A2 build

For a true A2 clone, you probably need a straight trigger guard rather than a curved one.

Also make sure the front sight tower is not "F" marked.

Nothing wrong with the stock trigger.

JCSC said:

View attachment 928289 View attachment 928290 When I was younger I couldn’t stand the look of these, but I was drawn to having one in my collection and this is my finished build.

I have only tested for function and about 4 rounds, but surprised how smooth the rifle length system functions.

I plan to upgrade the sights eventually, so they have the fine adjustment and repeatability. The trigger is box stock, so it needs some work.

20” 1-7 chrome lined and as close to a clone as I wanted to get.

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Looks great!

JCSC said:

the front sight is non F marked for the upper with the integral hand guard.

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Yes, that's correct. The "F"-marked ones are for flat top upper receivers, that would presumably take a clamp-on carry handle. The clamp-on carry handle is a bit taller than the integral one, and so the front sight needs to be taller.

I recently had difficulty finding a non-"F"-marked front sight tower for a retro build. I ended up going ahead and building it with the "F"-marked tower, even though it isn't correct.

AlexanderA said:

...I ended up going ahead and building it with the "F"-marked tower, even though it isn't correct.

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Did the combination of the F marked FSB & fixed "carry handle" give you any trouble with elevation when sighting in?

MistWolf said:

Did the combination of the F marked FSB & fixed "carry handle" give you any trouble with elevation when sighting in?

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You have to run the front sight down and/or run the rear sight up, which cuts your further adjustment range. Also the gun looks odd with the rear sight run up.

I'm pretty sure I've got a straight guard you can have for the price of postage. I overpay for plastic ones without sharp edges.

AlexanderA said:

You have to run the front sight down and/or run the rear sight up, which cuts your further adjustment range. Also the gun looks odd with the rear sight run up.

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I figured that'd be the case. It looks to me like if it's zeroed with front and rear bottomed out, you have full range of elevation on the 6/3 drum.

I have a very similar model, built on a bushy lower, and use straight 20 round mags. These rifles can be shot at man size targets out to 800 meters, in the hands of a "just ok shooter" from a rest. Only clear difference is my straight trigger guard. I used to shoot it in Yakima Wa, and the straight guards are much more glove friendly, really odd when you see the oversize guards advertised for use with gloves. Anyway, for the first time this year, I bring it out and people look at me like its a flintlock. "Wow how old is THAT?". Strangely back in 2006 when I got it (when most OIF/Afghanistan recruits were still in the military) it was looked at like some crazy space gun from the future.

mustanger98 said:

I figured that'd be the case. It looks to me like if it's zeroed with front and rear bottomed out, you have full range of elevation on the 6/3 drum.

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On an A2, it should have the 8/3 drum.

As far as having a F marked FSB, yes you will have to go lower with the front sight pin versus a standard FSB. No matter if it is a A2 or flat top, the rear sight is always sighted in with it down at either the "Z" mark for 6/3 drums or 1 click past 8/3 per Army manuals. All elevation adjustments during sight in should always be made with the front sight.

OP, ditch the curved trigger guard for a straight one to make it correct.

I had to build an A2 clone a couple of years ago to go with the M7 bayonet sitting in the safe. I like taking it out to the range along with my 1911 for nostalgic reasons. Plus I like outshooting the youngins with their carbines with all the fancy optics on them.

12Bravo20 said:

On an A2, it should have the 8/3 drum.

As far as having a F marked FSB, yes you will have to go lower with the front sight pin versus a standard FSB. No matter if it is a A2 or flat top, the rear sight is always sighted in with it down at either the "Z" mark for 6/3 drums or 1 click past 8/3 per Army manuals. All elevation adjustments during sight in should always be made with the front sight.

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What exactly is the meaning of the 6/3 and 8/3 and the Z mark?

mustanger98 said:

What exactly is the meaning of the 6/3 and 8/3 and the Z mark?

