Move AR-15 front sight further forward?

[Caliper_Mi]

I am planning to buy an AR-15 this year, trying to do some homework... Since I like shooting iron sights, one thing that has always kinda bugged me about these rifles is how far back the front sight is from the muzzle. The Russians always had the sense to put the front sight out there and lengthen the sight radius where they could.

So, would it work to replace the standard front sight / gas block with a flush gas block and add a clamp on front sight to get the front sight as far forward as possible? Even better, could a standard style front sight be pinned on just behind the muzzle?

 

[GLShooter]

Well you could use a bloop tube to extend the sight radius but that would not be practicalINMHOhttp://www.medeshafirearms.com/Extension%20Tubes.htm

You could use a front sight that had been bushed to make a tight fit on the barrel and let you move a sight tower forward.

In reality they are shooting sub-MOA groups at 600 yards with gussied up basic sights (smaller apertures and thinner blades) in HP matches ll over the US. I'm not sure how much more an extra 4" would do for your accuracy.

If you do rig one up post some pics and target results. It might be worth a shot at the mod if it really pays off in a demonstrable manner.

Greg

 

[nipprdog]

Psssst,............ Dissipator.

http://www.bushmaster.com/catalog_xm15_BCWA3S16D.asp

 

[Wahoo95]

One of the gus I shoot with has a 24" with bull barrel. He simply mounted a ralied gas block to th eend of the barrel just shortof the muzzle and mounted a front sight to it. Works great and gives a LOONNNGGG sight radius.

 

[henschman]

You think exactly like I do, BluEyes. I always wondered why rifles like the AR, FAL, G-3, Galil, etc. have all that barrel out there to put the front sight on, but they stuck it back at the gas block. Is it to save some miniscule amount of weight? Did the designers just think it looked cooler that way?

The proper way to set up iron sights is not too hard to figure out... longer sight radius allows for more precise aiming and has no downsides. So the rear sight should be at the back of the receiver, and the front sight should be at the tip of the barrel. As far as self-loading rifles go, it seems like John Garand was the only one who had the right idea. Eugene Stoner put the rear sight in the right place but screwed the pooch on the front sight. Mikhail Kalashnikov put the front sight in the right place, but totally flubbed the rear sight.

There is a version of the AR called the "dissipator," which does what you describe. It has a low-profile gas block that goes under the handguard, and it has a regular gas block front sight (with the gas block obviously inactive) mounted out at the tip of the 16" barrel. It uses rifle-length handguards.

You can construct such a setup yourself, using any type of gas block front sight base you want... railed, folding, or factory fixed. This will make your sights move less MOA per click, but this isn't a big deal since the MOA values are AFU on anything with the square post front sight or the carbine-length sight radius anyway. I would go with a free float tube instead of the factory type handguards, too.

Some guys get longer sight radius on an AR by using a really long free float tube that reaches nearly to the muzzle, and putting the front sight on the tube. I don't like this method, though... the handguard moves with any kind of pressure, like using a sling or resting it on a surface. For the best consistency and precision, the FS should be attached to the barrel (and the rear sight should be attached to the receiver).

Maybe this is fine if you just consider your iron sights to be "backup," but I am kind of Jeff Cooper-esque in my belief that you should always be prepared to use your iron sights as your PRIMARY sighting system if necessary.

 

[Onmilo]

You can place a front sight anywhere on the barrel as long as the diameter of the barrel is the same as the inside diameter of the front sight block.

You must also use a seperate gas block located at the correct point to ensure reliable function.
The correct point being the original location on the barrel, whatever and wherever that might be.

 

[Caliper_Mi]

Wow, thanks for the excellent responses guys! Glad that the solution already exists instead of being totally custom. I'll be putting a dissipator on my list...

 

[langloisandy]

Blu,

I run a rifle free float rail on my carbine with sights bolted to it ( magpul ) this gets my sights forward of the normal positioning and longer radius.

Andy

 

[kwelz]

You could run a Mid length gas system whcih will get you a couple more inches of sight radius.

You could get a Dissipator, although I would wait for BCMs offering and skip Bushmaster.

Or you could run a Free Float tube and put a nice troy BUIS on there.


I suggest either option 1 or 3.

 

[Tirod]

This won't really be any help at all feeding the EBRD: http://www.ar15.com/forums/topic.html?b=3&f=118&t=509821&page=1

The hardest part of the build is fitting the front sight base. I'm converting a .625 pencil barrel FSB by honing it to .700 to fit a barrel. The tools are not generally sold at AR suppliers, and it will also need to be cross drilled, and either tapped for fasteners or pinned. I'm also planning to split it for more clamping pressure.

The JP adjustable would just about cover the tools I've been buying and would already be done, much less look hi-speed. http://www.bravocompanyusa.com/JP-Adjustable-Gas-Block-Front-Sight-Base-p/jpgs-2fs.htm

Nobody has actually done the math on moving the sight forward 6" and figuring the increase in accuracy, we all just say it works. On a combat firearm, 2MOA is standard, and the existing sight radius and ammo deliver. It's not a high precision game, and up until low pro gas blocks became common, using rifle gas on a 16", or having gas tapped that close to the muzzle on any AR would cause cycling problems galore.

I'm doing it not because of sight radius, since it will get an optic, but because longer handguards are easier to shoot with the arm extended, and it protects the user and barrel more. It's a hunting rifle, no tight sling needed, so a rail was unnecessary. I spent the difference on a better barrel.

 

[Quentin]

I also recommend a midlength gas system if you're going with a 16 or 14.5" barrel. If you're going with an 18" barrel then you could use the rifle length gas system. Both of these gas system lengths give you a longer sight radius than the carbine length under the Dissipator handguards.

And if you want rails intead, well you can go with a low profile gas block and 12" rails then put your front sight almost at the muzzle.

 

[WoodyTX]

After a certain point, I would say that the increase in sight radius simply isn't worth it. Where that 'certain point' lies, is conjecture, but a good place to start would be the accuracy between the M4 (14.5" sight radius) and the M16 (19" sight radius).

Nearly a decade has passed between my carrying an M16 and owning an M4gery, so I can't really speak to this. Anyone else have some real-world info?

 

[TonyAngel]

Blueyes, have you thought about just buying a rifle? Other than that, the easiest thing to me seems to be to get something like a Yankee Hill clamp on gas block/fsb. Then, all you'll need to do is turn a ring to act as a spacer. No drilling, tapping or pinning.

Like the ones shown on this page....http://www.yankeehillmachine.com/store/sights.html

 

[Caliper_Mi]

If I bought a rifle barrel, I'd still want to move the front sight forward on that, too

Did some math, going from 14.5 to 19 is a 24% increase in sight radius. Or, in other terms it is a 24% decrease in the apparent size of the front sight on the target and a 24% increase in the apparent movement of the front sight for any aiming error by the shooter. Liking it, that should be a noticeable difference!

I think I will stick with barrel mounted sights though. I won't be buying a very fancy handguard so I am sure it will deflect some from sling pressure, etc.