So my new LE6920 came with the magpul rear sight.  Cant say Im a big fan of it.  But is what it is.  Not a big fan for this very reason I was afraid of.  Even with high mount rings for my ARscope, there is no room to pop that thing up.  My goodness.....you would need to raise the scope so high it would be ridiculous.  For now, I slipped the magpul to the middle position in between the mount rings under my scope. where it is unusable, but in place on rifle  in case I ever had to chunk the scope, it would be available.  Why on earth Colt went to it I do not know.  What was wrong with original, tiny little rear one its had forever? Nothing!!!!  and you could always mount a scope AND STILL use it to see under the scope.  Think a very stupid thing to do.  Anyway, wanted to make sure I wasn't missing something???

Also, I sighted in the scope using a laser cartridge and want to store it and stash it.  So is it best I leave the original goop on it that came with it when shipped from Colt if Im not going to fire it and just re store it?  Or should I stip and clean and then store.  My feelings are whatever they used should be left alone.

Are you planning on the scope failing?

ETA:

I ALWAYS plan on the unexpected...

What about moving the scope forward?

What scope is it?

EDIT: Have you looked into something like this:

http://www.defensereview.com/diamondhead-usa-45-degree-offset-flip-sightsbuis-back-up-iron-sights-for-tactical-ar-15-riflecarbinesbrsub-carbines/

Oh yeah, I completely forgot!!!  I got a Bushnell AR 4-12 drop down zone scope.  High mount rings.  Still.....the front sight post mount that sits up on that arch in front, like an A shape (dont know the technical name of it as you can tell) is sitting right in the middle of my scope.  Yet mysteriously.....I dont see the darn thing.  At times I see kind of a shadow of it depending where my eyes are....but still, I would think it would block the whole scope and it doesn't???  It seems to the scope it is invisible?  Why is that?  As i was mounting it I was thinkimg gosh darn it, no way I can use this scope.  But it does fine.  Again, what am I missing here?

Thats a good idea the 45 degree mount!!

Wait...


So you're saying you're trying to see the front sight through the scope and you cant see it?

Im saying I am NOT trying to see anything but my target.  But the front mounted Post that sticks way up in the air on the front of the gun SHOULD be blocking my scope.  I mean its right there, blocking the whole thing. Yet when I look through the scope, I dont see it, like its invisible to the scope eyes...

Good god man. Calm the fuck down.

The magpul sight is supposed to be all te way to the rear with the scope sitting over it. Only ever to be used if the scope bites the dust. It's a "back up sight" for a reason. This is true of EVERY SINGLR back up sight used on ARs. High rings Arn't needed. Use rings that give you the lowest sight over bore dimension and the magpul sight is not to be used almost ever.

There are absolutely zero sight systems where you can use a magnified scope AND a flip up back up sight.

As to your conundrum about the "invisible" front sight. I'm not gonna take the time to explain. Too tired of the relentless noobs. Sufficient  to say its normal and expected when using a magnified optic. No one uses or expects to use the irons in conjunction a magnified optic. Hence why the rear sight not flipping up isn't an issue as It would be in the way.

Even with a flavor of carry handle no one would expect to be able to use irons while having a scope mounted on the thing.

Personal attacks removed & warning issued - Eric802

MBUS: Magpul Back-Up Sight

It folds down when not using it (such as when using a scope) and if needed, then it is deployed

BUT....its being USED as a MAIN rear sight and NOT a back up sight, as Colt defines it....and as threads on here already complain about.  Thus, if its going to be USED as a main rear sight, regardless of the term used by Magpul, then it is a MAIN, rear sight and not a back up sight.  But thank you, I did change my wording on that post to explain what I meant.  :)

If you must have a scope and BUIS; the only way that I know how to do it is to buy a carry handle and a scope that mounts on it that has the see through feature. You could also use the 45* side sights but they do not fit well under most scopes UNLESS you use extra high rings. There is also the possibility of adding a red dot sight above the scope but it is hard to do if your scope has a very high top turret.

