I am in the process of building a precision Aero Precision M5 in 6.5 Creedmoor.  I currently have the Aero Precision M5 upper and lower.  I was just going to purchase a Aero Precision M5 BCG, but started seeing that a lot of people are going with JP Enterprises BCG over the Aero Precision ones.  My question is whether or not either will make much difference in the overall accuracy of my build?
Is it really worth the extra money for the JP bcg?  The second question is that I see that JP makes a regular and a high pressure bolt.  Why would I choose one over the other in a 6.5 Creedmoor build?
If it helps, I will probably use an adjustable gas block but not a suppressor.  Just to be clear, I don't mind spending the extra dough for the JP if it really makes a difference in the overall accuracy and shootability of my build but I don't want to pay for bells and whistles if there is no true benefit.  I plan on using either a Kreiger or Bartlein barrel from CLE on this build also.  I am anxious to hear comments back.

I can’t speak to accuracy difference between JP and Aero Precision however, on my AP M5 22 inch ballistic advantage barrel chambered in 6.5 CM I originally went with a standard AP bolt carrier group. I was having problems with pierced primers, after doing more research, I replaced BCG with a AP high pressure BCG and it fixed my issue.

3/4 MOA Rifle.

You need the smaller firing pin holes of the high pressure bolt faces. I have Aero BCG's in mine and they work well.
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Get the HP bolt.  It’s what I have in mine.  Too large of a firing pin aperture and you’ll end up with pierced primers and potentially damage to the bolt.

Mine is not a complete BCG, though, the carrier is from Fulton Armory.

I can’t speak to the difference, but JP was the best and most proven when I built mine, so that’s what I went with.  No ragrets.

I have pierced primers on my Remington 700 builds in 6.5 and had to bush them, so on my semi I didn’t want to mess around.  Buy once cry once.

So, to get to the point, how much effect does the BCG have on the overall accuracy of a barrel?  As stated above, I plan to buy my barrel from CLE and send the bolt in to make sure it is correctly headspaced to the barrel.

All bolt carriers are machined where the back of the lugs are parallel to the bolt face, because of how they are machined.  You likely won't see much difference from an accuracy perspective, outside of the debate on smaller firing pins and small primer brass yielding better results.  However, this level of margin is negligible when we are talking about a gas gun.

If you are looking to increase accuracy in what you purchase, your focus should be on the quality of the barrel, and then tuning custom ammunition for that barrel.

My two builds are sub MOA guns with the Aero BCG's.

I 100% agree with FALARK.  Barrel is the biggest issue.

I just got finished looking at the Aero Precision and JP BCG for the 6.5 Creedmoor.  I have just got to ask the question...what am I really getting for double the price for the JP over the Aero BCG.  Roughly $425 for the JP models is a pretty big pill to swallow if there aren't any huge advantages.  What are the true advantages of the JP over the Aero?

Mine uses a 22” custom barrel made by Craddock Precision from a criterion blank and was lapped, broken in, then nitrided.  Gas length is Rifle +2” and I had Craddock cut headspace to my bolt for factory 147gr Hornady (I sent in a RCA Titanium adjustable BCG with HP small FP hole).  I really wanted a Kreiger/Bartlein blank, but they had the criterion blank on hand when I called to talk about ordering and I didn’t want to wait 2 months for a blank to show up.  I have zero regrets not waiting… the criterion shoots lights out better than I do.

I’m using the adjustable gas key to tune it.  In hindsight, I recommend adjusting at the block.  The key method does work great for controlling the cycling and its simplicity is super reliable, but the action gets pretty damn filthy shooting suppressed because gas dumps unchecked into the upper.  I tuned gas to never have to mess with it; I swap buffers for shooting with/without a can.  It runs with the H2 buffer when unsuppressed and an XH buffer suppressed - it won’t cycle the XH buffer unsuppressed.

It consistently shoots tighter groups than my 18” Bergara Premier (lightweight VX6 scope).  However the Razor Gen2 topped M5E1 build is also about a full 6 POUNDS heavier and LOOONG (with its large action, PRS stock, 22” barrel, and 9” suppressor).  It’s a big bitch.

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The JP high pressure bolt is $199.

The features that differentiate are published right there:
https://jprifles.com/1.4.7_Bolt.php?menu_select=HPbolts

Today - there aren't HUGE advantages.  JP FP is .062" while Aero is .070".  Armalite uses .068" and standard DPMS pattern was .080".  Anything over .070" or any manufacturer with too much slop between FP and channel is going to result in the potential for pierced primers.  All it takes is a single pierced primer to ruin a FP if it erodes the tip.

Both will come with QPQ/Nitride finishes.

JP finish quality on their bolts and carriers is unparalleled IMHO.  JP made several modifications to reduce damage to the brass.  After owning many .308 semi automatic AR pattern rifles, I knew how bad the bolt/extractor/ejector can damage brass, and I was reloading, so these advancements and focus on reduction of impact to the brass was important to me.

Spending an additional $200 when building a near $2000 rifle, was insignificant.  Remember - match ammo is over $1.50 a shot.  Unless this is a safe queen, you spend WAY, WAY more in ammo or components than you ever do on the weapon itself.

Also, hyperfire’s Hypertouch Reflex and better triggers are phenomenal.

  Have CLE do a headspaced bolt with your barrel and use a aero carrier.
 Their barrels are definitely GTG

Never had an issue in a Aero 6.5 Creedmoor with a Aero BCG.

6mm Creedmoor was a whole different story. Falarak's pics were dead on.

I now have a JP bolt in one 6.5 and an RCA HP BCG in the other (which was the 6mm rebarrelled to 6.5). Even with that a good adjustable gas block and configurable buffer help.  

Yes you do. I went went a Toolcraft and quickly switched to JP high pressure because I was popping primers and starting charges.

Same, both in 6.5 Creedmoor.  I went with the Aero nitride BCG because it was the one that came with the bolt and firing pin hole size that was supposed to be appropriate for 6.5 CM.  This is back in 2017 so maybe they all do now.  Also, nitride makes cleaning an absolute breeze.

A JP high pressure bolt was a must for me. Was piercing small rifle primers with very low charge weights. Switched to JP and looked like regular 223 primers.

Wow. Just saw my own comment from weeks ago and said the same thing lolz