m&p 15 rear sight

[artmcl]

I have been a member for several years but don't post very often.
I am an old man with over 50 years experience with every thing except ar's I currently do not a have rifle so picked up m&p ar15 ll.
I was just trying set basic iron sights zero before going to the range zero the rifle. the knob on the sight very hard to turn and skips dents I cant make that work. . Manual say to use small punch to press the small hole in the wheel. That doesn't either I know I sound like a complete noobe. I could sure use some help

 

[Kadonny]

I assume you are talking front site post.....and I assume you don't have a front site post adjustment tool. To improvise, some have said to use a pencil eraser to push and turn the post, but I could never get that to work. For me, I used a needle nose pliers with tape and a punch. Grab the post with the needle nose, push the detention pin with the punch and turn which way you need to adjust.

 

[sgtsandman]

Is it the sight that came with the rifle one one bought separately? It sounds like you are talking about the rear sight like one you would find mounted on a carry handle.

 

[artmcl]

rear sight

Yes it is the rear sight which came with the rifle

 

[McE]

The Magpul rear BUIS have a plastic knob to adjust windage, and it can be hard to turn.

I give the OP credit enough to know the difference between a front and rear sight.

 

[Kadonny]

It sure sounded like he was talking front sight to me. Sorry.

 

[McE]

They are polymer, so you may have just gotten one that was tight or jammed with extra material. The manual may have been unclear, you are not going to be pressing in the big round hole that's on the face of the wheel. The detent is a ball bearing in that half-circle notch you see directly below the wheel. THAT'S the hole you want to poke something into. Peek in there and you should see a shiny ball bearing as the detent. Stick a small punch or hex wrench in there to push on it, and the wheel will spin more freely.
If the wheel doesn't spin even when pushing in that detent, then your wheel is getting jammed up elsewhere.

 

[artmcl]

rear sight

thank you for you help. I long as it is more or less normal I will work through it. Thank you again.
Art

 

[matrsnot]

Once zeroed at 25 yards, what kind of max effective range can be expected? Mine is dead on at that range with the rear sight pictured above.

 

[McE]

I would reconsider that 25-yard zero, which is 6" high at 100 yards and doesn't come back down to within 6" of your point of aim until 325 yards.

Even if you don't shoot very far, a 50-yard zero would be worth a look.
You also have to be very careful about how you're defining "effective range". Effective at what? Punching through a piece of paper or fragmenting inside a human being?

 

[jimbo728]

Absolutely correct on the POI info using a 25 yd zero. Recently when zeroing a scope at 25yds, the POA with 55gr FMJ`S the impact at 100yds was 7" high. If you can zero at 50yds you should have better results and easier elevation adjustments at ranges out to 200 or more.
Good luck with the new rifle. One other thing that comes to mind is that you may wish to consider an all steel A2 type rear sight adjustable for windage and elevation. One of those came on my early Sport and I never had the need to touch the front sight post. It has a flip rear sight, small peep and larger aperture combat sight.
Nice chart...
Jim

 

[matrsnot]

Thank you both. My first zero was done on an indoor range. Will have to wait for weather to clear to get beyond that. Effective range for me is not just punching paper targets. This is my first experience though with these type of sights and a flat top. I used the M16 for a good many years and it is a different animal when zeroing and using.

 

[Tbat]

If you only have a 25 yard range to work with you can adjust your elevation to where you are hitting about 1 1/2 inch below your point of aim at 25 yards and and that will put you in the ballpark at 50 yards. Of course you will want to verify and make any necessary adjustments at 50 once you get access to a 50 yard range.