Need help on building AR-10 for 6.5 Creedmoor or converting cheap .308 to 6.5

[HFicalore]

Okay so I currently have a Remington 700 5R Gen 2 with a Vortex Strike Eagle 4X24-50 for long range. It has a few other add on’s such as Timeny 510 trigger, lancer viper muzzle brake, etc. I shoot Hornady ELD-M 147 gr bullets. That’s my primary long range gun. My next upgrade will be in letting the stock to take magpul pmag box mags.
So to keep everything matching I wanted to make an AR-10 16” 6.5 creedmoor with a 1X6-24 Vortex Strike Eagle (may keep it simple and stay with irons) That way mags and ammo were all interchangeable in a SHTF moment and not having to lug even more gear to and from the range just for plinking. I’m having difficulty finding exactly what I want in an AR-10 from stores. Keep in mind that I have no intention of ever shooting this rifle past 400 +/- yardsHowever most shots would be within 200 yards. This new AR-10 would replace my AR-15 in 5.56.
I work at my local Sheriff’s Office and plan on going to Sniper School as soon as everything is open again. #corona. So cost is a factor because the Po-Po doesn’t make a lot of money! The AR-10 will not be a Designated Marksman Rifle or shooting competition. It will do exactly what you would expect a dirt cheap AR-15 to do. Close to midrange targets, quick transition between targets, and able to take a beating. Side note neither of the rifles will be used through my department only as my personal toys.

So my question is would it be better to.....

1) Buy a used/cheap completed AR-10 in 6.5 Creedmoor with a 20” barrel and an eleven degree reamer and cut the barrel myself to 16”. (My worry here is rifling for a 20” barrel being in a 16” barrel after I cut it and not knowing how that will affect spin drift, POI at 100 yards compared to my 700, and anything else that I’m not knowledgeable enough to know about)

2) Buy a used/cheap completed AR-10 in .308 and a new bolt assembly with a Faxon Firearms 16” Big Gunner 5R barrel and just do a barrel swap (the 5R rifling would match my Remmy 700). If this is the best option would it have to be a 16” .308 from the start so gas tubes matched without any smithing? (I’m leaning towards this one just because I know the rifling will be the same and the 2 rifles will shoot fairly consistent compared side by side within certain yardages unless, I’m hopelessly lost) yes I know to allow some variations because one is semi and one is bolt and they are 2 different lengths which affects velocity and blah blah blah.

3)Buy a cheap AR-10 lower and just slap a 6.5 Creedmoor upper on it.

4) Build an AR-10 16” 6.5 creedmoor from scratch.

I’m not worried about threaded (however I do like them for flash suppressors and muzzle brakes) because I have no intention of running a can until they require no tax stamp and they’re not as heavily regulated as they are (if it ever happens). I’m looking for the cheapest option because of money mixed with the easiest option because I’m no expert. I’m willing to learn and willing to do work on the rifle to make it work, however would prefer not to destroy it in the process of making it. Any input is appreciated because this will be my first ever AR-10. If building it is the best easiest/cheapest option it will be my first full build so any input on that would be great as well.
My end goal would be to have 2 rifles that shoot the exact same ammo, take the exact same mags, ready at all times, regardless if it’s mags strapped to my Tac Vest in the rural areas, in the woods, or in the city streets or if it’s mags just thrown in a bag or in the backseat for a nice trip to the range. So if it’s a fun day to the range I’m good and if it’s SHTF I’m good. The AR-10 i’d like, in theory, to be accurate out to 400+/- yards if needed in extreme circumstances (even though I’ll probably never stretch it that far in practice)
I can’t stress enough that while I know 6.5 isn’t the perfect point man/entry gun or close to midrange caliber I would, in a perfect world, use my 700 for 100 yards and more and use the AR-10 at shots within that range.

Sorry for such a long post. This is my first one so I wanted to make sure I hit all the points I needed to. I’d prefer not to discuss different set ups because I don’t care if 2 extra inches will give me a million extra yards because I already have the long range gun. This gun will be used for anything from point blank/no aim shooting to 100 yards and in and as a grab and go gun. However if there is some major factor I’m overlooking and there is some huge “tacti-cool” advantage of 16” to any other size I’d love to hear it. I personally would love it if I found a rifle that fit the 16” 6.5 Creedmoor criteria I set above already completed in a store for under $1500. Thanks in advance for any and all input.

