Can anyone shed any insight as to their......

Preferred twist rate. 1/7, 1/7.7, 1/8 (Cut vs button rifled)
Preferred adjustments on sights (I will be buying it with a carry handle so this is still relevant)  1/2-1/2, 1/2-1/4, or 1/4,1/4
Preferred front sight post width and size or rear aperture. (what issues would lead you to choose one aperture size over another and what are the benefits / disadvantages of going bigger or smaller?

I am well aware that almost any barrel will outshout the capabilities of the owner but if you were in buy once cry once mode who is in the top of the heap barrel wise. (what is your money and wait time are no object choice)

There are far too many manufacturers to list out but more than a few vendors websites include ....

Bartlein
Krieger
Douglas
Criterion

Krieger or Shilen .223 Wylde 1:7 twist for ~1.1" long bullets such as the 80.5gr Fullbore, 80gr ELD, and 77gr TMK. I've been using button rifled 1:8 and 50gr VMAX, 77gr SMK, 75gr AMAX to decent effect since upgrading from a 1:9 HBAR.

1/4x1/4. Necessity for High Master. I've made due with 1/2x1/2, but would prefer 1/4, especially for reduced range.

Standard 0.070" post works best overall (better for bright light and frame hold in the dark at 600yds), though the a 0.050" may help acquire NPoA at all distances. A slanted NM post should get rid of any extra glare, particularly at 600yds when you might be looking at the top of a regular post.

0.040 or 0.050" aperture seems a good inbetween for focus, and bright and dark days. Bigger tends to make the post less focused, but is better for dark days. Small should be better for bright days, but "shadows" crowd the post according to my eyes.

If you are a High Master, I'd invest in a Bartlein or Krieger. If you are on the way to HM, then a Douglas, Shilen, WOA, Green Mountain or any of the numerous others.

I like mine to be 1/7 SS.

B

Probably will never get there based on the amount of time I can invest in the sport.  But I do enjoy it regardless of my classification.

I do not have gear envy either but shoot around some people with nice toys, for curiosities sake what rail is on the closest upper. Is it a Geissele. (you might have to full screen it)

Yes it is. They are nice, but not really necessary. It's a little too wide for my tastes. One of my guns has it installed. I do love how easy it is to change barrels with one. Not timing of the barrel nut needed.

Back to barrels, they most all shoot good unless you get a bum one. I would not feel at a huge disadvantage with any of them, since it's still a shooting game.  

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When I choose to build a National Match AR (or M14 for that matter) I pick Krieger first. Most barrels will shoot, but I've seen a higher percentage of Kriegers shoot well and for a longer service life than any others. I've also noted that they tend to be on the money for land/groove diameter - out of say 10 barrels, 7 or more will hold multiple easily sub minute 10-shot groups at 300 yards in a fixture. In a pinch I'll shoot WOA/Wilsons, Saterns, Bartleins, etc. without fuss, but I won't go above 3,500 rounds on any stainless match AR barrel. I'd gladly toss it as soon as I see noticeable velocity loss or several uncalled flyers at the 300RF with a tight knot in the middle.

My preference is Krieger with 1/7.7 twist rate, AMU chamber, headspaced to 1.436 with a Colt or BCM bolt and a BAT Machine extension (basically a .223 Wylde with a really long throat set to jump 75gr. VLDs about 0.035" over 24.3gr. or so of H4895 out of a LC case), a fully bored out flash suppressor, Surefire shims used to time it with minimal torque and a bit of red loc-tite. Too much flash suppressor torque can actually constrict the bore. I prefer a smaller gas port of around 0.090". Most military guns are 0.096", but 0.092" will work fine as long as you clean it and keep it lubed well.  Mk262 likes this chamber too, so you're not losing anything at the short line.

For sights, 1/4 elevation is MANDATORY in my experience, 1/4 windage fine as long as you don't hesitate to move it 1/2 minute each time, 1/2 windage I actually feel is better as long as you can get a PERFECT no-wind zero. For irons WOA guide pins are the only way to go.

For irons I prefer a 0.040" WOA machined NM taper front sight, and a 0.040" rear short hood - this is all using an M16A1 or adjustable stock for a really close eye relief of 1-1.5". I want 2.5-3 minutes up from bottom for a 200SF zero to allow for flexibility in picking the hold I settle at. With this setup my preferred holds are 6 o'clock 200SF/200RF, 6 o'clock 300RF early in the season and center later in the season, and tight reverse flat at the 600SF. For the vast majority of shooters I suggest the same sight post but 0.052" diameter - not so wide you can't find lateral center, but not narrow enough to preclude those without perfect vision from shooting. I don't suggest more narrow than that for most. Any bigger and no-wind zeros appear to shift as you may not be able to track dead center with your eye, but elevation zeroes will be dead on (this is a generalization but seen across hundreds of shooters).

Hope this helps!

S/F

I had not even considered that and whether the bore size would be different from manufacturer to manufacturer

It's less that the vary from each manufacturer and more that a tight inner diameter (I.D.) brake can have really negative implications to precision. This is not exclusive to A2s either. I've seen Surefire and AAC brakes ruin precision of high-end bolt guns until a smart smith opened up the I.D. and precision returned. Simple version, it has to do with the tremendously violent release of gasses just behind the bullet and how the pressure/gas can literally deflect off the brake/FS and cause increased precession of the bullet at the worst possible time.

Though A2 flash suppressors are quite inconsistent in dimension from gun to gun in the first place, so one gun may shoot while another may not.

Don't open the flash suppressor up and the gun is likely to foul faster at the crown as well, something that won't be a precision robbing effect at first, but it'll catch up with you in time.

Just have a gunsmith bore that sucker out from the tight cone that it is to a parallel, straight-walled hollow cylinder, time it with Surefire shims to index with minimal torque, and use some red loc-tite or Rocksett.

S/F

Test Post

S/F

This

If I reload an already have Wylde chambered rifles, does it make sense to go CLE chamber if Wylde is offered.  Is it that much better of an option?

If you already have a Wylde chambered rifle, I would suggest sticking with that. The CLE Chamber for the most part has a much shorter throat and would require seating your 600 yard ammo to a shorter OAL. Although you could probably still shoot a 495 running your CLE ammo through the Wylde chambered rifle.

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