AR, front sight post or no front sight post?


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epijunkie67
January 31, 2011, 09:34 AM
I'm looking at a lot of different AR uppers and trying to decide what style to get. I want a flat top so I can put optics on it, but that's the easy part.

It seems like the vast majority of flat top uppers come with the front sight installed on the barrel. Only a few have a rail at the front sight location. My original plan was to get flip up front and rear sights and use an optic co-witnessed to those. But accepting an upper with a permanent front sight would certainly expand my selection options greatly.

Thoughts on this? Is there a reason I SHOULD get an upper with a front sight installed? Is there a reason I SHOULDN'T get an upper with a front sight installed?

What's the deal here?

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kaferhaus
January 31, 2011, 10:25 AM
I don't like the fixed front sights on flat tops. But that being said there's zero difference.

Flip ups are great if you're going into battle. None of us are going into battle with a privately owned AR. Troops are issued weapons.

If you're a iron sight shooter you should be buying a A2. They'll give you the proper sight picture and be easier to use. Flat tops are for optics mounting and that's what all my flat tops use, optics...

I shoot HP and of course that rifle is a A2 as it's a iron sights only game.

Co witness sights are okay, but what real application do you have for them?? Zombies?

My nephew is on his 4th tour of duty in the middle east and he has said he knows of only two instances when a guy with a M4 had to use backup irons. Once the guy forgot to put fresh batteries in his sight and the other guy took a RPG frag to it.

Any real chance of anything like that happening to you?

They are "cool" but I'm not into the whole mall ninja thing. I use my ARs for real world practical applications and it's saved me a bunch of cash for important stuff like good optics and ammo.

epijunkie67
January 31, 2011, 10:56 AM
Co witness sights are okay, but what real application do you have for them?? Zombies?
But but but what about when the zombie barbarian hordes start dropping out of the black helicopters and I have to retreat to my fall-out bunker? Besides, my buddies friends uncles sisters boyfriend is a recon sniper seal ranger and he said you HAVE to have them.

In seriousness though, I like the idea of back-up irons on any weapon. I'm just worried about the front sight effecting my sight picture with optics. I've scoped several of my (non AR) rifles and a few have the see through scope bases but I've never owned an AR before. This will be the first time I've gotten to scope a rifle that lets me maintain the same cheek weld position for either the iron sights or the scope.

Quentin
January 31, 2011, 10:57 AM
For my first AR build I went with a railed gas block and removable front sight. I didn't find it to be as much of an advantage as I expected, even with a scope. So with my recent build I went with a fixed FSB and am glad I did. I'd say fire a few ARs with the standard FSB and see what you think.

kaferhaus
January 31, 2011, 11:14 AM
You'll never see the FSB with a optic.... almost magic.

epijunkie67
January 31, 2011, 11:36 AM
I'd say fire a few ARs with the standard FSB and see what you think.

Spent 5 years active duty as a combat engineer back in the 80s so I've put plenty of rounds through a standard M16. I've just never used an AR with optics before.

You'll never see the FSB with a optic.... almost magic.

Even with something that sits low, like a reflex or standard red dot? I assumed that anything co-witnessed to the iron sights would put the front sight post into the sight picture of the optic.

Chris Rhines
January 31, 2011, 11:38 AM
If your "real world practical applications" include defending yourself with your AR, then backup irons are a good idea. Even very good optics can fail, or be made unusable by environmental conditions.

On my 3-gun ARs, I use 1-4x or 1-6x variable scope, and no front sight. Even through the optic, I still can see a faint shadow of a front sight tower, and I find it slightly annoying.

ETA - With non-magnifying red dot optics, you'll absolutely see the front sight post through the optic. Fact of life. The idea is, you'll be focused on the target or the dot, so the front sight will be in your perepheral vision.

-C

kaferhaus
January 31, 2011, 11:49 AM
Even with something that sits low, like a reflex or standard red dot? I assumed that anything co-witnessed to the iron sights would put the front sight post into the sight picture of the optic.

Not with a scope. With a red dot or Holo sight you WILL see it. A scope of 2x or more will make it disappear.

Al Thompson
January 31, 2011, 11:56 AM
I like the front sight for RDS as you can use it as a giant ghost ring if your sight fails. I don't have rear iron sights as my AR with an Aimpoint and FSB works just fine out to at least 75 yards.

henschman
January 31, 2011, 12:33 PM
I don't have any problem with a fixed front sight... it doesn't get in the way with any optics setup I've ever dealt with. With a red dot, it doesn't matter because the dot is above the tip of the front sight. It doesn't obsure your sight picture any more than with regular iron sight shooting.

Also, it would involve one more action to flip the front sight up if you are in a situation where you have to go from optics to irons quickly. It also seems like a railed gas block with a flip-up front sight might weigh a little more than a regular triangular gas block front sight... probably not much, though. It might just boil down to cost... it would cost extra to buy the gas block and/or the front sight to go on it, and why do that when the regular fixed front sight is good to go? It may also be just one more mechanism to break or fail. I'm all for keeping it as simple as possible.

benEzra
January 31, 2011, 01:04 PM
Co witness sights are okay, but what real application do you have for them??
Any application in which failure of the optic would be a significant inconvenience. They also allow you to instantly check the optic's zero (just drop your head to look through the irons, and make sure the dot is sitting on the tip of the front sight post).