 

[357Max]

@HFicalore

Welcome to the hide.

You didn't mention barrel length on the rem 700, I'll assume 16". It sounds like what your after is a bit of a unicorn.

For your questions:
1. No! if you chop 4" off the barrel gas system will not work. Even a cheap piston driven like Adams arms would need dwell time for the piston to work.

2. Could work........but 16" 6.5 will has higher gas system pressure so you'll probably wind up spending money on adjustable gas block, heavy buffer, buffer spring. then you'll still have the larger firing pin of the 308 that tends to crater primers with a 6.5. Might not be a problem with a 16" barrel, but it's a gamble.

3. AR 10/DPMS/LR25 don't have a mill spec. It's real easy to wind up with an upper that doesn't match contour of lower & I don't just mean Armalight vs DPMS. You could assemble a functional combo that would just look fugly. Then you still have to get gas system sorted, $$ & frustration can add up pretty quick.

4. Build from scratch is a fun challenge, but don't go in thinking you'll be saving money & be prepared to spend range trips getting it sorted. If you want to go this route & can see yourself building more in the future, I'd highly recommend taking a good AR armorers class. Be honest with yourself on cost, you will buy some parts x 2 cause they didn't work, you will need $ for tools such as head space guage & upper action wrench, vice block torque wrench etc.

The above is my honest opinion with regards to what your after.
Here comes the But.
In any of the above scenarios I don't honestly think you'll get a reliable 16" AR 10 6.5 C for $1500. If it were me I'd seriously consider keeping the 5.56 and selling the 700 to up your AR 10 budget. Inside 600 yards there is nothing the large AR wouldn't do as good as a 700 if it's quality rifle. In any of the above scenarios I don't honestly think you'll get a reliable 16" AR 10 6.5 C for $1500

Check out the every day sniper podcast episode 255 With Game warden discussing how their department upgraded to a very similar AR 10 as what your after.
I think theirs were 14.5" barrels & 308.
https://theeverydaysniper.podbean.c...per-episode-255-john-nores-hidden-war-author/

For new rifles I'd take a good look at:
POF Revolution
LMT (V1 tactical is a good vender to buy from).
LWRC Reaper

FYI - Wilson Combat has exactly what your after with the Recon Tactical but it's $3K @ under 8 lbs is pretty damn good for a large frame.

Lastly Since your LE, some of the vendors mentioned above will likely offer an LE discount. I would check with them.

 

[E. Bryant]

Step 1: Order Larue Ultimate Upper kit with 18" 6.5 CM barrel for $1200 https://www.larue.com/products/larue-ultimate-7-62-260-6-5cm-upper-kit/

Step 2: Order Larue billet lower for $300 https://www.larue.com/products/larue-billet-lowers/

Assuming that you have Larue build the upper, you will simply need to assemble the lower, put the two halves together, and you'll have a pretty nice large-frame AR for $1500.

 

[357Max]

@E. Bryant - Yep Larue completely slipped my mind this morning. Great suggestion!
From a bang for the buck standpoint the ultimate upper deal would be hard to beat. You could also get there suppressor with the deal.

 

[HFicalore]

Thank you guys so much for your input. My 700 is the 22” heavy barrel, fluted, threaded, and bedded. I plan on using my 700 for hunting and playing on the range out to 2000 yards, if I ever get that good. The AR-10 would be a fun gun for the most part. I may sling some lead down range out to 600-800 yards for $hits and giggles thought most shots would be well within 200 yards. However I just want it to operate the way you would expect an AR-15 in case there was a SHTF moment. I love interchangeable calibers and mags. Also idk if I mentioned this in my original post but the $1500 would just be for upper and lower preferably. I wouldn’t hesitate to go to $2000 or even $2500 for a well built AR-10 not including mags, ammo, optics, etc. again thanks for all the input!

