flip up vs fixed

[wolf10851]

ok I did a little searching but couldn't find any threads on this. (I probably missed them knowing me) but here is my question. I am building an m4 clone and I am stuck on 1 issue. the front sight. once I get the upper I do not plan to change it so I want to get the right one from the beginning. I know I am going to get a flat top upper and a detachable carry handle. I may sight through the carry handle or I may mount some kind of optic on it. or I may just mount the optic to the flat top of the rifle. but those are all options I can deal with later. my issue is the front sight. which is better a flip up front or a fixed front? with a flip up front is it tall enough to sight the rifle with the carry handle sights? with a fixed front sight does it get in the way of a holographic sight if it is mounted directly to top of the rifle?

I am looking for pro's and con's to either option so I can know which would be a better way to go
Thanks

[Norcal Industries]

personally, i like to run rifle length rails and then use simple magpul mbus' flip-ups. that way i can throw optics on and retain my irons (plastic) if i need to. the fixed front sight works if you use optics with magnification, but kinda gets in the way if you use lower magnification (3x or less).

[bubbapug1]

I think if the iron sights ae back up I would make them flip up. Use high quality ones that will provide repeatable results.

[GeoffLinder]

Get an upper with rail milled into the top of the gas block and then you can put any type of front sight you want there or nothing at all

Clamp on front sights are available in fixed or folding style and with many options of post or reticle and hooded or ears, etc...

[wolf10851]

so if I go with a railed gas block and a flip up sight is it the same height as a fixed sight?......when flipped up of course

[Omega13device]

If you're getting a railed handguard don't bother with a railed gas block because you can mount either a flip-up sight or a fixed sight to the rail (see below). That gives you the flexibility to experiment.

LMT rail-mounted fixed front sight: http://www.riflegear.com/p-629-lmt-t...-assembly.aspx


As to which way to go, it doesn't really matter. It's mostly a question of personal preference. If you end up going with an optic, there are separate optic mounts that place the sightline of the backup sights either in the center or the lower 1/3 of the optic window.

[GeoffLinder]

If you're getting a railed handguard don't bother with a railed gas block because you can mount either a flip-up sight or a fixed sight to the rail (see below). That gives you the flexibility to experiment.

LMT rail-mounted fixed front sight: http://www.riflegear.com/p-629-lmt-t...-assembly.aspx


As to which way to go, it doesn't really matter. It's mostly a question of personal preference. If you end up going with an optic, there are separate optic mounts that place the sightline of the backup sights either in the center or the lower 1/3 of the optic window.

Yes BUT, you are now sacrificing sight radius and that will make it a good bit harder to do any accurate shooting with them. Sight radius is what makes a rifle with iron sights much more accurate than a pistol with iron sights.

Get the railed gas block and you won't be sorry when you try to use them for anything but point blank to typical rock throwing distance. Sight radius is a very big thing IMHO.

As far as height of front sight goes, you need to make sure you get parts that fit each other on YOUR rifle.

The rifle needs to have it's barrel at a slight up angle compared to the line of sight through the sights. Both of these sight lines need to converge at about 40 yards.

To do it by measurement you need to measure height above bore centerline to center of rear sight aperture. The top of a front sight post needs to be just barely below this height (in the middle of it's adjustment range) for you to be able to sight the rifle in. You can calculate this height difference by dividing 1440 (how many inches in 40 yards) by the distance between the sights in inches. Then divide the height of the rear aperture above bore center by that result and you will have the distance in inches the top of the front sight needs to be below the center of the rear aperture.

Based on a sight radius of 14" and a rear aperture height above bore of 2.5" this would tell you the top of the front sight needs to be .025" below the center of the rear aperture to get a 40 yard zero going.

Another way to get it set right is to remove upper, pull bolt carrier, align it in a vise or on sandbags so an aiming point at 30-40 yards is visible looking through the barrel. The front sight is the right height when you see the same aiming point through the sights as you do through the barrel.

[Mac Attack]

Its funny how peoples opinions on flipup sites have changed in the last 5-10 years. When I asked the same question the OP asked on AR15.com 10 years ago I was given a resounding answer to stick with a fixed front. I went with a flipup anyways and have run the same one ever since. Now a days the norm is to go with a flip over a fixed. Go with the norm and you will be happy with it.

