Just built a 20" woa spr barreled ar15 but can't decide which bcg I should get for it. I have a bcm; aero precision, and spikes bcgs for my other rifles but I want something really premium that will be the best in aiding in accuracy and precision.  Any suggestions?

JP would be my choice.

I was thinking either that or maybe geissele bc the top rails come all the way forwards to help with bolt carrier tilt but it's like 100 bucks more than jp so im not sure if it's worth that.

@molon

What bcg do you prefer for accuracy?

Try what you have and see if one beats the others.

JP is always a good choice.

On my Arc I am using a CMC and it is not hurting accuracy. I will use another in my next build.

Why not a Young National Match M16 BCG?

JP is as good as it gets.

Buy a quality GI bolt carrier group and don't worry about it. The premium BCG's won't improve anything on target.

Why not use a BCG from WOA?  WOA uses them and puts out quality stuff.

JP > thread

JP always headspaces the same and is the only bolt that the barrel maker can set minimum headspace without one in hand. You can send in any bolt when the barrel is made and have mini.um headspace set off that too. It does not matter what the bolt is... the only difference is some bolts vary in the headspace measurement so you can't always just buy any new bolt and have the original perfect minimum headspace unless it is JP.

That's the bolt.

As for the carrier... it makes absolutely ZERO difference what brand or weight or style of carrier you use. It has ZERO impact on precision. Light, heavy, parked, coated, milspec or custom it simply will not make any difference AT ALL. I have tried and tested all manner of carriers in my precision and non precision ARs. The only difference in a JP carrier, Toolcraft, and Young is the coating, style, and weight. Group size simply will not change.

Your precision comes from the BARREL and AMMO. Then the things that allow YOU to eek out all that precision, like the optic, trigger, etc.

Put me down in this camp. If there is any difference, you would need a return to battery machine rest and shoot a large sample size.

I shoot High Power Service Rifle, I have a WhiteOak Service Rifle Upper with a 20" 1-7 Wilson barrel.  Just had it rebarreled before last season by WhiteOak for Camp Perry 2023.  

I shoot 600y easily with both a 77g SMK or 80g Hornady ELD with 24.1gr of Viht N140 IMI case and #450 Magnum Sm Rifle primer that I developed.  At 100y I one hole the 77g SMKs and get just under 1" group with the 80g ELDs.  

The original Wilson Barrel I was about 4000rds through it and it was still holding strong, one of my peers has close to 6000 on his and still holding up.  When WhiteOak rebarreled/refurbed my upper BCG had little wear and for good measure they replaced the cam upon their recommendation.  Gas seals, firepin, bolt was all still in spec.  I keep a spare set of gas seals and firepins with me all from WhiteOak.  

Can't go wrong with WhiteOak or any of those components.

My CMP/NRA High Power Match Service rifle is Magpul UBR Gen2 Stock, Stealth Ballistics weight,  Geissele H1 Super 42 Braided buffer system, Geissele Lower and LPK, Geissele High Speed NM trigger with Service Rifle Springs, and a Hi-Lux XTC scope.  Not super precision but the rifle shoot better than what I can shoot with it.  I have a second lower built on a S&W lower with a Geissele LPK, Magpul UBR Gen2 stock, Stealth Ballistics weight, Geissele H1 Super 42 buffer system, and Geissele SSA-E trigger.  I use this for NRA match rifle and I use the Geissele for Sanctioned CMP matches.  

For serious competition I would trust nothing else but WhiteOak/Geissele/Magpul.  

https://www.whiteoakarmament.com/complete-bolt-carrier-assembly.html

For good parts I went to WOA or Compass Lake. I can’t keep up with who makes good AR parts as companies change so fast. I knew if I bought from those companies the parts were going to good for precision service rifles. Now Compass Lake is out of the business so WOA is my go to.

My whole thought on this is you are not going to buy a random bolt from any maker and magically get better accuracy over any other.  If you want the best possible accuracy from a specific bolt you are going to have to have it measured and matched to your barrel.  Any in spec bolt will have slight variations and unless you are measuring and matching to your barrel you could get a JP bolt that is on the opposite side of best possible headspace but within spec and you could get a cheap PSA bolt that is on the good side of spec for your barrel.  So unless you are having it matched to your barrel buying any bolt I would think is a crap shoot.

The best bolt is going to be one that is headspaced with a specific barrel chamber.