Question on sights > AR Basics

Posted: 8/19/2014 5:31:47 AM EDT

Hi to all
I have two MP15 Sport rifles. One I am going to set up with Nikon P223 scope and Magpul MBIS polymer sights.
The second one, I plan on using no optics (at least for now) and replacing the A2 sight with rail height gas block.
I was just about to pull the trigger (pun intended) on a set of DD rail mount fixed sights which come in about $125.
Part of the reason was that the Magpul front sight would likely not do well with the heat from the gas block.
But, decided it would be good to put the question out on the forum to get other ideas before purchasing.
Mr Mac

Posted: 8/19/2014 6:53:19 AM EDT

[#1]

Just what is the question?

Posted: 8/19/2014 7:00:15 AM EDT

[#2]

Sorry. The idea was to get some other ideas on rail mounted sights.
Did check on Knights, but they were too expensive.

Posted: 8/19/2014 7:05:19 AM EDT

[#3]

Chief,
You are right that the polymer sights aren't a good idea for a railed gas block. DD and Midwest Industries both make great fixed sights that can be mounted on the railed gas block.

Have you thought about adding a free float rail with a low profile gas block? if you did that, you could use the Magpul MBUS.

Posted: 8/19/2014 9:49:36 AM EDT

[#4]

Bedouin

That is the exact plan for the other MP15.
Have a 12" free float quad rail with LP gas block.
That will get the MBUS sights and Nikon scope.

Mr Mac

Posted: 8/19/2014 10:12:34 AM EDT

[#5]

I am pretty confused here. Why would you want to remove the A2 at this point? You should get on the EE and look up MATECH rear sights. You should be able to get one between 40-50 shipped easy and you are set. I have shot them with great accuracy in the past. I would also suggest buying a KNS .034 round ball post for your front sight base.

Posted: 8/19/2014 10:16:25 AM EDT

[#6]

Quoted:
Hi to all
I have two MP15 Sport rifles. One I am going to set up with Nikon P223 scope and Magpul MBIS polymer sights.
The second one, I plan on using no optics (at least for now) and replacing the A2 sight with rail height gas block.
I was just about to pull the trigger (pun intended) on a set of DD rail mount fixed sights which come in about $125.
Part of the reason was that the Magpul front sight would likely not do well with the heat from the gas block.
But, decided it would be good to put the question out on the forum to get other ideas before purchasing.
Mr Mac

View Quote

If you have no plans of installing FF handguards on the other, why not keep the A2 FSB there and just add the MAGPUL MBUS on the rear? If you ever to decide to add an optic of sort, you will still be able to use it and co-witness your iron sights. This saves you a lot of needless work and expense. Here is a picture of what I am suggesting.

Posted: 8/19/2014 11:05:37 AM EDT

[#7]

Removing the fsb for a railed gas block is a down-grade for more experienced guys. Why would you replace the far superior fsb with a rail and then put some flavor of rail mounted sights?

Shave it and do a free float or leave it be.

Posted: 8/19/2014 1:52:42 PM EDT

[#8]

I'm with the majority here...besides the fact that rail height gas blocks look like ass...keep the A2 amd use whatever you want on the rear.

Posted: 8/19/2014 7:45:22 PM EDT

[#9]

You can use polymer sights with a rail height gas block no problem. The additional height of the gas block dissipates heat well enough. Guntec has a decent rail height gas block as does Anderson Manufacturing. An alternative to the Magpul sights are A.R.M.S sights. They come in at around $100 a set. I have them on my rifle with a rail height gas block and haven't had a problem. You do have to be careful when buying Magpul sights especially on-line. Magpul PTS sights are made by Magpul but they are made in their Hong Kong factory for airsoft guns and are not the same quality as their US made MBUS sights.

Posted: 8/19/2014 7:51:05 PM EDT

[#10]

Quote History

Quoted:
I'm with the majority here...besides the fact that rail height gas blocks look like ass...keep the A2 amd use whatever you want on the rear.

View Quote

Not exactly. The Guntec rail height gas block is angled at the front. It actually looks really good on a rifle. That's what I put on mine.

Here's how mine came out:

Posted: 8/19/2014 11:23:44 PM EDT

[#11]

Heads up on the Nikon P223 scope. Proper placement of the scope for eye relief will make the rear BUIS useless unless you have a QD mount for the scope.

Posted: 8/20/2014 5:31:59 AM EDT

[#12]

Wow, Just like I had hoped. Lots of good input.

Mr Mac

Posted: 8/20/2014 8:26:34 AM EDT

[#13]

Quote History

Quoted:
Heads up on the Nikon P223 scope. Proper placement of the scope for eye relief will make the rear BUIS useless unless you have a QD mount for the scope.

View Quote

The solution to that is a Midwest Industries SPLP (Same Plane Lowe Profile) rear sight.

It is advisable to get a QD mount for the P223 scope. The one I used on this build is a LaRue Tactical SPR/M4 QD Mount (LT104-30mm). They do cost a little bit, but are darn well worth it. That said, here is a pic of another build using a Burris P.E.P.R. mount with a MaTech 0-600M BUIS. Both scope are the Millett 1-4x24 DMS Tactical 30mm Riflescope, Matte, Illuminated Donut-Dot (BK81002).

A QD mount does allow for expedient removal of the optic should it become damaged and non-functional. In most cases, under normal use, you would never have to worry about this. In the other case with a red dot optic, you can just flip up the rear sight and co-witness right through the optic and keep on rockin' and rollin'.

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