My point was is that the standard little rear site that has always come with colts were just fine and could be used with a scope in place.  You could choose scope or if need be, in an emergency, just use the standard sites and look under the scope and still hit your target.  Colt adding the MBUS was a mistake in my opinion, as now, you have to pick one or the other, vs both.

I'm so confused.


If you have a scope on the rifle your sights are back up sights. Your primary will be your optic. If that fails you remove your optic and use the BUIS.

Thats the point right there.  You HAVE to remove the scope.  In a battle condition.....that takes time.  On my other AR's, I dont have to do anything.  The site is just mounted there from the factory.  I just look through it and shoot WITH my scope still attached.  yes I know, I can get quick disconnects...

What setups do you have on your other rifles that you can look through a mounted rear sight and a magnified scope at the same time?

Hes saying he can look "under" the scope through the mount some how.

OP, can we get a pic please? It may take a whole lot of misunderstanding out of this thread.

Also to the original poster. Is your old setup the tall carry handle looking sight?

What you are talking about does not exist.  The MBUS are standard height, the same height as pretty much all sights that are available for the AR.  Having the scope mounted high enough to be able to use irons below it would require mounting the scope over 3" above the bore which is ridiculous.  If you want irons that are immediately accessible then 45degree irons are your only option.

Is your scope mounted on top of a carry handle?

It exist if he was using a carry handle sight I believe. I think the problem is that he now has a flat top receiver.

Sounds like you need some Counter Sniper scopes. They're so good, you'll never need a BUIS.

Sorry guys.....I was getting something to eat.  In reading all your posts....I realize the problem.  YES, my other 2 have carrying handles and this is the first flat top I have bought.  Now that I read what you all are saying....then there is NO choice other than a flip up OR a scope.  I assumed, was trying to google it now, that they made a flatop IRON site that permanently attached.  Do they not make that???  The MBUS is TALL...

But great job on reading in between the line :)

I was trying to politely help this guy.  


I agree that if you have a scope on your rifle... the back up iron sights (BUIS) are exactly that, a back up. If a time ever arises where "OH SHIT, the fluxcapacitor in the scope has a #87 malfunction" you could remove the scope (some sort of quick detach set up would be a good idea, if you were worried about this) and then you flip up the BUIS and go to town. If you don't want to detach the scope, which is understandable, the 45 degree BUIS could do the trick for you if you're into that sort of thing.

Please post pictures OP.

They are all that tall except for the micros. Even then you wont be able to see under your scope. And the magpuls are no higher than your carry handle btw.

That makes a lot more sense now.  

Plumber,  mounting on the carry handle has always been substandard.  A product of necessity. Mounting a scope on the flat top with the rear folded under the ocular allows you to have a more natural cheek weld and ends up with a better situation as far as height over bore is concerned.  This allows for a much more usable zero without the drastic convergence issues.   The lack of ability to use your rear with the scope mounted is more than made up for by it's benefits.

To answer your question, I don't believe that any product exists that will do what you want it to. The MBUS rear is identical in height to the rear sights on your carry handle.  They need to be this height to use the front sight.

It's been referenced already but most people that wish to use a secondary sighting system with the scope attached will use 45 degree sights or red dots.

ETA : You can use a detachable scope mount such as the LaRue LT-104, or the American Defense recon mounts to facilitate a quick and easy removal of your scope without a loss of zero when returned to the same slots on your upper.

On my AR I have an EOTech and Magnifier which is mounted ona larue side flip mount with a magpul BUIS that is folded down underneith my magnifier.. If the battery dies: I flip over the magnifier and my BUIS and my front sight post cowitness through the eotech.

To me this is the most adventagous set up.

I agree that this is a great all around setup. I've done similar.

