AR-15 fixed front sight with scope sight picture.

Thread starter #1
I am going to buying my first AR here in the weeks to come and need some basic information.

I am wanting a carbine length rifle and gas system. Flat top receiver, heavy barrel, fixed stock and GI style front sight block/ post or whatever you call it.

My main question is what type of sight picture do you have with the front GI style sight post and a 3-9x40 scope mounted in one of the quick disconnected raised mounts?

Does the front sight post obstruct the view of the scope?

If anyone has any pics looking threw their scope with a front fixed GI post type sight please share them with me.
You most likely will not see the sight post, even on 3x zoom. There are some mounts that set the scope high enough to clear Magpul MBUS rear sights (folded down of course).

If you have the option, stop by your LGS and see what they can set you up with. ARs are Lego guns... if you dont like your set up change it!

Just out of curiosity, what AR are you looking at getting?
Thread starter #4
country boy sports in banks county has their manufacturing license and produce ar-15s. I have bought a few guns from them and like the guys up their. They have reasonable prices and a Life time guarantee. If the weapon malfunctions or has any problems I drive 15 min to their gun store and they fix it right in front of me.

They will also let you tell them how you want your AR set up. I am sure when you read how I wanted my AR set up it seamed a bit odd. But they let you build it how ever you like.

I want a 16" heavy barrel, Fixed front sight, A3 receiver, 2 stage trigger, removable carry handle and A1 fixed stock. I will be mainly using this gun for hunting. But I do shoot IDPA and over at skip J range in South Carolina and they have a pistol/rifle competition every month so I want the capability to take off the scope throw on the iron sights and shoot in their competition. Also I like the idea of having the iron sights for a home defense gun that me or my wife can use. The 12 ga is just too much for her.

Thanks guys for the information. If anyone has a photo of the scope/fixed front iron sight picture please share.


Senior Member
I'm sorry I don't have a pic with a fixed FSB because I currently run folding front and rear sights on my AR's, but I've owned guns in the configuration you're talking about and the fact is you will see what looks like a slight shadow of the fsb in the bottom of your field of view with the scope set on 3 up to 4 power (depends on the scope because the actual level of magnification varies slightly with manufacturer, in other words, 3x may actually be 2.5). Beyond 4x on every scope I've used, though, you won't see the FSB anymore. Even if you do see it, it doesn't impair your ability to use the scope. It may just be a slight annoyance.

You used the phrase "take off the scope throw on the iron sights" and if you truly intend to remove the irons to use the scope, might I suggest you not do that. Instead, use a folding rear sight that will fit under the scope when mounted. That way, you don't have to re-zero your irons every time you put them back on. I did that for a while when I first started with AR's by swapping between a scope and a carry handle. I didn't figure the shift could be that big, but even @ 50 yds there was a noticeable shift in POI.
Thread starter #6
thanks ash. I figured that the poi on the carry handle would stay about the same no matter how many times you would take off the iron sights.

Also ash556 did you notice any change in zero on your scope when taking the scope on and off?

In all reality I will only be swapping the sights a few times a year. I would probably place the iron rear sight on after deer season and put the scope on before deer season. Checking for maintained zeros on both.

Do you have any suggestions on quality folding rear sights? A friend of mine has the magpul plastic sights and what little I shot with his Ar I just did not like them.


Senior Member
I use a LaRue LT104 QD scope mount with a 2 X 7 and it holds zero well enough for deer hunting.


Senior Member
The carry handle was close, but not really precise (shift of an inch or two of POI @ 50yds).

Regarding scope POI shift, it depends on which mount you use. With a Larue, ADM, or Boboro 1pc mount, you'll likely not see any shift. With QR rings, you will probably see some. How much depends on which rings you use. I had the best luck with Warne and also made sure to put forward pressure on the scope when tightening the rings so they wouldn't move under recoil.

As far as as quality folding rear sight, there are several and quite the price range as well. I have Matechs on both of mine, but I readily acknowledge they're not the best choice. Of course, mine are truly backups as I have an Aimpoint T-1 on one rifle and an ACOG on the other. Neither of those sights are ever likely to fail, so I'm not too worried about it and I got the Matechs for free. It's not that they're really bad, but over time flipping the aperature up and down, the detent that holds it down has a tendency to wear. My recommendation would be Troy or Knights Armament. I've used them both in the past and both are very high quality. The proper height for a scope mount on an AR15 is 1.4-1.5" from the top of the rail to the centerline of the scope. When using a ring/riser combo or 1pc mount of proper height, any of the three rear sights I mentioned will fit under the scope. For instance, here's my long-range plinking setup on my 16" gun using YHM 0.5" riser blocks, Warne High rings, and a Zeiss Conquest 3-9x40:

If they are going to build you a rifle consider getting a mid-length gas system. They cycle much smoother.

ASH is correct: whatever mounts you use you will need to push forward to eliminate the shifting under recoil.