I wouldn't waste my money on a removable handle if you plan to add optics. Better to spend your money towards a good site or more ammo.

[GeoffLinder]

If you want a rugged-azz rifle to take into the shjt with ya, there is nothing better than an A2 style carry handle with protected rear peep and standard style front post with protective ears. It takes a lickin' and keeps on tickin' and with some practice scope level accuracy to 300+ meters is not a problem.

Clamp-on carry handle adapter on a flat-top with one-piece non-folding A2 style front sight clamped on railed gas block up front is just as capable of being used as a club AND a rifle without losing your sights as an A2 iron-sighted stocker is.

If the need for some defensive rifelery were to ever appear, my fancy rifles with optics and red-dots stay in the safe and the box-stock A2 comes out

[uxo2]

https://danieldefense.com/components-parts/upper-half/sights/fixed-front-rear-sight-combo.html

I pefer fixed...always have

[GeoffLinder]

https://danieldefense.com/components...ght-combo.html


I pefer fixed...always have

+1, nothing moves, nothing breaks

BTW, That's a quality set of clamp-on's.

If the rail is to spec and the sights fit without much slop I have found that removing and replacing them restores zero well enuff to get on with it.

Flip-up's are a useable backup I guess, but my feeling is one hard hit and they are probably TU so if your main sights are already out of it, then you must be in some ruff-stuff already and you are probably better off with rattle-battle gear than with razzle-dazzle gear.

The only reason I prefer the clamp-on A2 carry handle for irons on a flattop is because it "is" a carry handle AND it's just a bit better protected from hard knocks than the smaller sight only clamp-ons are.

My favorite quick action setup on a flat-top so far has been a one-piece clamp-on front and rear with a co-witnessed red-dot like a C-More or OKO at 4MOA size. Both always there, same cheek weld, no interference in the sight picture and choice of quick and quicker on your sight picture

[Omega13device]

Yes BUT, you are now sacrificing sight radius and that will make it a good bit harder to do any accurate shooting with them. Sight radius is what makes a rifle with iron sights much more accurate than a pistol with iron sights.

An inch or two or sight radius is not likely to make a measurable difference. If it did we'd all be using 20" barrels. In any case it's a secondary consideration since most people use an optic anyway, and sight radius is irrelevant with an optic.

[sevensix2x51]

i prefer the fixed front sight. ive had them both ways, and the standard front is just the most reliable/stout. anything with moving parts is going to have a weak point.

for the rear, i like fixed as well. i have the daniel defense rear fixed sight and its awesome. but i dont run optics. if the rifle uses an optic, a folding rear is a viable solution, so the sight picture is not impeded too badly. that, or lower 1/3 cowitness for a red dot. i think if i do happen upon a T1, ill run my fixed sights anyways, and just put the dot a bit higher... still havent decided whether to drop the funds into something like that, when my irons are pretty fast and always reliable..

this is all totally opinion, and its really up to the individual to find out what they like best.

[GeoffLinder]

An inch or two or sight radius is not likely to make a measurable difference. If it did we'd all be using 20" barrels. In any case it's a secondary consideration since most people use an optic anyway, and sight radius is irrelevant with an optic.

I seriously beg to differ. The difference in sight radius from a 20 to a 16er is only a few inches but that makes a very noticeable difference in potential (read easily achieved here) accuracy at any distance beyond 50 yards. Try shooting a shorty with standard irons at a 10" steel plate at 200 yards

I put a clamp-on block just behind the muzzle brake on a 20" bbl AR to get a few more inches sight radius and that change was way more than noticeable in accuracy and the ease of achieving it at out to 300 yards.

I have fired 16'ers owned by others with a front sight mounted at the far end of the main rail on the handguard and believe me, that reduction in sight radius makes them much more difficult to make pin-point hits (3-4" target size) with at anything beyond typical pistol ranges (30-40 yards).

But then again, most folks can't hit 3-4" targets with pistols at 30-40 yards anyway

[wolf10851]

thanks for all the input! I ende3d up going traditionalist m4 with a fixed front sight