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Are all AR15 front sight towers

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S.B.
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Are all AR15 front sight towers

#1 Post by S.B. » Wed Dec 06, 2017 6:58 pm

the same even clones? The direction the pins come out? I know barrels are different diameter but, I'm more concerned about the sight bases.
Steve

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Re: Are all AR15 front sight towers

#2 Post by shoot4fun » Wed Dec 06, 2017 8:49 pm

I don't know what you are asking. Are the front sight blocks all the same? No. There are many different varieties. A1 and A2 varieties, with and without bayonet lugs, low mounts with and without a rail to mount a front sight, flip up front sights, etc. As you mentioned, they do come sized for different barrel diameters, most common are 0.625" and 0.750". Some mount via a clamping mechanism, some mount with set screws, some with pins.
The pins are directional. Most often pins are driven out to the right of the gun (holding it as if you were shooting it) and driven back in from the right to the left.
Brownells even makes a $40 bench block to help.

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Re: Are all AR15 front sight towers

#3 Post by RWS » Thu Dec 07, 2017 6:17 am

I think Steve is asking about the front sight base, not a front sight block. Just need him to clarify that point. I'm thinking he's talking about the image below. Yes or no, Steve?
p_080001248_1.jpg
p_080001248_1.jpg (18.68 KiB) Viewed 112 times
If the above is what is being asked about then as far as I know all the "Standard" front sight bases have the same height, but are available for 5/8" or 3/4" barrel diameters as Shoot4fun notes. Some are cast and some are forged, which is also a difference.

Some non-standard heights do exist, but the "Standard" sight bases as seen on USGI M-16's are all the same height as far as I know. The only height variation that I have ever seen on standard FSB's has to do with slightly different heights of the protective sight "ears".

Shoot4fun is also correct about the tapered pins. They are installed from right to left as viewed on the rifle from a firing stance.

-Bob

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Re: Are all AR15 front sight towers

#4 Post by DaleH » Thu Dec 07, 2017 8:07 am

Even pins back to an original 1600s era matchlock I have were built with the same right-to-left install orientation.

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Re: Are all AR15 front sight towers

#5 Post by Cattus Borealis » Thu Dec 07, 2017 8:46 am

The M-4 Carbine has a taller Front Sight Base. Typically they are marked with an "F

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Re: Are all AR15 front sight towers

#6 Post by S.B. » Sun Dec 10, 2017 10:34 am

I must have something wrong in my preferences? I haven't received any notices of replies? Yes, Bob, that is what I asked about.
Cattus Borealis, I just put a Colt 16" barrel on one of my ARs and can't find such a mark anywhere on the factory sight tower???
My original question was about the orientation of the taper pins and if they all come out the same way?
Sorry for any confusion I've caused.
Steve

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Re: Are all AR15 front sight towers

#7 Post by RWS » Sun Dec 10, 2017 11:08 am

Steve:

The whole point of asking questions is to clear up confusion, isn't it? A question should not be a problem for anyone.

Cattus Borealus may be absolutely correct about newer carbines having taller front sights, but all 3 of my carbines have front sight bases that are exactly the same height as the standard M16 front sight base, and none have the F marking. My oldest carbine is from 1987 and my newest one from 2009, so maybe the F front sight base is a later 2000's thing, I dunno.

The F-marked front sight bases are a mil-spec part and designed for use with flattop uppers. They will be too tall for carbines with rear sights on the carry handle like mine.

-Bob

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