AR flip up sight options Q

[Walkalong]

If one is going to use flip up sights on an AR, is it better to have a flip up sight on a railed gas block or on the railed free float tube and why. YHM makes them either way, and I suppose others do as well.

Should I use a railed gas block with a flip up sight mounted on it with a Carbine length free float tube, or use a Mid-length or Specter length free float tube and mount the front flip sight on it?

How does that affect optics height? Does it not matter?

I would like the flip up sights to be dead center of an older Aimpoint "5000 Mag Dot" sight when flipped up, and out of sight when flipped down.

Is either mounting option better for accuracy? Are both "good enough" for combat accuracy?

Any insight will be appreciated. Thanks, AC

 

[rcmodel]

It would seem to me the gas block mounted sight would be much more likely to retain it's zero as the barrel heated up and moved.

Unlike the handguard mounted one, at least the front sight would have to go with the barrel!

I couldn't prove it though.

If you shoot with a sling attached to the handguard, a gas-block mount would not be effected by sling tension.

rcmodel

 

[Walkalong]

Good points, and points I have pondered as well. Though I would ask the pros.

 

[schildgen]

Then

 

[Walkalong]

No longer applicable since schildgen's edit

 

[AK103K]

I have GG&G BUIS on one of my Armalites. The front sight is mounted on the gas block and zero has never been an issue. Mounted on both flat tops gives perfect alignment with my Aimpoint.


The sights are down in this pick, but you get the idea.....

 

[Guitargod1985]

I 'm going against the grain here, I guess. I actually prefer the back up iron sights on the free float rail rather than the gas block. This allows for the use of a low profile gas block, which can go underneath a longer rail system. If you have a flip up sight in the way, the are confined to a rail system that fits behind your gas block.

 

[JWarren]

I agree that it may be better to have front sight connected to the barrel via the gas block.

However, I am an optics guy. I figure that irons attached to the forearm are fine for the level of accuracy that I'd use iron sights for. After a certain range, I am looking to use optics.

I prefered to go with a "specter" profile barrel by using a 16" M4 barrel and Rifle-length forearm. To me, the aesthetics of the rifle are improved as I do not like the long skinny barrel sticking out on a carbine. However, aesthetics is not a prime focus. I like having more of the barrel shrouded and the additionl rail length. This allows for mounting something like a bipod further towards the muzzle.


Here's mine sans any optics. (deciding on the right one.)


-- John

 

[MassMark]

YHM makes some decent stuff, but my opinion for whatever it's worth on the Internet, is that their sights do not hold a candle to Troy BUIS....

 

[VARifleman]

YHM folding sights wiggle a lot. I would consider other brands.

 

[JWarren]

YHM folding sights wiggle a lot. I would consider other brands.

The rifle I posted has YHM sights.

I feel that some clarification should be made to the above quote.

The YHM sights DO have a small amount of "play" in them. However, the play is in a forward/rearward movement, not a side to side. The sight bases lock firmly onto the rails-- the play is in the mechanism itself.

From my experience, the play is not so loose that they will "flop." And it is not so extreme that I think it would affect accuracy to any great degree.

Are there better flip up sights out there? Most definately. However, YHM provide a VERY affordable alternative to us. I got my set for the price many pay for one sight. I don't feel handicapped by them, but recognize that I could have gotten a tighter one.

As I see them, they have been as accurate as I need Irons to be at the ranges that I shoot Irons. The savings go towards an Aimpoint or EOTech.


-- John

 

[halfacop]

I am wondering if you have any issues with that specific vertical grip on that YH rail?

I have that same VFG and gave it to my buddy - but he has a YH Carbine rail and the grip does not tighten down enough and will slide the lenght of the rail due to the rail slots not being machined all the way across.

Any issues or if so what did you do to over come them?

 

[MassMark]

I'm not sure how $90.00 for a rear sight with "play" and $140.00 for a rear sight with no play translates into a good deal...I'm not being critical, if wiggle room in a battle sight is okay with you, them so be it. It's not okay with me, so I found room in the budget for a sight that is built like a tank - I bought a Troy....

