Think about your AR pistol/ PCC/AR15 that's going to be used in an urban environment.  If you're right handed, ideally, you'll want to use the right side of your cover.  But sometimes, you have to shoot around the left side.  Most people practice offhand shooting for this very reason.  But would you really switch to your offhand when shit got real?  I'm right handed, and I can't shoot for shit using my left hand.  Not to mention that my sling would get all tangled up switching from right to left and back.  The last thing I want to have to do is defend my life using my left hand!  I think that most people, when it came down to it, would keep shooting using their dominant hand.

If you hold the rifle tilted 45 degrees, then as a right handed shooter you can shoot around the left side of cover, or sweep a room, much better than you can while holding the weapon vertical.  If you haven't ever felt the difference, go grab your gun and see for yourself.  But you can only shoot this way, at 45 degrees, if you have an optic lined up there.  Surprisingly, I've found that holding the gun 45 degrees is also more comfortable on my wrist joints, and so why not hold it this way all the time, instead of just when shooting around left handed cover?  If you make this your primary way of holding the rifle, then you never have to worry about left/right sided cover so much at all because you can do both.

Now once you've got something like a RMR at 45 degrees, you've got room on your primary rail for a magnified optic.  Since you won't be using it for quick target engagement anyway, it does not need to be a heavy clunky LPVO...you can use a nice leightweight 2-7x or 3-9x under 10oz.  You'll have better and faster target acquisition at 1x using your 45 RMR than you would using a LPVO at 1x, you'll have a faster transition from 1x to high-magnification by simply turning the gun, in comparison to flipping a throw lever which requires taking one of your hands off the gun, and you'll have better glass at high magnification than you would using the LPVO.  To top it off, the weight of your RMR (1 oz), + mount (1 oz), + 10oz scope + 3.5 oz scope mount, you're still at 15 oz, which is significantly lighter than your LPVO + mount!

Give it a try, you won't be disappointed ;)

Look up Center Axis Relock shooting

Yes!  I didn't even think about it that way before, but basicallythe 45 degree offset RDS essentially allows you to use the CAR shooting style with a rifle

If you are wearing standard soft armor and especially plates, the CAR position while presenting a smaller target also exposes an unprotected COM vital and CNS area under your arms. The CAR stance for a contact range threat means it is a very big presentation of a very lethal if hit area and negates the armor's ability to absorb rounds.

I can understand it for someone that is not wearing armor, but some someone wearing armor it has a very large disadvantage in that regard IMO.

That's a very valid point. Although on the other hand, you don't need to poke your head as far out around a corner to shoot...

The AR platform is already somewhat compromised by the height over bore of the sights, scope, etc. In close, this makes for a significant offset if the optics are zeroed at 100 or 200 yards.

Now put the optic at a 45 degree angle and you have offset in both windage and elevation. Could be confusing for many. Sort of like roll-over prone at distance. Up close with a huge target it probably doesn't matter. But with varying distances and the need for possible precision, it could be a nightmare.

Roll the rifle 45* so the secondary sight is upright and above the bore like the primary was. No further offsets.

This may be an issue with offset RDS mounted on the side of a scope or scope ring, but with a 45 degree offset base mounted to the pic rail it isn't.  Once the gun is rotated 45 degrees so the RDS is now top dead center it has the same orientation as the primary optic when the gun is sighted normally.

I agree.  I have been running a 45* offset Kingslayer and a PA 1-6 Raptor for going on 2 years now and the system works excellent for me.  The scope is for 100 and beyond or a RDS backup on 1X.  The MRDS is for 2-100m but is a backup for the scope out to 300m.  My MRDS is zeroed at 36m and I know holdovers for my MRDS 0-100.  300 with MRDS is easy with aiming higher on the target but not above unless it's small which is a backup for the LPVO.  I know my Raptor is 2" high at 100 and on at other distances with BDC depending on ammo.  If you train and shoot with them even a little there is no issue.  

One Note.  When I rotate the gun, it is not a full 45*.  It is only rotated enough for me to pickup the RDS with eyes focused on the target and fire.  If I am off 1"-2" out to 100m it makes little difference. A RDS is not for precision up close, it is for speed.  I get shots off from low/ high ready and on target in under 1 second out to 50m.  No confusion for me between 2 different sights, a MRDS and a LPVO with totally different reticles.

As pointed out earlier it enables a quicker access to vitals. If I am going to train as I fight I want only one way the proper conventional way. YMMV.

Plus it puts you at a severe disadvantage when switching shoulders. Hard pass.

Honestly OP it’s just my shitty take on the subject but yes you want to switch shoulders if you want to shoot around the left side of a building


If you aren’t good at it just do it more often and you’ll get better at it

If you are stationary and have time to adjust that's fine, but if you are on the move or going through a structure with a lot of walls, it's probably not going to be feasible to keep switching shoulders.

Slow is smooth, and smooth is fast. This video illustrates how scary room clearing alone can be. I'll take the time to switch shoulders, it no slower than it's being made it out to be actually but your sling does need to be set up in a certain way to take advantage of it. Certain instructors, vetted instructors, actually teach exactly this.



Plus as was stated before, the offset exposes you to a CNS hit that the front plate cannot cover and can only be used on one shoulder so again, hard pass.

The offset still has it's place, but as a secondary and not a primary. I use mine if at max zoom and should an immediate threat come in close contact I can use it faster than switching views or trying to acquire through tunnel vision. And as a bonus, it helps for any weird firing positions like the low prone behind a vehicle as an example.

YMMV

I'm sure there are probably instructors teaching what you're saying, but the video you posted doesn't support that, but backs up my thinking and he's using a handgun which is much easier to transition than a rifle. You may or may not be able to control how long it takes you to breach an opening, but once you commit you can't control what's on the other side, so I'll stick with my dominant side until I can't.  At the end of the day you've got to do what works for you.

Regardless of the tool being used, the point is still the same that you don't go yolo by your lonesome and enter like you're on god mode in some video game and instead, slow is smooth, and smooth is fast. Plus using the dominant side is cool an all, until that dominant side exposes you leaving no cover or concealment But like you said, to each their own.