OK, this may be a stupid question, and a tired subject for some of you, but I'd like some advice. First of all sights.

I like the A2 sights, but am wondering if they are overated for combat purposes. I like the fact that you can sight them in a little tighter, but wonder, how much tighter? Are they more suited to match shooting? Or do you think that having the option to dial in a shot at 400 yards is worth the chance that your sights might get bumped and misaligned?

Also, I've heard some people speak of wandering zero with the A2 sights. I've noticed that my shots vary from time to time with my A2 sights. Is wandering sights an urban myth?

Also, since I'm building an M4, I'm wondering if I should stick to the A2 since it would be more to the original, and if I'd even notice a difference with a 14.5" barrel.

Suggestions?

Actually, the more original route would be a flat-top with a DCH (detachable carry handle).  You get the A2 sight system, and if you want you can remove it and attach scope or red dot type sight.  Aimpoints are wonderful little sights, and make shooting a lot of fun.  

Yes, if you want "M4" go with a flattop and carry handle.

A2 sights are fine for most purposes and are a huge improvement over A1 style. I have my M4 carry handle set up for a 50/200 zero, then I can dial in 300 or farther if needed.

Only time I have ever really had to change my sights is on my A2 match gun, and that's because you go from 200 yards, to 300 yards, to 600 yards, and have to adjust for windage.
On my M4 I am almost always shooting under 300 yards, and never bother to adjust for windage.

So it just depends on what you want. A1 sights can't be changed easily, and are not adjustable for elevation, so you'd be stuck with whatever zero you made it for. A2 sights are easily adjustable, and "might" get changed on you, but it is very highly unlikely it will. There isn't too much weight difference, and A2 sights are plenty durable, so you might as well get A2. Unless you are counting fractions of ounces for a superlightweight upper, I wouldn't bother with A1's. You'd just end up upgrading to A2 or flattop after a while anyway.

Don't know about "wandering zero". Never experienced it. Maybe someone making something up to explain their poor shooting???

gonna have to agree with forest on this one, i have a stock bushmaster 20" with the A2 sights, i'm working up a pre-ban m4 now, and i will be going with A1 sights.  50/200 zero is exactly the same reason; most battlefield shooting is done at closer ranges, not 300-500-600 meters.  A1 for me thanks.

Same here. A1 is at least .1Lb lighter, I suspect more actually, but don't have a way to measure it. Simple, Strong, Absolutely all that would be needed in a real action scenario.

M4-AK

I’m also an A1 fan, light, robust, and simple.

[b]R[/b]ighteous [b]K[/b]ill

A1 sights all the way. If you use a true A1 front sight you get 5 "clicks" of elevation per revolution vs. 4 for the A2 sight. This is tight enough to get your elevation spot on. For the rear, windage knobs are available (though I've never seen the need) that have holes drilled in between the stock ones, effectively "doubling the available "clicks". Then if you use an A1 rear aperature you can have two different zeros. One that shoots real damn flat out to about 200 yards and one that is on at 25 yards and again at about 350 yards but is high by as much as 8 inches in the intermediate distances.
Paper punchers will, of course, disagree.

#1 If .1 lb for the sight makes such a difference, why not just get a 16" skinny barrel and save another .5 lbs?

#2 I can have the same zero with A2 sights

#3 I agree. I have never encountered any accidental changes on A2's, though it is possible but not possible with A1 sights.

The .1 lb savings alone really isn't enough to make me want to not have A2 sights. Especially since I don't plan on getting sent to combat any time soon, so what do I care. Considering the M4 barrel weighs a full half pound more than a 16" skinny, I don't see what big deal the .1 lb makes.

In fact my flattop with M4 barrel, Phantom and carry handle weighs in at 3.4 lbs. With M4 handguards it's STILL as light as a government A2 upper, which isn't heavy at all.

As I said before unless you are counting half ounces for a superlight upper, it won't make much difference. For lightweight I say get an A1 upper with a 16" skinny barrel. That weighs in at 2.4 lbs. Get a colt shaved bottom carrier and take the heat shields out of a set of regular carbine handguards and you'll be all set. THAT's lightweight, but not M4 which I kind of thought the original question was going for.

So it just depends on how close to "M4" you want to stay, how durable you need your sights to be, how much weight is a factor, and if you may need to make any expedient sight corrections in the field (though highly unlikely).

For an "M4" the flattop is nice, because you can add on all sorts of neato gee-whiz optics when money allows. Otherwise A2's are plenty durable and are more likely to be at the range then in "combat". A1's are indeed the most durable and save .1 lb on weight over A2's, though they are pretty much set when you get your zero.

Just some interresting weight facts from Bushmaster's website:

XM177 Bbl. - 1.7 lbs.
M4VO Bbl. - 2.2 lbs.
20A2 Bbl. - 2.5
20" - Heavy Bbl. - 3.5

A1 Type - 0.7 lbs.
A2 Type - 0.8
Flat-top - 0.6
Flat-top - 1.2 (including weight of A3 Type Removable Carry Handle)