Front Sight Post too fat?

[David4516]

Hello THR,

I'm thinking about buying one of those "thin" front sight posts for my AR-15

Looking at this in particular:

http://www.midwayusa.com/product/84...wide-dcm-cmp-ar-15-matte?cm_vc=ProductFinding

I'm finding that with the standard post on a carbine length gas system, the post looks really big/fat, as in it is wider than the target is. What I've been shooting at is black paper plates (buy them in 20 packs for $1, cheap target easy to see at distance without scope, I think they're about 7 inches or so in diameter). At 100 yards I can keep my my shots on the plate no problem. At 175 yards (the longest distance I've tried thus far) I can only hit the plate about half the time. I'm wondering if a thinner sight would allow me to shoot more precisely left/right

I know there are a number of factors here, including human error (probably a big factor as my eyesight sucks) and ammo (I'm using cheap reloads with 55gr bullet and mixed brass, not weighing each charge individually, so the ammo is probably not what you'd call "match grade"). I'm thinking this thinner sight might help a little but probably won't solve my problem 100%.

So all this leads to my questions:

#1: Is there any big disadvantage to using thinner front sight? Should I just stick with what I've got?

#2: Do I have to re-zero the gun if I change out the sight? Or can I just count how many "clicks" it takes to remove the old one, and then screw then new one in the same number of clicks? I assume the answer to this is "yes you need to re-zero" but I'm curious.

 

[dmurdach]

I dont know about any disadvantages, maybe not quite as sturdy being that its thinner. someone wiser may chime in with another reason.

On one of mine I measured how high the post was off the front assembly, took it out, chucked it in a drill, and held it at a little bit of an angle to a file and narrowed it to more of a cone shape. Then reinstalled it to the same height and was still right on.

 

[WNTFW]

Try it, it is the only way for you to know.

#1 - In my opinion no. There are some disadvantages also, in my usage. Harder to see in low light. Harder to center up in a COM hold. A little sticking out on both side beats too short on each edge.

#2 - Don't count clicks, measure height as in post by dmurdach.

How are your groups looking? Where are the misses?

 

[Ohen Cepel]

You could file the one you have down some and refinish it. If you mess it up, buy the one you are thinking about. I also think if you did that well it would have sharper edges and be better.

I never felt a need for a skinny front sight for my M16/M4/AR but I know some precision shooters who prefer it. Preference and purpose.

 

[WNTFW]

You may be fighting something other than sight post width.

https://www.youtube.com/watch?v=gp69CCY71d4

 

[readyeddy]

I'm not a fan of thin front sights. It's more important that it is shaped crisp and clean.

Once you get out to 100 yards or so, most of your targets will be smaller than your front sight. Not a problem. Just put the target in the middle of the front sight. You'll be surprised how tight your groups can be shooting off the bench with iron sights that are bigger than your target.

 

[Mike C2]

I am a fan of smaller front sight posts, but I'm not worried about the target shooting back.
The NM front post at .050 blade is a good start. KNS Precision makes an assortment of front sight posts you can buy. Reduced square at the top, thin with a ball on top in a couple of sizes, ^ on one flat and v on the other flat, etc. Assortment of 6 is $20 or so.

Tapco makes some plastic ones that are flourescent colors. You can file them down to any width you want (within reason!).

Also, flourescent model paint can help the thinner blade stand out ala the orange insert on a S&W front sight.

 

[Laphroaig]

my eyesight sucks

In the OP you mentioned that your eyesight isn't that great. As shooters get older they typically gravitate to wider front sights so they can see them (a little better). While a thinner sight might better match the size of your plates, if its blurry you'll still never hit them. I think that post #6 had some good advice.

Laphroaig

 

[greyling22]

just paint your existing sight in thin vertical stripes. It's slimming.

 

[jmorris]

I do have a few AR's that I use thin posts on. This assortment will allow you to find one that will fit your needs.

http://www.brownells.com/rifle-parts/sights/front-sights/ar-15-front-sight-pack-prod13802.aspx

 

[David4516]

Regarding my eyesight, I'm not that old (yet), 33, will be 34 next month. I'm nearsighted though. I can see the sights just fine, it's seeing the target itself that gets tough, and the fat sight gets in the way making it that much more difficult...

I went ahead and ordered one with the .050 blade, will report back after I've had a chance to install it and try it...

 

[Sunray]

1) Not for hunting, but yes for target shooting. M1 Rifle NM sight blades are 10 thou thinner than standard sight blades. 60 thou vs 70, as I recall. Might be harder to see in low light for hunting.
2) You'll need to check it to be sure.

 

[IlikeSA]

Not an AR guy, but putting thinner sights on my revolver made a huge difference. They say the average revolver sight covers 40 inches at 100 yards. I'm not sure what a rifle sight would cover up, but sure some math guy could tell you. I believe a thinner sight may help you.

 

[David4516]

Well I got the new sight installed. Was a little difficult because my front sight adjustment tool, which worked great for the standard sight, didn't like the thin one for some reason. Had to use the tip of a bullet...

Anyway I re-zeroed it at 50 yards, it shot groups of 3 rounds into about 3/4 inch at that range. I figure that's OK considering the relatively low quality of both the ammo and my vision. It's an improvement over what I was shooting with the fat sight...

However, trying to hit the paper plate at 175 yards, I didn't do any better. I'm wondering if I'm calculating the trajectory wrong? I've got 55gr bullets, going about 2,800FPS, with a BC of 2.35, with a 50 yard zero. It should be just about dead on at 175 yards if I'm reading the ballistics charts correctly, but I seem to be hitting high. I suppose it could just be me...

Over all I'm happy with the new sight, it was only a few dollars and it did help me shrink the size of my groups, at least at shorter ranges...

 

[eastbank]

zero it at 175 yrds on a big target and then go back to 50yrds and see where you are hitting. i like a 27yd zero with a ar-15. eastbank.

 

[Bart B.]

When I was on the USN Rifle Team in 1971, we filed down our M16 front sights to appear as wide as the high power rifle target's bullseye's through 600 yards. They all subtend about 6 MOA and with the rifle's 20" sight radius for the Redfield target sight we put on them, their width needed to be about .033" wide to subtend that 6 MOA width. The three military teams there were the first ones to use the Mouse Gun in formal competition.

We tried one filed down so, but it seemed a bit small for most of us. A .040" wide one seemed better, so that's what we used. They appeared about the same on the round black bullseyes as the front sights on our 7.62 NATO Garands.

I suggest your calculate the width for your 7" plates at 100 yards that subtend 7 MOA. One MOA's equal to 1/3600th of the distance; range or sight radius. Then add about 10% so it appears a tiny bit wider than the black bullseye (plate) you're shooting at.

Taper its width to wider at the back so you won't see any bright side from light getting on the side of the blade. Taper the top down a little bit forward for the same reason. You should only see the back surface through the rear sight.