Build your own lightweight, match grade semi-auto 6.5 Creedmoor

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[ARCHIVED THREAD] - Build your own lightweight, match grade semi-auto 6.5 Creedmoor (Page 1 of 2)

Posted: 5/26/2017 10:40:31 PM EDT

I had a friend, who is an avid hunter, hand loader and long range target shooter, ask me if there was a way to build a lightweight, match grade, semi-auto 6.5 Creedmoor without
spending a fortune. The less expensive rifles weighed anywhere from 9.5 to more than 11 pounds for the bare rifle. After pondering the issue a while I decided to pursue a build using a small frame 308 as a host rifle. Buying as cheap as possible, saving weight with the small frame base and putting the money and weight into the barrel and outfitting with a Geissele trigger. Here is the result as a build video. Function and accuracy testing to follow....https://youtu.be/eweLAgf_55I

Posted: 5/26/2017 11:24:44 PM EDT

[#1]

Didn't know Rainier has GII barrels for 6.5 CM.

What are those flutes emerging from under the barrel extension?

Is that how DPMS does the Recon profile barrel?

What I've seen with the DPMS Panther Claw receiver insert is that even when they don't break the front pivot pin lug on uppers (which is pretty common), they gall the lug so that you might not get a tight receiver fit that existed before, if it did.

On AR10s and larger calibers in the AR15 even, I use way more torque than 35ft-lbs, at least 60ft-lbs.

For accuracy, you can bed the extension, but looks like you had a nice, snug fit requiring finessing to seat fully into the upper.

Looking foorward to seeing how it turns out for you.

These things need to be glassed with tough optics, or they will beat the scope internals up badly, so NF and higher end Vortex are all I use.

Posted: 5/27/2017 12:24:58 AM EDT

[#2]

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Quoted:
Didn't know Rainier has GII barrels for 6.5 CM.

What are those flutes emerging from under the barrel extension?

Is that how DPMS does the Recon profile barrel?

What I've seen with the DPMS Panther Claw receiver insert is that even when they don't break the front pivot pin lug on uppers (which is pretty common), they gall the lug so that you might not get a tight receiver fit that existed before, if it did.

On AR10s and larger calibers in the AR15 even, I use way more torque than 35ft-lbs, at least 60ft-lbs.

For accuracy, you can bed the extension, but looks like you had a nice, snug fit requiring finessing to seat fully into the upper.

Looking foorward to seeing how it turns out for you.

These things need to be glassed with tough optics, or they will beat the scope internals up badly, so NF and higher end Vortex are all I use.

View Quote

The flutes under the extension are part of the disign on both the take off and the Ranier G2 barrels.
The host is a DPMS G2MOE model
Have not had a problem with my receiver block causing a problem
Barrel nut torqued pretty tight
Yes, the fit of barrel was nice and tight
Using NF scope

Posted: 5/27/2017 1:59:35 AM EDT

[#3]

Looks like you'll have a sweet rifle once it passes function and accuracy testing.

Any plans for what loads you want to shoot?

There is a lot of great 6.5 CM ammo on the market from many vendors now.

Your set-up will make a great target, competition, and hunting rifle depending on how you configure it.

What mags are you looking at?

Posted: 5/27/2017 5:38:49 AM EDT

[#4]

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Quoted:
Looks like you'll have a sweet rifle once it passes function and accuracy testing.

Any plans for what loads you want to shoot?

There is a lot of great 6.5 CM ammo on the market from many vendors now.

Your set-up will make a great target, competition, and hunting rifle depending on how you configure it.

What mags are you looking at?

View Quote

I have some Hornady 143 gn to start with. My friend that started me thinking about this project hand loads and wants to work on developing his own loads.
I have Gen2 and Gen3 308 Magpuls and Lancers, as well as the factory magazine from DPMS.

Posted: 5/27/2017 10:11:54 AM EDT

[#5]

Ironically I am in the middle of doing almost the exact same build. I went with an 18 inch barrel and 16 inch slr handguard. Same trigger. A side note if anyone goes with an 18 full flute from rainer the gas block is .800 which threw me for a loop. The website says .750 but I would imagine they are going to up date it. I should have mine together in the next week or so and I'll throw some pics up.

