I have a slab side SP1 upper with A1 sights.  How come the rear flip apiture has the same size holes on it??  My A2 sights have both a large and a small hole.

Anyone?

Sgtar15

One's for longer range on the A1.  There is no other adjustment for range on the rear sight.  On the A2 you have the range drum, so the flip for long range became redundant.  On the A2 they used a bigger hole on the short range tang because it's easier and faster to use at close range and low-light.  If you need to shoot at longer range, you flip to the smaller hole and use the range drum.  

You can use a larger hole on one of the A1 legs as well, but since there's no drum, you'll loose the more preceise sight alighnment at short range.

Ross

But the 2 holes on the A1 are both the same size!!  See why I am confused??

Sgtar15

Quoted: But the 2 holes on the A1 are both the same size!!  See why I am confused?? Sgtar15

One sight is higher than the other.  I can't remember how they are graduated, but the longer range one is like 100-200 meters offset from the other sight.

The long range site is stamped with an "L", or at least my Colt SP-1 is...

Quoted: But the 2 holes on the A1 are both the same size!!  See why I am confused?? Sgtar15

The AR started out with holes the same size.  It's just one leg is longer than the other (the one marked "L") which raises the rear hole higher for longer range.

With the A2, you don't need different range legs because you have the range adjustment drum.

They simply made a bigger hole in the shorter leg on the A2 so you could shoot at shorter range, moving, low-light targets easier (which is what most of the targets in combat are).

The A1 type sights, without any other range adjustment than the flip, have the same size hole so that you get the same accuracy at all ranges.  On the A2, you get the same accuracy at all ranges because you flip to the small hole and use the range drum.  It also gives you the added benifit of the larger hole at shorter range/low-light.  The larger hole isn't as accurate, but it's a "hole" lot faster.  

Ross  

OH!  Now I see!!  

Thanks

Sgtar15

They are on differnt sight planes. non marked is 250 yrd zero and "L" is 375 yrds. To zero shoot 25 yrds with the L aperture, once you are sighted in like that, you will the weapon zeroed @ 250 & 375.
GG

Incidentally, Ashley Outdoors sells an aftermarket “same plane” rear sight leaf in which the two holes are different diameters but the same height.

So for an A1 carbine, wouldn't you want to have the "L" one replaced with a bigger hole A2? Since most shooting would be from 100 yards or less?

If the "L" one can be replaced with a big hole A2, are there any problems with doing it?

Quoted: So for an A1 carbine, wouldn't you want to have the "L" one replaced with a bigger hole A2? Since most shooting would be from 100 yards or less? If the "L" one can be replaced with a big hole A2, are there any problems with doing it?

You can put an A2 apeture on the A1 Rec. no probs. But you get a 200 M sight and a 300 m sight. I ll take the A1 250y 375y sight anyday. As for fighting less than 100 m is suicide and traing for such is also. I plan to start shooting at 400 yds., and I will use a cowardly but safe for me sniper aproach. I would always avoid a CQB situation. CQB is for idiots and people that have to do it.
GG