Non-contributory and GD content removed - Eric802

OP either needs a carry handle mount for his scope or he needs to get a QD mount for the scope.  It's a flat top, for gosh sakes!  Get a LaRue LT-104 QD scope mount. You can pull the scope off in 5 seconds, push the button on that Magpul  BUS and use the frigging sight then.  That mount will return to zero when you are through playing with the back up sights.

Will post pics now.  Give me a minute

Ok, how do I attach a pic????  Don't see an option

This.

Also, a picture of said problem would help.

I loved the post where you screamed that it's not called a back up sight … and then edited it.

But I ALSO posted that I changed that wording.....so not like you're being a wiz detective here....wow, you have GREAT powers of observation being able to READ my post that I changed the wording.  But I still standby my post, if a BACK UP SIGHT is the ONLY sight, then its no longer a BACK UP sight, its the MAIN REAR SIGHT.  Just because someone names it a back up sight doesn't mean you have to go to your grave with that wording.  It CAN also be used as your MAIN REAR SIGHT,

I love how you have a fixed front sight post but you want a shorter rear sight.

That why I said "WHAT AM I MISSING HERE"  I have always had carry handles, first time a flatop.

I love how ever with a shorter rear sight you think you'd somehow see through your scope ring bases.

Again, that's why I am asking the questions and saying "What am I missing here".

Look, CRUMBman, you want to help, like others here are helping, fine.  You want to run your mouth with sarcasm....take a hike!!!!  What, it makes you feel SUPERIOR by making fun of other people?  Is that what gets you off?  You log off and then go beat off thinking about how superior it makes you feel to trash someone?  Others are being VERY polite, informative and helpful.  I am getting the feeling this site is LOADED with 18 year old jerk offs who love playing immature games..  This is what scares me...thinking of guys like you running around with an AR in your hands...

I can't load the pic.  Moot point anyway.  LE6920 flattop with a scope, tripod and flashlight.  But I get the point now.  

But, what I do NOT understand is if it s a flattop, without a handle, then WHY ON EARTH keep that front sight perched up sooooo high on the front sight base that comes with the carry handles???  Thats whats throwing me.  I mean chop that thing down out of the way.  If a flat top is going to be used with optics....then why not make the flatop without that front sight base sticking up to the moon to start off with?  Its just going to get in the way of the scope and make using a low profile rear sight unuasble??  Why not use a LOW profile front site, sdo it casn be used with a low profile fixed rear site, thus having the same adnatages of a carry handle in a flat top version.  The front sight base is what's throing everything off as it sticks up way too high in front?

Because people like to cowitness non magnified optics on their carbines.  Simple as that.  You can change out a gas block fairly easily to get rid of the front sight.  Personally, I left it on mine and I run either a red dot now, and will be doing a 1-6 scope soon.  The iron doesn't bother me in the least.

Wish  I could say I understood that....but I dont.

I now know the true meaning of "that guy". As a fellow newbie to the site I'd say try not to offend everybody with ridiculous backlash and listen.  To me it sounds like a QD mount would suffice if you ever needed to revert to backup sights...

And cant you still do all you say they do without that thing there?

Magnified optics can see "through" the front sight.  AR height mounts put the optic on the same plane as the rear sight.  There's really not much of a penalty for leaving the front sight on.

Cowitnessing is when you have a reflex/ red dot sight in-between your front and rear sights. With that setup you can use your sights normally and with the sight on there will be a dot on top of your front sight post. Or you can look over the sights and simply use the dot while maintaining the option of being able to use your irons if there is a failure with the optic.

"I now know the true meaning of "that guy". As a fellow newbie to the site I'd say try not to offend everybody with ridiculous backlash and listen"

Im sooooo sick of this newbie crap.  Being a newbie to a site means absolutely NOTHING.  It does NOT mesan you are a newbie to guns...  I have been buying AR's since I was 21 years old and I am 53.  Who CARES how long ive been a member?  You want to run around with your tail between your legs trying not to offend people who are TRASHING you....so be it.  I could care less.  But you need to care less about me choosing not to....