Posted: 5/27/2017 11:00:01 AM EDT

[#6]

Michael, are you going to try the 6.5 Grendel in the short action AR? I just shot mine yesterday for the first time and I'm pleased with the rifle and the cartridge. It's more accurate than my 5.56 and delivers a noticeably greater punch. I was swinging steel at 250 yards with it yesterday and I'm confident that it will fill my needs for a deer/hog caliber in a light AR platform. The cheap Wolf ammo isn't bad and the cost is even lower than 5.56 too, and it cycled without problems in my carbine. The premium Hornady ammo did give me a couple of stovepipes which I believe are due to my action cycling too fast and I'm going to increase my buffer weights to (hopefully) eliminate that problem.

Posted: 5/27/2017 11:09:13 AM EDT

[#7]

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Michael, are you going to try the 6.5 Grendel in the short action AR? I just shot mine yesterday for the first time and I'm pleased with the rifle and the cartridge. It's more accurate than my 5.56 and delivers a noticeably greater punch. I was swinging steel at 250 yards with it yesterday and I'm confident that it will fill my needs for a deer/hog caliber in a light AR platform. The cheap Wolf ammo isn't bad and the cost is even lower than 5.56 too, and it cycled without problems in my carbine. The premium Hornady ammo did give me a couple of stovepipes which I believe are due to my action cycling too fast and I'm going to increase my buffer weights to (hopefully) eliminate that problem.

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I have not tried the 6.5 Grendel. I like to stockpile ammo so I try to limit the number of calibers I use. I picked 6.8 SPC instead. They are both good rounds but I can't do both. I am pleased with the 6.8 with a very short barrel for close work. The Creedmoor round was bought up by a friend that challenged me to see what I could come up with. He is an avid hunter,
hand loader and precision shooter.

Posted: 5/27/2017 11:23:10 AM EDT

[#8]

Nice video mbell. And very interesting build. I'm eager to see what kind of accuracy you get from that one.

Unfortunately, I don't see .260 barrels on Ranier's website. Too bad, I'm set up with .260 reloading gear and can't justify a new caliber.

Posted: 5/27/2017 6:07:52 PM EDT

[#9]

What diameter is the firing pin hole in the G II bolt face? I know the 6.5's tend to pierce primers unless you use a reduced diameter firing pin design like the JP or Aero.

Posted: 5/27/2017 6:15:46 PM EDT

[#10]

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What diameter is the firing pin hole in the G II bolt face? I know the 6.5's tend to pierce primers unless you use a reduced diameter firing pin design like the JP or Aero.

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What's this? Aero has a reduced diameter FP?

Off to google....

Posted: 5/27/2017 9:40:43 PM EDT

[#11]

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What's this? Aero has a reduced diameter FP?

Off to google....

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Yes. Their Phosphate and Nitride 308 bcg's have .070 diameter firing pins. Industry standard is .075 and JP is .065.

Their NIB 308 BCG is probably a re-badged toolcraft and comes with a .075 firing pin.

Posted: 5/27/2017 11:13:03 PM EDT

[#12]

There's an industry standard for firing pin diameter?

News to me. The ones I've measured are anywhere from .068" to .080" off the top of my head.

For a Creedmoor, .260 Rem, or even .308 pushing 175gr and up, I personally would want .068".

Posted: 5/27/2017 11:32:44 PM EDT

[#13]

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What diameter is the firing pin hole in the G II bolt face? I know the 6.5's tend to pierce primers unless you use a reduced diameter firing pin design like the JP or Aero.

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Hi Jay, I just went and measured. The firing pin hole in the bolt face is .085". The tip of the firing pin has a diameter of .0765". Are you thinking I need to change the firing pin?

Posted: 5/27/2017 11:58:25 PM EDT

[#14]

so the 308 bolt works fine with 6.5 creedmore?..does anyone know the optimum barrel length for creedmore?..lastly...it seems to me that once you put a scope and loaded mag on there you will be at 10.5-11lbs?