 

[HFicalore]

So this DB10 6.5 C wouldn’t work if I just took a hack saw to the last 4 inches, recrowned it, and paid my local gunsmith $100 to redo the threading? That gun is around $1150. Can you explain to me what it would all require to make it work like that please. I know I’m asking questions as if I was a novice but hey, we all have to start somewhere.

 

[Landon4]

You put in your post about the 700 and the ar-10 taking the same mags, I don’t believe that will work as the 700 should use ai style mags, atleast mine do, and the ar will use the regular ar-10 pmags.

 

[rpoL98]

my limited experience, Faxon is one of the barrel mfrs that uses the Armalite AR-10 gas tube lengths for their large-frame DPMS-pattern AR-308 barrels. about a 3/8" difference. There's 2 standards used for AR-308's, just something to watch out for, if you're buying a 308 AR-10 to convert to 6.5CM with a barrel swap. Not a bad thing, just one of the pitfalls of the no AR-380 standards. For instance, Criterion 308/6.5CM uses AR-15 length gas tubes.

just an FYI.

 

[gunsnjeeps]

Rock River Arms has 20 inch 6.5 Creedmoor for $1525, 24" is $1500. I see shorter barrels.

No irons, so you'd need a scope. PSA has had Vortex 1-6 and 1-8 scopes with mounts advertised lately.

About $2000 ready to go but 20". I'm not sure, but I think they do LEO pricing. I know Vortex does if you contact them.

 

[357Max]

So this DB10 6.5 C wouldn’t work if I just took a hack saw to the last 4 inches, recrowned it, and paid my local gunsmith $100 to redo the threading? That gun is around $1150. Can you explain to me what it would all require to make it work like that please. I know I’m asking questions as if I was a novice but hey, we all have to start somewhere.

I answered this in my first post (post #2) item #1. That's a solid answer, but.........
I'll have to admit I'd not considered starting with a Diamond back. Since they have a mid length gas system on a 20" barreled 6.5 (WTF) it could technically work. Perfect choice for taking a hacksaw to
Mid gas would work with a 16" barrel. Might have to screw around with adding adjustable gas block & or change buffer weight.

Not my cup of Tea & not something I'd consider a SHTF gun, but hey it could work.

 

[RyanScott]

Rifle is more appropriate for a 16” 6.5. Perhaps longer.

 

[Rumblestrip]

Just about everything is out of stock but you could also look at PWS.

 

[shax2lex]

Buy a Seekins Precision coupon from someone off The Hide and go buy one of their rifles already put together. It will be a shooter, it’s fully ambidextrous, and they make good stuff. I’ve made this recommendation before and I’ll keep saying it. Go look it up and I think you’ll be happy. It’s a very cost effective and accurate option. It’s a proven rifle.

 

[Oldsnakeindagrass]

If its mil-spec get a .308 upper assy from PSA.

 

[Oldsnakeindagrass]

Okay so I currently have a Remington 700 5R Gen 2 with a Vortex Strike Eagle 4X24-50 for long range. It has a few other add on’s such as Timeny 510 trigger, lancer viper muzzle brake, etc. I shoot Hornady ELD-M 147 gr bullets. That’s my primary long range gun. My next upgrade will be in letting the stock to take magpul pmag box mags.
So to keep everything matching I wanted to make an AR-10 16” 6.5 creedmoor with a 1X6-24 Vortex Strike Eagle (may keep it simple and stay with irons) That way mags and ammo were all interchangeable in a SHTF moment and not having to lug even more gear to and from the range just for plinking. I’m having difficulty finding exactly what I want in an AR-10 from stores. Keep in mind that I have no intention of ever shooting this rifle past 400 +/- yardsHowever most shots would be within 200 yards. This new AR-10 would replace my AR-15 in 5.56.
I work at my local Sheriff’s Office and plan on going to Sniper School as soon as everything is open again. #corona. So cost is a factor because the Po-Po doesn’t make a lot of money! The AR-10 will not be a Designated Marksman Rifle or shooting competition. It will do exactly what you would expect a dirt cheap AR-15 to do. Close to midrange targets, quick transition between targets, and able to take a beating. Side note neither of the rifles will be used through my department only as my personal toys.

So my question is would it be better to.....