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On removable carry handle sights, the sight drum is marked 6/3 for 300 and 600 meters. The 6/3 drum was developed for flat top uppers since the sight sits a little higher than on the A2 receiver. The 6/3 drum has a Z mark on it that is used for zeroing the rifle/carbine. The 8/3 drum is normally only found on fixed handle A2 upper receivers and is for 300 and 800 meters.

Here is a photo of a removable rear sight. It has the 6/3 drum and you can see the Z (for zeroing) to the right of the 6/3 mark. Normal use is to have the rear sight on flat tops set at 6/3 and you rotate the drum to the "Z" mark when you initially zero the weapon. After zeroing, you return the drum to the 6/3 mark.



With the A2 8/3 drum, you turn the drum down/lower 1 click past 8/3 for zeroing the rifle. Once zeroed, you move the drum back to 8/3

12Bravo20 said:

On removable carry handle sights, the sight drum is marked 6/3 for 300 and 600 meters. The 6/3 drum was developed for flat top uppers since the sight sits a little higher than on the A2 receiver. The 6/3 drum has a Z mark on it that is used for zeroing the rifle/carbine. The 8/3 drum is normally only found on fixed handle A2 upper receivers and is for 300 and 800 meters.

Here is a photo of a removable rear sight. It has the 6/3 drum and you can see the Z (for zeroing) to the right of the 6/3 mark. Normal use is to have the rear sight on flat tops set at 6/3 and you rotate the drum to the "Z" mark when you initially zero the weapon. After zeroing, you return the drum to the 6/3 mark.

View attachment 928576

With the A2 8/3 drum, you turn the drum down/lower 1 click past 8/3 for zeroing the rifle. Once zeroed, you move the drum back to 8/3

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Normally, for almost any other iron sighted rifles... let's say Garands and Mini-14's... all our zeroing and adjusting takes place at the rear sight as the front sight doesn't move. (Most of us are also not zeroing a Mini-14 beyond 300yds/m... most of those probably 200 or less depending on who's rifle.) Now, with an AR-15A4, we're talking about setting the 6/3 drum to Z, zeroing elevation with the front sight, the re-setting the drum to the 6/3 position. What is the difference in elevation, generally, from Z to 6/3?

Then, there's the short and long range aperture? I know they're different diameters. I had previously assumed they were 300 and 600 yds or meters (generally same as a 300/600 flip sight on a No4Mk1). I've seen references to zeroing AR's at 25/300 using the long range aperture, then switching to the short range aperture. What's going on there?

mustanger98 said:

Normally, for almost any other iron sighted rifles... let's say Garands and Mini-14's... all our zeroing and adjusting takes place at the rear sight as the front sight doesn't move. (Most of us are also not zeroing a Mini-14 beyond 300yds/m... most of those probably 200 or less depending on who's rifle.) Now, with an AR-15A4, we're talking about setting the 6/3 drum to Z, zeroing elevation with the front sight, the re-setting the drum to the 6/3 position. What is the difference in elevation, generally, from Z to 6/3?

Then, there's the short and long range aperture? I know they're different diameters. I had previously assumed they were 300 and 600 yds or meters (generally same as a 300/600 flip sight on a No4Mk1). I've seen references to zeroing AR's at 25/300 using the long range aperture, then switching to the short range aperture. What's going on there?

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Normally we would zero the rifles/carbines using the bigger 0-2 aperture at 25 meters with the 8/3 drum 1 click past 8/3 or with the 6/3 drum set to "Z". Once zeroed, switch the aperture back to the smaller long range aperture and you move the drum back to 6/3 or 8/3, depending on which you have. To properly zero a M16/AR15, all elevation adjustments during sight in are made with the front sight only. This is for zeroing using the 25 meter/300 meter battle sight zero per Army manuals.

I was able to find out there are 3 fairly long clicks between 6/3 and Z. I'm thinking those 3 clicks must make the difference between the 0-2 aperture and the long range aperture at 25m.