Posted: 5/28/2017 12:10:44 AM EDT

[#15]

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so the 308 bolt works fine with 6.5 creedmore?..does anyone know the optimum barrel length for creedmore?..lastly...it seems to me that once you put a scope and loaded mag on there you will be at 10.5-11lbs?

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308 bolt works with Creedmoor.
22"-24" gets you more velocity.
Once you put a scope and loaded mag on this build you will be up to 9.5-10 pounds. If you start with a 9.5 pound rifle or even an 11 pound gun, well......it only goes up from there. What ever you add for optics and ammo, you are adding to the base weight of the rifle. While hunting you could load only 5 rounds to keep the weight down.

Posted: 5/28/2017 12:21:06 AM EDT

[#16]

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308 bolt works with Creedmoor.
22"-24" gets you more velocity.
Once you put a scope and loaded mag on this build you will be up to 9.5-10 pounds. If you start with a 9.5 pound rifle or even an 11 pound gun, well......it only goes up from there. What ever you add for optics and ammo, you are adding to the base weight of the rifle. While hunting you could load only 5 rounds to keep the weight down.

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nice!..i didnt realize the bolt was the same!nice job and thanks for sharing.

Posted: 5/28/2017 1:24:32 AM EDT

[#17]

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nice!..i didnt realize the bolt was the same!nice job and thanks for sharing.

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Technically the bolt can be the same, but as mentioned in the thread you should be using a small firing pin diameter. Select your bolt for the 6.5 by going to JP's website and buying their High Pressure bolt.

Posted: 5/28/2017 6:33:36 AM EDT

[#18]

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Technically the bolt can be the same, but as mentioned in the thread you should be using a small firing pin diameter. Select your bolt for the 6.5 by going to JP's website and buying their High Pressure bolt.

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Quoted:

nice!..i didnt realize the bolt was the same!nice job and thanks for sharing.

Technically the bolt can be the same, but as mentioned in the thread you should be using a small firing pin diameter. Select your bolt for the 6.5 by going to JP's website and buying their High Pressure bolt.

The game plan right now is to test fire the rifle as built, once the new scope rings come in. I'll see if there are extraction issues and look carefully at the brass for pierced primers and other pressure signs.

Posted: 5/28/2017 1:44:35 PM EDT

[#19]

I will be under $2,000 and I'll be using 2A Xanthos upper/lower for weight savings. I estimate I'll be between 6-7lbs before optics/mag/ammo.

Posted: 5/28/2017 5:02:53 PM EDT

[#20]

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I will be under $2,000 and I'll be using 2A Xanthos upper/lower for weight savings. I estimate I'll be between 6-7lbs before optics/mag/ammo.

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That is a full size AR 10 receiver set. What bolt carrier group and barrel are you using. The standard BCG of AR-10s is a half a pound heavier than the small frame BCGs. What barrel and rail are you planning to use? Please post your parts list with weights so we can all learn. Also please include the prices of the parts. I got the entire host rifle for $925. The stripped receiver set you are using has a MSRP of $700. That is only $225 less than my entire host rifle. Let us know the specifics to get to your planned build. Thanks.

Posted: 5/28/2017 9:04:06 PM EDT

[#21]

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The game plan right now is to test fire the rifle as built, once the new scope rings come in. I'll see if there are extraction issues and look carefully at the brass for pierced primers and other pressure signs.

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I expect you will experience pierced primers with factory ammunition. I had to drop my Toolcraft bcg for an Aero in one of my builds.

Smaller diameter firing pin won't fix it, you need a smaller aperture in the bolt face.

Posted: 5/28/2017 9:33:29 PM EDT

[#22]

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I will be under $2,000 and I'll be using 2A Xanthos upper/lower for weight savings. I estimate I'll be between 6-7lbs before optics/mag/ammo.

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I held one of those at SHOT this year in 6.5 CM. I thought they wre playing tickery games with a display rifle sans the BCG.

Nope. It felt like paper, it was so light. It was easily a 6lb or less rifle with 22" barrel.

They had a lightweight carrier in it and pencil profile barrel.