1) Buy a used/cheap completed AR-10 in 6.5 Creedmoor with a 20” barrel and an eleven degree reamer and cut the barrel myself to 16”. (My worry here is rifling for a 20” barrel being in a 16” barrel after I cut it and not knowing how that will affect spin drift, POI at 100 yards compared to my 700, and anything else that I’m not knowledgeable enough to know about)

2) Buy a used/cheap completed AR-10 in .308 and a new bolt assembly with a Faxon Firearms 16” Big Gunner 5R barrel and just do a barrel swap (the 5R rifling would match my Remmy 700). If this is the best option would it have to be a 16” .308 from the start so gas tubes matched without any smithing? (I’m leaning towards this one just because I know the rifling will be the same and the 2 rifles will shoot fairly consistent compared side by side within certain yardages unless, I’m hopelessly lost) yes I know to allow some variations because one is semi and one is bolt and they are 2 different lengths which affects velocity and blah blah blah.

3)Buy a cheap AR-10 lower and just slap a 6.5 Creedmoor upper on it.

4) Build an AR-10 16” 6.5 creedmoor from scratch.

I’m not worried about threaded (however I do like them for flash suppressors and muzzle brakes) because I have no intention of running a can until they require no tax stamp and they’re not as heavily regulated as they are (if it ever happens). I’m looking for the cheapest option because of money mixed with the easiest option because I’m no expert. I’m willing to learn and willing to do work on the rifle to make it work, however would prefer not to destroy it in the process of making it. Any input is appreciated because this will be my first ever AR-10. If building it is the best easiest/cheapest option it will be my first full build so any input on that would be great as well.
My end goal would be to have 2 rifles that shoot the exact same ammo, take the exact same mags, ready at all times, regardless if it’s mags strapped to my Tac Vest in the rural areas, in the woods, or in the city streets or if it’s mags just thrown in a bag or in the backseat for a nice trip to the range. So if it’s a fun day to the range I’m good and if it’s SHTF I’m good. The AR-10 i’d like, in theory, to be accurate out to 400+/- yards if needed in extreme circumstances (even though I’ll probably never stretch it that far in practice)
I can’t stress enough that while I know 6.5 isn’t the perfect point man/entry gun or close to midrange caliber I would, in a perfect world, use my 700 for 100 yards and more and use the AR-10 at shots within that range.

Sorry for such a long post. This is my first one so I wanted to make sure I hit all the points I needed to. I’d prefer not to discuss different set ups because I don’t care if 2 extra inches will give me a million extra yards because I already have the long range gun. This gun will be used for anything from point blank/no aim shooting to 100 yards and in and as a grab and go gun. However if there is some major factor I’m overlooking and there is some huge “tacti-cool” advantage of 16” to any other size I’d love to hear it. I personally would love it if I found a rifle that fit the 16” 6.5 Creedmoor criteria I set above already completed in a store for under $1500. Thanks in advance for any and all input.

100yds is not a long shot unless its a pistol. The Creedmoor will far out shoot that .308, especially in a late model 700. An off the shelf PSA PA65 will be ringing the plate at 1670 yd mark on a regular basis and that's a semi auto 20" ss hbar in 6.5 creedmoor. If you need affordable large mass downrange shooting go with .300 winmag... maybe in a tikka or a savage. Not a lot of $$ there. Other than that, the 6.5 creedmoor is a helluva round. Of course you can always spend the money to turn that late model remington into a good precision rifle. I used to use an M-24 w/ redfield 10X with pretty good results

 

[celltech]

I have built 3 AR10's in .308 and 6.5 that were right at $1200 each and 8 lbs. All built around Aero Precision M5 bodies, Faxon barrels, LaRue 2 stage triggers, Brownell BCGs. Find the parts on sale, use Mil/LEO discounts, etc and you can keep the costs "down", but an AR10 will never be a cheap rifle build.

 

[Oldsnakeindagrass]

Everyone has their own opinion and I respect that, but I use my blue discount for my handguns. A gen2 or 3 PSA out of the box is made with very high quality parts and range from 640.00 to 1000.00. One of the few A10s you can unbox at the range and ping the mile marker