AR scope question

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quartermaster

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I put a 3-9 x 40 scope on my AR last night on top of a 3/4" riser. I have a fixed front sight that is non removable unless I do something else with the qas block.

I am able to see around the sight with no problem. My question is, am I seeing a false image or the actual point of impact? If my rifle and myself are capable of being very accurate, am I barking at the moon trying to shoot tiny groups?

I haven't sighted it in yet, but wondering what I am up against.

Thanks in advance, QM
 
If you can see the crosshairs on the target through the "shadow" of the front sight, you should be fine.
 
If the FSB is LOWER than the center of the reticle, it won't be much of a problem. If the frontsight is blocking the crosshairs, even if it only appears as a shadow in the scope, you will drive yourself crazy trying to make precise shots. You will have the illusion of the reticle being on the target but there is no magic letting you see through a solid object. I went through this experience mounting a high power variable on an AR with an FSB. At close range where a precise hit wasn't needed it, the problem was barely noticeable. But as soon as I tried aiming for a precise location, it was like having a blind spot that you couldn't see. For a precision AR, it's best to not have a front sight blocking your field of view
 
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As the others above have stated, it will only be a distraction that you can ignore, but if it really really bugs you, one option is to replace your front sight with one that folds down. Here's one example of a fold-down front sight.
http://www.midwayusa.com/product/34...4-style-ar-15-handguard-height-aluminum-black

Be aware that some cheaper sights are made of plastic. They are still OK, but you should not use a plastic sight on top of your gas block, which might get too hot for the plastic. I do have plastic on one of my AR's, but they're on 45degree angled mounts, so not directly over the hot spot.
 
It is mind over matter. If you don't mind, it don't matter. You will likely only see it at the lowest magnifications. When shooting at anything above 5X or so it will disappear.

I've never understood the complaint. You see the front sight, and it obstructs just as much of the view when shooting with irons as with a scope on low magnification.
 
Many shooters say it's no big deal, but few understand what the real problem is. It's one of those internet memes people accept but never stop to think through.

Physics and science shows it's more than just a distraction. When the front sight blocks the reticle, the shooter cannot place it directly on the target. Because the front sight is greyed out and doesn't appear solid, the brain is tricked into thinking the eye can see the target. While the front sight appears to be just a shadow, the reality is, it physically blocks the reticle. It blocks a spot on the target creating a blind spot that you cannot see and within that blind spot, you cannot make a fine aim. It will open your groups and give you eye strain.

As I said earlier, I had a scope mounted on an AR at a height that the front sight was higher than the center of the cross hair. My groups opened up, I couldn't get the rifle properly sighted in and there was increased eye strain. When hunting, I couldn't place the crosshairs precisely where I wanted them. At first, I thought it was a problem with the optic but it happened no matter which scope I tried. Since I ditched the front sight, all the problems went away.

If you mount the scope so it's the height would offer a 1/3 lower co-witness, there shouldn't be much trouble. But if the front sight blocks the center, you'll notice a difficulty making precise shots.

QM, is the scope mounted low enough that the center of the reticle would be blocked by the front sight?
 
A buddy of mine recently put a scope on his and you can not see his front sight.
Try looking into a scope designed for the AR platform.
I dont know what make it is.
 
What will a scope "designed for an AR" give you that a standard scope will not?
 
The scope is a 3-9 x 40 vx3. I can't see how possibly I could shoot accurately at either short or long range, but I am hoping I will be able to. The objective of the scope is only about an inch behind the front sight and the sight post goes up 2/3 of the way towards the top of the objective. It baffles me that I cam even see around it. I figure there must be a lot of light refraction which allows me to do it. That being said, I think I will be disappointed
 
Robert,

Here you go. Looking through the scope at short or relatively long range, at low or high magnification, I see no sign of the front sight at all. As a matter of fact, everything is very clear. I can't move the scope back as eye relief is perfect. I guess the only way I will find out is to shoot it and it's too cold here now to play
 

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Yep, that's gonna drive you crazy. Having the mount attached to the receiver and handguard could also give you problems. Shooters in the past have found mounting their optics that way gave them a wandering zero. Some have found it to be no trouble at all.

If that optic is going to be permanently mounted to that rifle, I'd cut the FSB down
 
If it fouls you up and you like the optic and optic location you might consider cutting the front sight base down.
 