Posted: 5/28/2017 9:46:23 PM EDT

[#23]

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That is a full size AR 10 receiver set. What bolt carrier group and barrel are you using. The standard BCG of AR-10s is a half a pound heavier than the small frame BCGs. What barrel and rail are you planning to use? Please post your parts list with weights so we can all learn. Also please include the prices of the parts. I got the entire host rifle for $925. The stripped receiver set you are using has a MSRP of $700. That is only $225 less than my entire host rifle. Let us know the specifics to get to your planned build. Thanks.

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I just finished a 2A Xanthos build. It weighs 7lb 2oz with an H3 buffer and a 18" 308 intermediate lightweight barrel. I could easily drop six to eight ounces if I switched to a carbine buffer, titanium gas block, titanium brake, and 2A 18" Creedmoor barrel. I'm at the same $2k price point. Building a 7lb AR10 isn't very hard.

Posted: 5/29/2017 7:19:17 AM EDT

[#24]

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I just finished a 2A Xanthos build. It weighs 7lb 2oz with an H3 buffer and a 18" 308 intermediate lightweight barrel. I could easily drop six to eight ounces if I switched to a carbine buffer, titanium gas block, titanium brake, and 2A 18" Creedmoor barrel. I'm at the same $2k price point. Building a 7lb AR10 isn't very hard.

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Well, I started with a 308 that only weighed 7 pounds, and it was only $925. So buying a 7 lb AR 10 for $900 isn't hard either. I could go with a lightweight barrel and save a pound but I am hoping for impressive accuracy...we'll see.

Posted: 5/29/2017 2:22:30 PM EDT

[#25]

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I expect you will experience pierced primers with factory ammunition. I had to drop my Toolcraft bcg for an Aero in one of my builds.

Smaller diameter firing pin won't fix it, you need a smaller aperture in the bolt face.

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This.

The factory G2 firing pin aperture will cause pierced primers in the 6.5 Creedmoor.

The titanium firing pin will erode on the first pierced primer and make the issue worse.

The flutes under the barrel extension are for gas venting in the event a case head fails.

Remington has a patent on the flutes.

Posted: 5/29/2017 3:15:45 PM EDT

[#26]

The 2A 20" 6.5CM barrel is 35 oz. I'm going with the 2A 15" rail as it's right at 10 oz. I'll probably get Aero BCG at 18oz...I know it's heavier than the V Seven, but I didn't want to go too crazy spending $500-600 on a BCG.

I have the BAD Sabertube "stock."

I was considering getting the JP barrel, but it weighs 3lbs and I didn't want to add that much weight for just the barrel. My build is more of a hunting rig, so weight is a huge consideration.

The Proof and Carbon Six carbon fiber barrels are still heavy and overpriced for what I want to do.

Posted: 5/29/2017 9:15:30 PM EDT

[#27]

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The game plan right now is to test fire the rifle as built, once the new scope rings come in. I'll see if there are extraction issues and look carefully at the brass for pierced primers and other pressure signs.

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Your chances of needing a smaller pin are 100% with the 6.5, we're just trying to save you the headache and money.

Posted: 5/30/2017 9:23:09 AM EDT

[#28]

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Your chances of needing a smaller pin are 100% with the 6.5, we're just trying to save you the headache and money.

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The barrel I am using has a proprietary length gas system, longer than rifle length. I was hoping that with the decreased dwell time and longer gas tube that some of the issues associated with pressure may be ameliorated.

Posted: 5/30/2017 9:39:39 AM EDT

[#29]

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The barrel I am using has a proprietary length gas system, longer than rifle length. I was hoping that with the decreased dwell time and longer gas tube that some of the issues associated with pressure may be ameliorated.

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I think the issue is more related to time spent under high pressure than when it unlocks. All my barrels are longer (24" and 26") so maybe with a little shorter barrel it won't act up. It would be interesting to know if a thicker primer material would solve the issue, but that would likely lead to needing stronger hammer springs for ignition.