I'm just worried about the front sight effecting my sight picture with optics. I've scoped several of my (non AR) rifles and a few have the see through scope bases but I've never owned an AR before. This will be the first time I've gotten to scope a rifle that lets me maintain the same cheek weld position for either the iron sights or the scope.
If you are using an unmagnified optic (e.g., red dot or Eotech), what's known as a "lower 1/3" cowitness (in which the irons are visible in the bottom 1/3 of the glass, rather than dead center) makes the front sight totally not a factor. In normal shooting, you're looking over the top of the front sight post, and you don't even notice it. If you have to use the irons, drop your head marginally.

If you're looking to set up your rifle with a magnified optic, though, then a folding front sight might be convenient.

CraigC
January 31, 2011, 01:12 PM
Any real chance of anything like that happening to you?
Uh, yeah! You don't have to go into battle for an optic to fail. Glass fogs, reticles break, point of impact shifts, mounts fail, etc. I even had the QD screw on a Warne ring break due to changes in temperature. Then again, I've also had a levergun get knocked over and break its Lyman 66 receiver sight. So anything can fail and it doesn't take an RPG hit for it to happen. An AR with backup flip sights is no more "mall ninja" (how about we outlaw that BS???) than a Marlin levergun with a 1-4x and its iron sights still in place. Then there are those of us who like to have, and regularly use, both. Even on the same rifle.

Not everybody's using a $500 red dot either. :rolleyes:

JQP
January 31, 2011, 03:33 PM
I am at the point where I only want to use irons, and the M16/AR style sites are gtg.

I qualified as expert just fine with irons on my A2.

I do not need the worry of breakage, batteries, bumping off zero and other such thing with a general purpose AR fitted with optics. Some will need or want optics for specific reasons, some legitimate, some crazy, but that's what makes the world go round.

AR27
January 31, 2011, 05:14 PM
Buy one with a fixed sight installed, they are perfectly mated to the barrel they come on, you cant get a better gas block. If you get tired of it just chop it off into a lo-pro with a dremel. Then you can cover it up with a rail for a reece style build or just leave it exposed. Its easier than taking a piss.

epijunkie67
January 31, 2011, 11:27 PM
I qualified as expert just fine with irons on my A2.


So did I, 20+ years ago. Unfortunately after 11 years of full time school and reaching bonafide middle age I just can't make out distance detail like I could before. So I'm realistic enough to know I need to use an optic, but I still want the option of irons if I need to fall back on them.

Tirod
February 1, 2011, 10:41 AM
Optics fail. Having a back up of some kind has been recommended since iron sights were deleted from hunting bolt guns in the '70's. Plenty of hunters find their trips compromised because of an optic that didn't survive in a badly handled gun case, or simply fell over when leaned against a truck.

Iron sights on a military weapon, even more so. Climbing through a combat hatch, negotiating narrow passages, woodland overgrowth, stuff beats on an optic.

Fixed or flip up is more budget based, the "split second it takes to deploy" is probably about as rare as having the optic glass damaged. That means, maybe, so combat guns generally use fixed. The final Improved Carbine, we'll see. For a buyer/builder, back to the budget - flip up rail mounted sights are not cheap, and even the polymer cost more than simple issue sights. Why injection molded FRN is more expensive than CNC aluminum or forged steel, I don't know, not going there. Unless it's 1/4 MOA NM, they all do about the same thing, actual performance isn't a quantum leap from bottom to top. If anything, sights get more talk about durability in rough duty, not extreme precision and significantly improved hit probability on what amounts to a 2MOA shooter for many.

Sights are what you like, and/or what you can afford. For me, an AR15 without the issue FSB triangular profile on it is just another race/space gun. Like a Garand with CAR stock, or AK with railed fore end, it's something anachronistic, a blend of different eras.

kwelz
February 1, 2011, 11:52 AM
People who rely on their weapon every day will almost always want a fixed front. In a purely defensive carbine I also prefer one. But there is nothing wrong with Flip ups.
Both my training guns have Fixed and my SPR and SBR have flip up sights. Both work well.

You never notice the flip up sights when using a RDS. If shooting both eyes open you will not focus on it and at worst it will be a small smudge in your vision. One of my Guns has a Fixed Front, Fixed rear, and a Aimpoint Micro. No problems at all there. My other has a Fixed front Flip down rear and a Micro ACOG. It also works very well.

txhoghunter
February 1, 2011, 01:42 PM
Epijunkie - I have a flat-top AR with a fixed front sight. When I am going hunting, the front sight does not even show up through the magnified scope.

However, when I'm walking around the farm (with aggressive wild dogs and hogs) I have a red dot AND a flip up rear sight just in case. When I look through the red dot I can still see the front sight post, but it does not interfere with my sight picture. If the red dot goes down, I still have the back up irons in case I need them.

Do I see this as "mall ninja"? Not at all, I have been attacked by these dogs in the past and will take the necessary precautions to protect myself for the future.

It depends on what you will use your AR for. If you will use this for home defense, I would recommend getting a fixed front sight so that if something goes wrong, you only have to flip up the rear.

JMO, yours may (and probably will) vary

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