Ok guys setting up my rifle to have as little recoil as possible. So far got a go gun comp, superalitive gas block and lightweight bout carrier assembly. My question is do I use a collapsible stock system or a fixEd stock?

Is this a 5.56?  You don't have to do much to make it not have any recoil honestly.  

Best recoil reducing stock would probably be an ACE with a 1" buttplate.

What recoil?

if you want to fool with different buffer weights, the rifle buffer uses 5 steel 1/2oz weights, and it is pretty simple to remove one or more and replace with a piece of 1/2" aluminum round... removing 2 produces a 4.2oz buffer which is the approximate weight of a more expensive tungsten filled carbine buffer... I have an Enidine hydraulic buffer in my 3 gun rifle (16" with Miculek comp, A1 rifle stock)

This is going to be a 3 gun rifles sorry I did not mention this. I figured running a full rifle stock would be the way to go.

go with 18" barrel with rifle gas and a super light weight BCG and brake.

My experience has been that an A1 or A2 stock with a rifle length buffer system is smoother than an M4.

I have a 7.62x39 build that ran a 5 oz carbine buffer/M4 stock, then swapped out for a std. 5 oz rifle buffer/A2 stock. The A2 stock was SLIGHTLY easier on recoil. May be just the added weight of an A2 stock.

But I'm back to the M4 stock when I swapped my red dot for a compact scope, couldn't bring the scope back far enough. An A1 length probably would have worked.

An A2 filled with weights will reduce recoil more than any other stock. Physics and all. If you're trying to save weight at the same time, it probably doesn't matter what kind of stock you use.

Exactly.

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If the number one goal of this rifle is to have as little recoil as possible then go with fixed A2 stock sense it has longer spring action. Pick the lightest moving components like the bolt and the carrier, buffer, spring. Get the biggest muzzle break you can find. The rest of the gun needs to be as heavy as possible. If you want to step it up a notch, reload your own 223. Load 55gr pills down to about 2000 fps and tune your rifle to it. That will make very soft shooting center fire rifle.

Gonna go with the magpul fixed stock. Thanks guys

You want to go with a lighter buffer with a carbine buffer spring.  What your looking for is having the lowest reciprocating mass as possible using the adjustable gas block to tune the gun.
Two of my gun game AR15s have a JP low mass carrier, adjustable gas block, Lantac dragon brake, carbine buffer with one weight removed, and a carbine buffer spring.
The other AR has an aluminum carrier, adjustable gas block, plastic delrin buffer with a 10% reduced power buffer spring, and Lantac dragon brake.

Ignore those that say stupid shit like oh it's only a .223  round, what recoil.

It is not stupid, the felt recoil on a .223 or 5.56 rounds is actually very little and I have shot the platform a lot over the years.

Same here. Nearly 40 years for me.

I will say that in the case of a 3-Gun competition AR running light loads, reducing muzzle rise, controlling recoil, and having a lightweight trigger is essential. You want a speedy transition between each shot and be on target. These are not precision ARs, but they do need to be tuned properly to give the shooter the best possible performance and results. In saying that, everyone has their own idea as to how they want their 3-Gun AR set up. Some keep it simple, while others go to extremes. All in all, it is the ability of the shooter that makes the biggest difference. Going with the MAGPUL fixed rifle stock would not be my choice. Like I said before I deleted my earlier post, the A5 intermediate system is my choice. It combines the smooth recoil if a rifle buffer system and the adjustability that a carbine stock provides.

That is my .02 worth and all I have to say on this subject.

Did you bother reading what the op wanted?  He wants to build a gun with a specific need in mind.  In this case a race gun with as a little of recoil and muzzle flip as possible.  Anyone that competes in gun games wants this regardless if they shoot rifles in 3 gun or pistol in ipsc.  Go shoot a tuned race gun ar15 and a regular ar15.  There is a huge difference.  How many carbine matches or 3gun matches have you shot?  Can I expect to see you in a 3gn regional next year?  

I have been shooting 3 gun for a really long time now, so yes, I did read what he wrote.  I also compete in Machine Gun Competitions, long range competitions and just about anything you can think of when it comes to guns, I am a FFL/SOT manufacture of gun items.

Those of us, that compete, choose the .223 because of the low felt recoil for a large caliber firearm.

Add weight.  The heavier the rifle the less felt recoil.  A good ported muzzle brake will help.

Adjustable gas block and a muzzle brake would be top priority over anything else for recoil reduction.

Is the a5 buffer system a something only offered by bravo company? Does it use a rifle buffer or carbine buffer?

And yes this is a 3 gun only rifle. Is the 3 gun forum still going?

The A5 system was designed by VLTOR and they offer both a 7 position (RE-A5) and a 6 position tube (RE-10/A5SR).  They are slightly longer than a standard carbine extension, but essentially the A5 gives you a rifle buffer system in a carbine-like package.  The buffer is proprietary, but roughly the same weight as a rifle buffer.  However it is shorter than a rifle buffer, and longer than a carbine buffer.  The A5 also uses a rifle spring instead of a carbine spring.  It does a good job of smoothing out the recoil impulse, though in my opinion it is not ideal for what you want to accomplish since it adds reciprocating mass.  If you go A5, go with the lightest possible buffer (3.8oz), or get the Taccom delrin buffer for a rifle and trim it to length.  

I think the word "recoil" gets misused in these discussions for what is really muzzle deflection caused by the action cycling. I think clarifying the terminology is helpful for understanding how to mitigate it.

Recoil is the force transmitted to the shooter by discharging a round. .223 has very little recoil. Putting things (like weight) on the rifle that absorb that energy before it gets transmitted to the shooter is the only way to reduce recoil.

For speed-based competition games with an AR, muzzle deflection is as big or an even bigger issue than recoil. In an AR, the bolt hitting the barrel extension as it chambers a new round causes some muzzle deflection. Sometimes, the buffer bottoming out on the end of the receiver extension causes muzzle deflection. I don't consider parts banging around inside the rifle during the firing cycle to be recoil. Maybe that's splitting hairs too finely.

A lightweight bolt carrier group paired with an adjustable gas block can reduce muzzle deflection caused by the BCG and the buffer. Strictly speaking, a lightweight BCG will increase recoil because all reductions in weight in any rifle increase recoil. I'm not sure that anyone could discern this increase in recoil because of the minimal recoil a .223 has combined with the minimal weight reduction and the corresponding decrease in muzzle deflection that happens at the same time.

Muzzle brakes can decrease both deflection and recoil, plus annoy people around you.

I'm not sure if adjustable gas blocks by themselves reduce recoil or just reduce muzzle deflection by slowing down the BCG, but I do like them.