Posted: 5/30/2017 9:54:51 AM EDT

[#30]

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I think the issue is more related to time spent under high pressure than when it unlocks. All my barrels are longer (24" and 26") so maybe with a little shorter barrel it won't act up. It would be interesting to know if a thicker primer material would solve the issue, but that would likely lead to needing stronger hammer springs for ignition.

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Gotcha. I will only shoot single shots and carefully inspect after each shot. I'll stop at the first sign of over pressure, and order the high pressure bolt. JP is the source, correct??

Posted: 5/30/2017 10:07:22 AM EDT

[#31]

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Gotcha. I will only shoot single shots and carefully inspect after each shot. I'll stop at the first sign of over pressure, and order the high pressure bolt. JP is the source, correct??

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JP does make high pressure bolts, but I don't believe they are compatible with a GII DPMS system.
http://jprifles.com/1.4.7_Bolt.php

The firearm blog has some pictures. Here is a gen 2 bolt next to a gen 1. The gen 1 is on the right.

http://www.thefirearmblog.com/blog/2015/10/15/big-3-east-dpms-g2-308/

Posted: 5/30/2017 10:25:38 AM EDT

[#32]

Would Aero Precision M5 upper and lower be considered Gen-1 or Gen-2? I am getting ready to build an AR-10 and this 6.5 CM project has me intrigued. I subscribed to your youtube channel and anxiously await the range test.

Posted: 5/30/2017 10:35:07 AM EDT

[#33]

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Would Aero Precision M5 upper and lower be considered Gen-1 or Gen-2? I am getting ready to build an AR-10 and this 6.5 CM project has me intrigued. I subscribed to your youtube channel and anxiously await the range test.

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M5 uppers and lowers are Gen 1. I used Aero M5 upper/lower combinations for both my 6.5 builds. One has a 24" Criterion barrel cut by Fulton Armory and the other is a 26" Krieger barrel. Both are heavy pigs with their long bull barrels and full frame receiver sets. I didn't get extended length gas systems, so I use rifle buffers with extra Tungsten weights along with adjustable gas systems to compensate. I used an Aero M5 BCG in the first one, then put a Toolcraft BCG in the second one. Then I went to checking individual dimensions and realized the Aero used the smaller firing pin diameter and corresponding hole. After a couple boxes with the Toolcraft BCG I pulled it out and ordered an Aero NIB BCG. When the Aero NIB BCG came in I found out it's nearly identical to the Toolcraft I already had (carrier profile and firing pin is the same as the Toolcraft and unlike the phosphate/nitride Aero BCG's). I exchanged it for a nitride Aero BCG which solved my pierced primer issue.

Posted: 5/30/2017 10:44:24 AM EDT

[#34]

I am thinking a 20" or 22" standard profile 6.5 barrel from Ballistic advantage. All else would be Aero Precision with Magpul furniture. This rifle could potentially replace my RRA AR-15 varmint rifle 223.

Posted: 5/30/2017 3:07:41 PM EDT

[#35]

I ended up ordering a Christensen Arms 20" CF 6.5CM from Optics Planet since the barrel was already on sale and I saved additional 10% from holiday sale.

I always wanted to try a carbon fiber barrel and I'm hoping it won't heat up as quickly as the 2A/Faxon barrel I was originally going to purchase.

Posted: 5/30/2017 4:16:39 PM EDT

[#36]

So what is needed to convert a DPMS GII to a 6.5 that operates reliably? Sounds like

1) 6.5CM specific bolt with smaller firing pin hole
2) Smaller firing pin
3) Barrel with extended gas
4) Adjustable gas block

Is that about right?

Im thinking about getting another while the rebate is going and buying a Rainier barrel for my first 6.5CM. A few posters here have talked me into trying it.

Posted: 5/30/2017 4:20:51 PM EDT

[#37]

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So what is needed to convert a DPMS GII to a 6.5 that operates reliably? Sounds like

1) 6.5CM specific bolt with smaller firing pin hole
2) Smaller firing pin
3) Barrel with extended gas
4) Adjustable gas block

Is that about right?

Im thinking about getting another while the rebate is going and buying a Rainier barrel for my first 6.5CM. A few posters here have talked me into trying it.