Im asking questions about sights and optics on a flat tops....doesnt mean I dont know how to use one...

Thanks, I get it now :)

Here's a pic of my setup:



What he's saying is people like their fixed front sight post and rear sight (either fixed or fold-down) to line up (called co-witnessing) with their optics.

I have a non-magnified red dot optic on my flat top upper.

If I were to run a magnified scope or a red dot magnifier, I'd have to use a folding rear sight in order to clear the scope/magnifier. If then I needed to take the scope off or flip the magnifier to the side, I could still flip up my folding rear sight and use it, as a back-up iron sight.

Yep.  See this is where it all goes over my head.  Ive been buying carrying handles AR's my whole life.  But GT Distributing http://www.gtdist.com/ProductDetail.aspx?PartNumber=COLT-LE6920  had this on sale for $895. A really good price...  but flat top.  I KNEW I would have to start re-educating myself about flat tops...I was dreading it.  Ive been simple my whole life.  I either used it with iron sites...which was fine with me.  Or I would attach a scope to the handle and I was on my way.  Simplicity.  I understand scopes and red dots.  But you will lose me when you get into advanced stuff.  Advanced to me means anything other then a red dot or a scope.  This other stuff....where there are two and three "scopes" on it just seem crazy to me.  You have magnifiers combined with....well I dont know.  Just seems like a whole lot of stuff mounted on there....

So when I got the MBUS, I THOUGHT this was an UPGRADE so to say from regular iron sights....not the ONLY set up for it.  And that is exactly where all the confusion started.  You can google some of this stuff...  but you cannot google things like what we are talking about.  That comes from experience and knowledge of others....why I am on here.

Soooo, for me, guess I am stuck with either a scope or MBUS.  Still....I just dont see why they couldnt mount an iron sight on the rear and a low profile front sight, like a bead on a shotgun, as an option.  So without having the knowledge about the stuff you guys just told me, about red dots lining up with th front sight, it all seemed stupid for me.  I mean how do you google that info???

I have been using this sight for many, many moons but never a member.  Knowing I was getting a flat top and would have some questions, I joined.  I can't say its been enjoyable.  99% of the time I am attacked with wisecracks, sarcasm and some down right assholes...  Why?  No other reason than I am asking a question that THEY know the answer to...

I AM a memeber of several other gun forums and have been for quite some time and have had absolutely no problems at all.  I was "WARNED" not to join this forum for that exact reason, that the people on here were smart asses...

But, you guys have renewed my faith in this forum.  Thank you for some really good and articulate responses.  It was a pleasure learning something from you all!!!!

Co-witnessing simply means when lining up the rear sight with the front sight, the red dot of the red dot optic is also lined up with the iron sights.

A magnifier simply magnifies the red dot of the red dot sight, effectively giving you a bit of a magnified scope. It usually is mounted so it can flip out of the way (usually to the right side), so that just the red dot optic itself can be used for closer ranges where magnification is not desired.

On my setup, if I remove my red dot optic, it would be the same sight picture as using the rear carry handle sight and front sight post.

Also, if you didn't know yet, you can purchase carry handles with the rear sight to attach to your flat top upper receiver.

Sorry if we all sounded like smart asses.  

No problem

Each setup has its own issues.  With a carry handle and scope, you are really high over bore.  With a flat top you have more options, but you still have limitations.  With red dots, you can run iron sights or magnifiers at the same time, but not both.  On the other hand, a variable power scope can do the same thing without fiddling with a magnifier, but you have to deal with parallax up close.  Most folks just put a red dot or offset iron sights for that IF the are running competition.  Otherwise, a standard rear flip up works fine.

Personally, once my scope arrives, I'll just be using a 1-6 scope with a magpul rear sight that I can pop up when needed.  With a quality scope, they can take a real beating before I need to worry about breakage.  If it does crap out, a quick throw lever later, and I'm on irons.

