the bullet travels past the POA the further away from the POA it will impact the target. If the offset sight isn't perpendicular to the bore the bullet path can only cross the POA one time. Why do you think the long range precision shooters have bubble levels on their rifles?

[MegademiC]

Think about the old illustration of a bullet path when zeroing. Let us say we use a 50-250 zero... The bullet crosses the point of aim twice. Once at 50 yards while climbing and again at 250 yards while falling. Now rotate the rifle 90 degrees so the elevation adjustment becomes windage. The bullet path only crosses the point of aim one time. The further the bullet travels past the POA the further away from the POA it will impact the target. If the offset sight isn't perpendicular to the bore the bullet path can only cross the POA one time. Why do you think the long range precision shooters have bubble levels on their rifles?

This has noting to due with being perpendicular, but how the rifle is mounted and sighted in.

If you hold poa directly over the bore, inline with gravity(and its sighted in like this), no windage holds.

For zeroing, if you hold the optic perpendicular to the ground, sighting in would be the same as any other optic.

[LowSpeed_HighDrag]

Think about the old illustration of a bullet path when zeroing. Let us say we use a 50-250 zero... The bullet crosses the point of aim twice. Once at 50 yards while climbing and again at 250 yards while falling. Now rotate the rifle 90 degrees so the elevation adjustment becomes windage. The bullet path only crosses the point of aim one time. The further the bullet travels past the POA the further away from the POA it will impact the target. If the offset sight isn't perpendicular to the bore the bullet path can only cross the POA one time. Why do you think the long range precision shooters have bubble levels on their rifles?

Isn't this a non issue if the shooter zeroes and shoots at the same angle everytime with the rds? We have bubble levels to ensure we shoot at the same angle each time. I'm struggling to see your issue...

[caporider]

Isn't this a non issue if the shooter zeroes and shoots at the same angle everytime with the rds? We have bubble levels to ensure we shoot at the same angle each time. I'm struggling to see your issue...

Not sure why I'd want to have find a precise angle at which to hold my rifle to use my offset RDS... Isn't it faster and easier just to cant your rifle to wherever your RDS is level in your field of view?

I'm also still processing the mechanical offset issue... Are you guys saying that if I have an offset RDS that is not perpendicular to the bore that I can just hold the dot anywhere in my FOV and as long as the dot is over the target I can just hold over as usual at closer ranges and have POI still work correctly?

[jpmuscle]

Some of you guys are really over thinking this


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[Valhalla]

Some of you guys are really over thinking this


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My thoughts exactly... Just didn't want to be the first one saying it. LOL But I do enjoy the occasional academic discussions...

[Valhalla]

Now rotate the rifle 90 degrees so the elevation adjustment becomes windage. The bullet path only crosses the point of aim one time

Actually it doesn't. If you do 50-250 zero, and then turn the rifle 90 degrees, the bullet will never cross path with the sight axis. This is why with long-range shooting, you always zero (and shoot) with your optic directly over bore.

Not sure why I'd want to have find a precise angle at which to hold my rifle to use my offset RDS... Isn't it faster and easier just to cant your rifle to wherever your RDS is level in your field of view?

Personally I think there is an even easier way. 1. Rotate your wrist and find out what is the most natural way you would hold your rifle at "offset" position. 2. MOVE the RDS until it sits directly over the bore. 3. Sight it in.

Ever heard people say "close your eyes, get a good cheekweld, and then position your scope until it's eye-relieve matches your head position"? You never adjust yourself to your optic; you adjust your optic to you. Offset mount shouldn't be any different. Whether the RDS is level or not is irrelevant; what you should aim for is that the RDS naturally centers itself at each person's natural offset hold of your own rifle. From there, you sight it in just like everything else, and leave it alone. Your body will remember how to hold your gun, and the point of impact will not require any mechanical offset or calculation. The point is, always zero the way you will be shooting the gun, and always shoot the gun at YOUR most comfortable and natural position. This will naturally results in consistency, improved speed, and better accuracy.

[Valhalla]

But I do enjoy the occasional academic discussions...

So back to the academic-aspect of things. If you are using the Rukh and absolutely must hold the RDS "level" (parallel to horizon), within the intended range of adjustments you would cause your rifle to tilt up to ~10 degrees away from perfectly vertical. This translates to, at most, 0.5 inch mechanical windage offset at the muzzle. Assuming ballistics similar to M855A1 (62gr, 3150 FPS, ~0.3 BC) at 1.93 height, zero at 75 yards, and a 3.25-MOA RMR, your point of impact from 50 yards all the way to ~300 yards would be ENTIRELY within the dot (+1.56MOA @50yd, -0.7MOA @125yd, +1.32MOA @300yd):

M855.jpg

Subsequently, your windage shift, at the aforementioned 0.50 inch point-blank mechanical offset, would result in 1.5 inches shift at the opposite direction at 300 yard (0.5 MOA). So... Worst case scenario, at 300 yards, your point of impact would be ~4 inch low and 1.5 inches off the side from the center of your dot. Plenty good enough to hit center-mass, and again entirely covered by the 3.25MOA dot (which would have a 9.75" diameter at that distance).

Long story short, if you adjust your mount per our recommendation, the 4" drop will still be there but there will be no windage shift at distance. Even if you decided NOT to hold your rifle that way, and go with the RMR "level", your point of impact from 50 yards all the way out to 300 yards would still be entirely covered by the RMR's 3.25MOA dot. Such minor differences would not concern me... not for an offset RDS anyway; if you need to shoot a pistol off of a suspect's hand while he/she is holding someone hostage, get on with your primary optic. The offset RDS is not for this. But if you are doing surveillance with your main optic already set at high magnification, and some nutjob jumps out of the alley screaming "allahu akbar" at you, holding the offset RMR "level" and calculate windage will be the least of your worry... you just need to make sure at ANY distance you may be using the offset RDS at, a bloody hole (or two, or three) is going to appear wherever your dot is. And most offset mounts on the market, regardless if they hold the RDS perpendicular to the sight/bore axis, can do that for you.

[MegademiC]

Not sure why I'd want to have find a precise angle at which to hold my rifle to use my offset RDS... Isn't it faster and easier just to cant your rifle to wherever your RDS is level in your field of view?

You dont. Its no different than any other red dot. You dont worry about holding your rifle perfectly level with an rds, so dont worry about it with this

I'm also still processing the mechanical offset issue... Are you guys saying that if I have an offset RDS that is not perpendicular to the bore that I can just hold the dot anywhere in my FOV and as long as the dot is over the target I can just hold over as usual at closer ranges and have POI still work correctly?

the dot doesnt know the base is not perpendicular to the bore.
The dot and bore are 2 points fixed in space, forming a line.
The only influence to bullet trajectory in relation to the poa is how that line is pointing in relation to the ground (gravity).

if the dot-bore line is perpendicular to the ground, its exactly the same as a normal rds setup - regardless of where the base of the mount is pointing.