View Quote

Sounds about right. Possibly you could have the 308 bolt milled and bushed with a smaller hole, then get the firing pin turned down. I would probably go the Xanthos route.

Posted: 5/30/2017 4:39:53 PM EDT

[#38]

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Sounds about right. Possibly you could have the 308 bolt milled and bushed with a smaller hole, then get the firing pin turned down. I would probably go the Xanthos route.

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After handling both I wont go back to a large frame AR10. I may just wait for the Savage small-frame 6.5CMs to shake down.

Posted: 5/30/2017 4:43:06 PM EDT

[#39]

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After handling both I wont go back to a large frame AR10. I may just wait for the Savage small-frame 6.5CMs to shake down.

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I forgot about the new Savage. They seem like a good option.

Posted: 5/30/2017 6:02:43 PM EDT

[#40]

If that is a "later" GII, the bolt will have a smaller hole for the firing pin already.

Not sure about solving the issue with 6.5C, but it essentially solves the problem with cratered primers that all the "early" GII's exhibited (in .308 of course).

I cannot recall what the later diameter is, but can check if needed.

Posted: 5/30/2017 7:03:52 PM EDT

[#41]

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If that is a "later" GII, the bolt will have a smaller hole for the firing pin already.

Not sure about solving the issue with 6.5C, but it essentially solves the problem with cratered primers that all the "early" GII's exhibited (in .308 of course).

I cannot recall what the later diameter is, but can check if needed.

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I'm interested in the numbers.

Posted: 5/30/2017 10:25:09 PM EDT

[#42]

Unfortunately and/or apparently I've been misled, or something else changed.

The firing pin aperture in the later bolt I have is .080". The firing pin is .075".

Firing both the old and new bolts, the cratering problem was gone, but looking at my load/firing records, the loads I fired with the new bolt are all lower pressure, which may be part or all of the change I personally saw.

Or the earlier ones had an even larger aperture, the firing pin diameter changed, and/or a combination.

Posted: 5/30/2017 10:30:27 PM EDT

[#43]

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There's an industry standard for firing pin diameter?

News to me. The ones I've measured are anywhere from .068" to .080" off the top of my head.

For a Creedmoor, .260 Rem, or even .308 pushing 175gr and up, I personally would want .068".

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Some people who don't want to reduce their firing pin tip diameters claim there is.

Posted: 5/31/2017 9:08:01 AM EDT

[#44]

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Well, I started with a 308 that only weighed 7 pounds, and it was only $925. So buying a 7 lb AR 10 for $900 isn't hard either. I could go with a lightweight barrel and save a pound but I am hoping for impressive accuracy...we'll see.

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Quoted:

I just finished a 2A Xanthos build. It weighs 7lb 2oz with an H3 buffer and a 18" 308 intermediate lightweight barrel. I could easily drop six to eight ounces if I switched to a carbine buffer, titanium gas block, titanium brake, and 2A 18" Creedmoor barrel. I'm at the same $2k price point. Building a 7lb AR10 isn't very hard.

Well, I started with a 308 that only weighed 7 pounds, and it was only $925. So buying a 7 lb AR 10 for $900 isn't hard either. I could go with a lightweight barrel and save a pound but I am hoping for impressive accuracy...we'll see.

There is a lot of ways to skin this cat. Your video was well done and I like your presentation. If you get a chance please post a range report. Hopefully the G2 form factor gains more aftermarket support for people wanting to start from the ground up.

Thanks for taking the time to post this thread.

Posted: 6/1/2017 12:42:35 PM EDT

[#45]

Any range updates?

Posted: 6/1/2017 1:04:11 PM EDT

[#46]

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The flutes under the barrel extension are for gas venting in the event a case head fails.

Remington has a patent on the flutes.

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How are they doing that? Thread the shank and then run a ball mill or gear cutter over it?

Posted: 6/2/2017 9:10:58 PM EDT

[#47]

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Any range updates?

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Scope rings came in. I'll get the scope mounted tomorrow and get out first of next week to test fire and check accuracy, if there are no function/pressure issues.