I feel kind of stupid when it comes to ARs, as I really don't know much about them. Rifles, pistols and reloading, yes, but I need to get the book ARs for dummies.

Mistwolf, I can understand a chance of a wandering zero, but where else could I mount the scope or what other options do I have? I am hoping that the riser will add some stability to the mount. Welding Rod as well, I can't see cobbling up a perfectly good rifle by cutting off the front sight, although I see both of your points.

I am considering getting a different upper with a beefier barrel and no front sight, but looking at them online, I am seeing different size gas ports which I don't understand either. That way I could have an optic for hunting and target shooting and open sights if the SHTF ever in my lifetime. I'm assuming that the gas port size is important?

I bought this model (Stag Arms Model 2T), as I thought it was one of the better ones at the time and read good reviews on it's accuracy.

Possibly my concerns will go by the wayside when I shoot it, but I can't believe that I am seeing a real view of my aiming point. It also baffles me how clear of a picture that I see looking through the scope.
 
Count me as one who doesn't seem to have a problem. I admit its nice to have a clean field of view, and if it really bothered me I would install a gas block with fold down post. BTW, I do have such a set-up on my Stag Arms 3H...

M
 
There are many different front gas blocks. A number of companies have fold down front sites in their gas block

http://www.armsmounts.com/default.asp?mode=products&sub=sights

http://yhm.net/index.php?main_page=index&cPath=6

You could put a gas block with a rail on the top and then you can put anybody’s fold down front site.

http://yhm.net/index.php?main_page=product_info&cPath=2_6&products_id=37

I just grabbed two companies for examples, there are more.
If the front site is problem, change it. That is what is so great about the AR platform, it is modular, you can change whatever you want on it.
 
Totally the wrong scope for that rifle.
Click to expand...
Thanks for the help that is some great advice. :rolleyes:

Ok now I am tracking. Take that rear sight off and move your scope back, or another option is go to a different optic. A different upper may not be a bad idea either. You can get something a bit bigger like a 6.8 for hunting. If it is a complete upper then push the two pins, pop the old one off and pop the new one on. Keep the shorter upper and put a nice red dot or low power optic on it and have the best of both worlds.
 
I like RMC51's idea, but don't have a clue about how to do it or the expense involved to have it done. Can someone shed a little light on this subject. It looks to me like the sight is fastened to the barrel somehow.

I don't want to get a scope with lower magnification, nor a red dot. I need the magnification due to aging eyes. I am looking for accuracy and red dots are too big for me with the exception of the EO Techs, which I don't care for because of the battery life and dependency.

As far as getting another caliber, out of the question. If I wanted that, I would have got it when I bought it.

I can't move the scope back due to eye relief.

I guess I will just try it and see what happens. If it doesn't work I will try to go the RMC51 route
 
Go over to ar15.com and learn more about the ar than you ever want to know. Also try M4carbine.net. Both these sites are very instructive . just go to their tech discussion threads and you can learn a lot about the AR platform.
 
chris in va said:
Totally the wrong scope for that rifle.
Click to expand...

Not if it matches the mission. A 16" AR carbine will shoot almost as far as a 20" AR with as much accuracy.

A lot of shooters have tried bridging the receiver & top rail when mounting an optic and have had poor results. I've talked to a few who have had no problems at all. Of the ones I've talked to, the ones with problems out number those who have not. Yu could get lucky but I think ammo is too expensive to take the chance.

QM, the simplest solution to your dilemma is to get a cantilever mount. Aero Precision makes one that's tough, very light and at $85, you can't beat the price. If I hadn't gotten a KAC mount at a real good price, I would have gone with the Aero Precision
Scope-Mount_Left_B.jpg

http://aeroprecisionusa.com/shop/ultralight-30mm-scope-mount

There are others that will work, but for the price and what you're getting, the AP mount is worth a serious look. Once you do get a cantilever mount, it may mount the scope high enough to clear the FSB. But if you need a scope for your eyesight, I suggest you just cut yours down and don't worry about BUIS. Then shoot what you have before making any other changes changes or getting another upper. No sense in spending money you don't have to.

Don't feel stupid. You're asking questions, listening, sorting through the answers and learning
 
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