 

[MaterDei]

AK103K and JWarren, those are nice rifles. Thanks for the pictures.

I was going to say that mounting to the gas block as opposed to mounting on the hand guards would also give you a longer sight radius. But then I saw John's set up.

 

[Walkalong]

I don't want junk, but I am not looking for the absolute best stuff. They are back up sights. They need to be accurate enough for close quarters defense if the optics fail.

As far as a free float rail, I want a pretty good rail. I bet the $250/$300 rails are sweet, but I don't need one that good. I just want one that is sturdy and reasonably well machined. It does not need to be absolutely perfect.

Looking forward to more opinions.

Oh and define BUIS.... please. Thanks

 

[Organdonor]

Keep an eye on the AR15.com equipment exchange. I got a used MI front gas-block mounted BUIS there for $40, and TWO Wilson Combat rear BUIS for $100, shipped. All are rock solid.

Oh, and I agree, the longer FF rail system with the front BUIS mount on it look SWEET... I like it when the low profile gas block is covered completely by the front railed foregrip.

 

[modifiedbrowning]

Oh and define BUIS.... please. Thanks

BUIS= Back Up Iron Sight.

 

[Walkalong]

Duh, thanks.

 

[VARifleman]

The YHM sights DO have a small amount of "play" in them. However, the play is in a forward/rearward movement, not a side to side. The sight bases lock firmly onto the rails-- the play is in the mechanism itself.

This is correct in that there was no apparent side to side motion in the sights, but front to back affects elevation, sometimes by a lot.

 

[Zach S]

Mine is simular to JWarren's, although mine is a factory built dissipator style rifle, so I already had an FSB in the rifle location. Although I dont really care about asthetics or additional rail length (I just have a VFG and light mounted), I just prefer the longer A2 sight radius over the CAR.

If I had a CAR, I would install a rifle length FF forend and use a rail mounted sight. This way I wont have to worry about installing a gas block or FSB on the bbl. I prefer fixed sights but that's another thread.

 

[JWarren]

I am wondering if you have any issues with that specific vertical grip on that YH rail?

I have that same VFG and gave it to my buddy - but he has a YH Carbine rail and the grip does not tighten down enough and will slide the lenght of the rail due to the rail slots not being machined all the way across.

AFTER I got that Falcon VFG, I discovered that the Falcon VFG does not lock tight on some rail systems. Much to my chagrin, I discovered that YHM IS one of those. My grip failed to lock up tight.

It locks solid now. Before I sent it back, I decided to take a look at what the problem is. The issue is that there is a Post in the center that screws up to lock on the rail. It would not screw up high enough to lock down.

I decided to get a piece of spare metal I had laying around. I shaped it to fit into my Rail slot with a dremel. After getting it to line in perfectly and tightly, I then drilled a "Dimple" in the center of the metal I crafted.

Once I screwed the post into the new adapter and into the dimple, it locks as solid as I had hoped.

It really wasn't a hard process, and I am satisfied that it will last through anything.

I hope that helps.

I was going to say that mounting to the gas block as opposed to mounting on the hand guards would also give you a longer sight radius. But then I saw John's set up.

Hehe... yep... I basically created my own "Dissipator" profile. It was part of my equation to create a longer sight radius.

This is correct in that there was no apparent side to side motion in the sights, but front to back affects elevation, sometimes by a lot.

I concure that any front-to-back motion would affect elevation-- sometimes by a lot.

However, that would only be if they were prone to move. The only play that mine exhibit is if I manually move them with my finger. I can't make them move with movement or jarring of the firearm.

However, I DO agree that if you desire significant range and accuracy out of your irons, you REALLY should look to a more expensive one. Hell, you may want to consider fixed detachable ones rather than flip ones to be sure.

For me, they are plenty accurate for the ranges and accuracy that I got them for. I truly do see them as BACK-UP. Soon, I'll have optics on mine.


Just my 2 cents.





-- John