a good barrel is needed in 3 gun, IMHO. Maybe not a Krieger, but at least a quality barrel. A 16" midlength will work fine. Most 3 gunners prefer 18". If you go 18" a rifle gas would be better. 18" will deliver a little more velocity. Midlength will have a smoother recoil, a rifle gas system will have an even a smoother recoil. A 1:8 twist is nice. It allows a larger variety of bullet wieghts over 1:9. Most matches i have attended have at least some 200 yard shots. Some out as far as 450 yards. Over 300 is rare in most local club matches.
Bravo and spikes are great stuff. Del-ton would be ok. I would suggest looking at the Stag 3 gun upper. It is ready to go.
If you build yourself, the DPMS MK12 barrel is popular. 18" medium contour, black stainless, 1:8 twist and Nato chamber. One of my guns has this barrel. Sunday before last is was shooting 1-1/2" groups at 200 yards off a bench, no bags or sled using AE223 55gr.
A good muzzle brake will help you keep good split times with your 2 shots on paper. I like the SJC Titan. The Jerry Miculek is good to.
I run a stock full auto style BCG, Timney 3lb trigger, Spikes S-T2 buffer, CTR stock, MI SS-12 FF forend, Nikon African Monarch 1-4x on a American Defense recon mount and USGI mags (most use Pmags). I run AE223 55gr, Hornady steel match 55gr or Fed XM193 depending on what is the last bulk buy i got.
You can start with a fairly stock AR. Add the upgrades as you figure out what you need. I have not seen any 2 3 gun ARs the same. Everyone changes them based on their style and preferences. I started with a S&W M4gery.
