Where to mount MBUIS on AR (DD M4)

[poller]

I have a new (to me) DD M4 V7 LW. I just purchased front/rear Magpul BUIS.

Where on the rails (how far forward or to the rear) do I mount the sights?

Thanks in advance

[Varg Vikernes]

As far as you can for both.

[tal3nt]

The rear might have to go on the second notch if I remember correctly..?

This way, when folded down, it won't hang over the receiver

[poller]

Thanks

[tal3nt]

Also, although ideally you would want to put the front sight as far forward as possible to maximize your sight radius, I've found that when having it too far forward on an extended length railed freefloat handguard, I had to make pretty extreme elevation adjustments to my front sight. Otherwise it would hit way low. Just mess around with it until you find "the butter zone". And always have that front sight tool handy at the range.

[Big Ragu]

Looks like the front sight is in the first slot and the rear is in the second on my DDM4V5. Gen 2 MBUS

[jasonnorcal]

As far towards the back and the front as possible. Its ok if it hangs off the back a tiny bit

[k1dude]

Make sure the rear sight isn't so far back it interferes with your manipulation of the stock charging handle. Some people with big hands and fat fingers have a problem with that. Especially if your BUIS has sharp edges to scrape your fingers on or hang up your gloves during winter.

I prefer the rear sights mounted a little more forward for better finger clearance. It's much easier to manipulate the charging handle under stress when it's clutter free. The extra half inch to an inch of decreased sight radius isn't going to make much of a difference on your accuracy. But keep in mind that some rear sights require you to mount as far back as possible like the GG&G A2 BUIS, where the rear sight is scalloped to match the termination of the top rail (and the sight won't lay flat if you mount it more forward). I don't like sights like that because inevitably the windage knob intereferes with grabbing the right side of the charging handle.

If you still want the rear sight all the way back, consider a larger charging handle for ease of manipulation - like the BCM Mod 3 or the BCM or Rainier Arms ambi charging handle.

[PhillyGunner]

I prefer the rear sights mounted a little more forward for better finger clearance. It's much easier to manipulate the charging handle under stress when it's clutter free. The extra half inch to an inch of decreased sight radius isn't going to make much of a difference on your accuracy.

If you still want the rear sight all the way back, consider a larger charging handle for ease of manipulation - like the BCM Mod 3 or the BCM or Rainier Arms ambi charging handle.

K1dude:
You might like the new Magpul MBUS PRO sights, if you can find them in stock. They are both light and unobtrusive and the rear is particularly narrow and, except for the mounting area, is well within the edges of the top of the receiver. Vast improvement, dimensionally, over the polymer MBUS, IMHO.

OP: The flip-up BUIS sights are generally designed for the rear to sit as far back on the receiver as possible (without backing 'over the edge') and for fronts, as Tal3nt pointed out, if you go forward of where a carbine post sight would be, you may need to add the taller front sight post (Bushmaster & others sell) to get enough height to zero without unscrewing the post from the base.

[trigger945]

The rear might have to go on the second notch if I remember correctly..?

This way, when folded down, it won't hang over the receiver

+1 on this. Although it can hang if that's your preference.

Front sight I would recommend to install as far as possible.