I have also seen comments where different ones zeroed their A4 at 50/200yds... I guess for lack of a 300yd/m range.

JCSC said:

View attachment 928289 View attachment 928290 When I was younger I couldn’t stand the look of these, but I was drawn to having one in my collection and this is my finished build.

I have only tested for function and about 4 rounds, but surprised how smooth the rifle length system functions.

I plan to upgrade the sights eventually, so they have the fine adjustment and repeatability. The trigger is box stock, so it needs some work.

20” 1-7 chrome lined and as close to a clone as I wanted to get.

Click to expand...

I'm assuming the "Burst" position on the safe/fire selector is purely cosmetic, but how and why did you go with having your receiver marked US Govt Property? Seems to me you may be creating a legal problem for yourself down the road, not withstanding that the PSA roll mark nearby obviously marks the rifle as commercially made.

mustanger98 said:

I was able to find out there are 3 fairly long clicks between 6/3 and Z. I'm thinking those 3 clicks must make the difference between the 0-2 aperture and the long range aperture at 25m.

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I could be wrong, but I kind of don't think so. The A2 was the cutting edge when I was in the Army (and, in my opinion, remains so, but what do I know) I've never worked with a 6/3 drum, but the clicks between 3 and 8 on the 8/3 drum were long, and each detent was 100m. You zeroed on Z at 25 m then set the drum to 8/3 and you should be just about on at 300. From there, go up to 4, 5, 6, 7, and 8...hundred meters. 8/3 is the same position on the wheel, but there is a full rotation between them. As I always understood it, the 0-250 aperture was larger in diameter for more light coming through the sight and faster target acquisition at the closer ranges. The L aperture (or however it was marked) was for 300m and beyond and was smaller in diameter for more precision. However...the older A1 rear sight had two different apertures and they were at different positions (heights) and they actually changed the zero for shooting at longer ranges.

mustanger98 said:

I have also seen comments where different ones zeroed their A4 at 50/200yds... I guess for lack of a 300yd/m range.

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What I understand of this is some guys (who I don't know, is this GIs doing this or just civilians?) are zeroing their ARs at shorter ranges due to the sight offsets and holdovers required by the tall sights on the AR to be precisely on target at shorter ranges. If you zero an AR at 300m and your target is 75m away, your point of impact will not match your point of aim. (I don't know all the math behind that because we were taught to zero at 300 and you'll hit your target within a few inches of point of aim anywhere from 0-300 meters. I secretly used a 6 o clock sight picture so I had to aim high on the 25m target to avoid hitting the dirt.)

JCSC said:

Good stuff. I haven’t sighted my 8/3 yet, but was planning to read up on the process.

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This is all you'll ever need to know about the subject.

And here is a link to a PDF of the Army 25 meter zero target for the M16A2 with an 8/3 rear sight drum.

When you print, be sure that your printer setting specifies to not shrink the image or fit image to the paper. Make sure it's set to print the original size.

http://www.bobdbob.com/~deneb/doc/targets/m16a2-25m-zero.pdf

Yes some people prefer the 50/200 meter zero and there are other improvised/improved battle sight zeros that you can use. To keep it simple as to how they sights were designed, use the 25/300 battle sight zero.

As far as zeroing the rifle at either 25 or 50 meters, that is what is called a battle sight zero that will get you close to actual distance zero. You should still shoot at the longer distance to verify your zero. With the 25/300 zero, you initially sight in at 25 meters which will get you close to being zeroed at 300 meters. to get your zero perfect, you still need to shoot at 300 meters to verify.

D.B. Cooper said:

I'm assuming the "Burst" position on the safe/fire selector is purely cosmetic, but how and why did you go with having your receiver marked US Govt Property? Seems to me you may be creating a legal problem for yourself down the road, not withstanding that the PSA roll mark nearby obviously marks the rifle as commercially made.

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I've been wondering about that too.