New Member, just getting started with my 308AR build... Lots of questions and the info here is amazing!

[Wilburbean]

Hello, 

I'm building my first 308AR.  My buddy purchased the Juggernaut Tactical(JT) AR jig for 80% builds.  I picked up a JT 308AR 80% lower and just completed the milling and side drilling.  I need to do some filing to remove the rough edges but it turned out well.  I had much better equipment than when I did my Polymer80 AR-15 about 5 yrs ago.

I was looking to build a 6.5 Creedmoor upper and found lots of complete uppers for sale online.  Poking around on this site, it's clear that compatibility is an issue for many builders.  I was then going to buy a completed upper from JT but they only sell a .308 upper.  I was then worried about getting a complete upper from another site and have it be not compatible with the JT.  JT is a DPMS lower but they state that they are not compatible with Aero Precision DPMS uppers.  I built my Polymer80 AR with an Aero Precision upper and had no issues but the AR-15 world benefits from the mil-spec. 

So... 

1. Should I buy the JT upper and then build from there or are there known complete upper manufacturers that are JT compatible?  Many vendors sell complete 6.5 Creedmoor uppers and I'd rather go that direction but not if it creates more problems than it solves.  JT does not sell a Creedmoor upper or barrel.  
2. I'm assuming that if I do 6.5 Creedmoor that I need a barrel(probably 22''), gas block and rifle length gas tube.  If my understanding is correct, getting an adjustable gas block will help in tuning the gun to run using a standard 308 BCG.  Reading all I can but piecing together snippets of information.  

Did some searches on this site and would love to find a 308 upper/lower compatibility chart by manufacturer.  Probably a ton of work that would obsolete immediately.

I sent a list of questions to JT BTW.  They don't have a phone number listed.  I would prefer to talk to someone and get their two cents.  

I appreciate all the comments, questions and face palms.  

 

[shooterrex]

The Bear Creek uppers fit my Bushmaster/DPMS pattern lower just fine. 6.5  Creedmoor and 308 is just a different barrel.

For the price I'd get the Bear Creek complete upper and then switch everything to the other folks upper if it didn't fit. Barrel, BCG, rail, and gas system will move over easy.

Unless I'm just building a bench gun the 22" is a lot of extra length and weight to mess with.

My 16" Creedmoor does 850 yds no problem.

Just my thoughts.

[shooterrex]

Oh and welcome from KY.

[Wilburbean]

Just now, shooterrex said:

The Bear Creek uppers fit my Bushmaster/DPMS pattern lower just fine. 6.5  Creedmoor and 308 is just a different barrel.

For the price I'd get the Bear Creek complete upper and then switch everything to the other folks upper if it didn't fit. Barrel, BCG, rail, and gas system will move over easy.

Unless I'm just building a bench gun the 22" is a lot of extra length and weight to mess with.

My 16" Creedmoor does 850 yds no problem.

Just my thoughts.

Thanks for the insight!  The Bear Creek complete uppers are very affordable.  I like your thinking there.

Interesting on your 16in barrel, I think i was thinking more bench PRS than AR.  

[98Z5V]

7 hours ago, Wilburbean said:

Interesting on your 16in barrel, I think i was thinking more bench PRS than AR.  

What is your goal for the gun - what do you want it to do for you?  That's the most important question. 

[Wilburbean]

9 hours ago, 98Z5V said:

What is your goal for the gun - what do you want it to do for you?  That's the most important question. 

Great question and probably the most important one.  I will not be using it any real competitions.  PRS is all bolt action and I don't want to spend that kind of coin. 

I might use it for my next hog hunting expedition (we go to Louisiana each year to hunt hogs from air boats in the Mississippi delta). 

I think I had some hang over from doing a PRS build from an old Mauser action bleeding into the discovery and allure of complete 6.5 CM uppers from Bear Creek. 

Now that I type this I think that shooting metal and paper targets with friends and an occasional hog hunt would be it's main purpose.  I'm thinking this means that .308 makes more sense, especially in the ammo/cost area.

[JBMatt]

Welcome from AZ.  

If you're going the 6.5 route, this is the recommended BCG for that.  I have it in my 6.5 build and have had much less trouble than guys that run 308 BCG's.  It has a small diameter firing pin which greatly helps in not blowing holes in primers due to higher pressures in the 6.5.  But, get an extra firing pin or 2 just to have on hand.

https://www.armorally.com/shop/toolcraft-6-5-creedmoor-double-ejector-bcg/

https://www.armorally.com/shop/toolcraft-ar10-small-diameter-firing-pin/

[98Z5V]

On 6/1/2022 at 7:39 AM, Wilburbean said:

Now that I type this I think that shooting metal and paper targets with friends and an occasional hog hunt would be it's main purpose.  I'm thinking this means that .308 makes more sense, especially in the ammo/cost area.

Good answer for the purpose of the rifle - usually catches people off guard when you ask them, then you get an answer back that they want it to do everything...   You thought out the purpose for the gun. 

If you'll never go over 600 yards, I'd just run a 16" barrel with midlength gas.  No need for any more barrel than that.  If you'll go a little longer, like out to 850, maybe an 18" barrel.  FOr whatever distance you'll shoot, there's no reason at all to go over an 18" barrel - not for what you'll use the gun for.   My $0.02 on it.