"Co-witnessing simply means when lining up the rear sight with the front sight, the red dot of the red dot optic is also lined up with the iron sights."


Ahhhh.  Ok, That explained it even better.  So really, its almost like using your regular iron sights, just this way is an enhanced version of it???  Brighter and easier to see iron sights so to say?  Faster to line up a target with?

1. It's called a "back up" sight because it's main purpose is to be used as a back up sight. Colt most likely started including these with their rifles because they found that the majority of their customers were removing the carry handle and using an optic anyway. So, their customers would typically have to go buy a back up sight to put under the optic, and then the carry handle would get thrown away or sold. The carry handle is an expensive piece to put on every rifle if X% of them are never being used. This way *they* get to sell the back up sight and retain some of the profit, as well as save money by not including the carry handle. They're watching their customer behavior and optimizing their business accordingly.

2. If you intend to *only* use iron sights, and are happy with the magpul, then great. Most people relying on iron sights as their only system would instead probably choose to go with a fixed sight, less moving parts, less things to break or go wrong. But with the price and availability of good optics these days, the amount of people relying on *only* iron sights who wouldn't be happy *enough* with the magpul is probably small.

3. The old "scope on top of the carry handle" option, while giving you back up iron sights that you could switch to without removing the scope, also gave you a scope that was mounted ridiculously high over the bore axis and was uncomfortable to use because of cheek weld. If you're going to use the optic 99.9% of the time, wouldn't you rather optimize your system for the optic? Or would you optimize it for the .01% chance you'll ever need to use your iron sights? Most people these days choose the former.

4. If you have a flat top receiver, and intend to keep back up sights on board, the typical setup these days is to use quick-detatch mounts, so that if you were ever in need you could quickly remove your optic and go to your back up sights. Most people these days feel this is superior. There are many in the military who aren't even using back up sights anymore because the optics we have at our disposal these days are so damn bullet proof and in many cases don't require batteries.

5. The front sight post is left there, because it's compatible with the removable carry handle and all the current rear sights on the market. It's not like someone redesigned the AR platform overnight for optics and decided on a new sight height over bore axis. That would have been suicide. If you're running a magnified optic, it doesn't get in the way. If you're running a fixed optic, you can co-witness. If you don't want it there at all, you can switch out the gas block for something else and then mount a flip up back-up front sight — or none at all.

6. All of this is personal preference. You want to mount a scope on a carry handle? Then do it. You can pick up a rear carry handle online for $20. But the most common system today of using fold down back up sights underneath great optics is working out for millions of people every day, including many of them who are putting their life on the line.

7. For 53, you're responses and personal attacks are … wow.

Getting rid of the carry handle/rear sight setup really just gives someone various and almost endless options on what kind of sight setup they'd like to run. It's all just a personal preference. What works for one may not work for another.

And that's why people love the AR platform. It really has endless possibilities as to the way the whole entire gun is built.

Faster to use, definitely.  You pretty much look at it like a lollipop.  Give me a second to find an image.

ETA:

So you'll see the red dot of the optic on top of the front sight post ala a lollipop or an i

All I am trying to achieve in reality, is to still have both as I do on my carry handle. I can either look thru my scope, or if I chose, look thru my sights.  I just think thats really important.  If Im in the woods and someones shooting at me and my scope breaks, i just want to lower my face a few inches and still be on target looking under my scope with the iron sights.  I can see thats just NOT going to be an option, huh?  Unless, I buy a gigantically high scope mount....

Well, I could just buy a carry handle..  But I want to learn which is really best. Guess its the flat top...

Guess Im really shocked that other then the 45 degree mounts for fixed sights, someone couldnt make a fortune coming out with a fixed, very low profile rear sight that stays in place and sees under the scope, with an attachment that mounted to the post base somekind of way.  Just wonder why this has never come up before, why no one else sees it as an issue?

I did learn one thing.  Always did wonder why there was such a calling for the quick disconnect scope rings....now I know