6mm ARC vs 6.5 Grendel

SavageHunter11

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Well this thread has me thinking.

I basically designed my 24" 6.5 Grendel to be a long range steel shooter (600 yards is our longest shot). Shooting 107gr Sierra Match Kings BC G1 .455

The BC advantage of the 6mm bullets...95gr SMK BC G1 .515 or the Hornady 108 ELD-M BC G1 .536....

Would transforming my 24" Grendel to the 6mm ARC be as simple as a barrel swap?

They both use the same bolt?
Yes just a barrel swap and you should be good to go
 

CVCOBRA1

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The Grendel series 2, which is what most of the Grendel have been for years, has its own bolt. Bolt face is deeper. Not sure what the ARC has for a bolt face. Gas block and magazine should work for both if barrel length changes much you might need a gas tube.
 

CaptnC

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I went onto X-Caliber web page and walked through a barrel purchase. I can match my gas system to what I have now on the 24" Grendel barrel.

So if the bolt won't swap over I can buy a new bolt and save the G2 bolt I have for one of my other Grendel's.

Can 6.5 Grendel brass be used?

What about necking up 224 V brass?
 

SavageHunter11

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I went onto X-Caliber web page and walked through a barrel purchase. I can match my gas system to what I have now on the 24" Grendel barrel.

So if the bolt won't swap over I can buy a new bolt and save the G2 bolt I have for one of my other Grendel's.

Can 6.5 Grendel brass be used?

What about necking up 224 V brass?
You should be able to neck 6.5 brass down (I have not seen that confirmed however) but the 224 V is based on the 6.8SPC not the Grendel and you would not be able to neck that up.
 

CVCOBRA1

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Might be able to go over to the Grendel forum and get answers over there. I haven't been there for a while but I do know they were necking the 6.5's down to 6 and 22 as soon as the Grendels came out. Brass and load questions should be all over there.
 

CaptnC

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Screenshot_20200626-151349_Chrome.jpg


Well here the scoop on the bolt needing to be swapped.


The 224 V case looks so close to the 6.5 G that when I first started picking up brass for my Grendel's, I ended up with a hand full of 224 V cases.

I just picked up 40 224V Hornady cases at the range yesterday...on purpose this time....
 

CaptnC

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Might be able to go over to the Grendel forum and get answers over there. I haven't been there for a while but I do know they were necking the 6.5's down to 6 and 22 as soon as the Grendels came out. Brass and load questions should be all over there.
Those guys dont care too much for me over there. I am by no means a fan of short barrels (24" Grendel is more my style) and those cats over there make a lot of claims that a pistol length Grendel is a fine choice for a 1000 yard gun!

We go around and around about it...been a while since I've seen there too!
 

T3ninja

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I have a load with H322 and CFE tac. Accuracy is identical with about a 250 FPS advantage to h322...


This is with a Speer 70 tnt out of a 6 Grendel, (Predator) it’s pushing them with 322 at 3200
 

CaptnC

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I favor stainless barrels, but Brownells lists a Faxon 20" 5R CM but they have a Ballistic Advantage 24" SS barrel...

I really like 5R barrels, in my limited experience they can be faster...but I'm pretty sure the 24" would be the faster barrel.

Edit Post:
Must have been dreaming...went to X-Caliber to order the barrel...they don't chamber the 6mm ARC yet!
(Or do I spend an extra $50+ for the X-Caliber...24" 5R or the 3R...)

Unknown delivery regardless who it comes from????
 
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Wv shooter

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They like the Sig Fury because of the three piece lighter case design and its 80,000 lb pressure. Not sure how that is really going to hold up.
on the 6arc being adopted by DOD
Go to you tube and bring up hornady 6 mm ARC
 

Wv shooter

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Odin works is also offering 6 ARC barrels also I have two Odin barrels 6.5 Grendel and they are top of the line sub moa I have built many ar 15 with these barrels all have been great they are offering 21 inch that looks great Check them out at Odin works
 

HBoothe

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I hear most people are having a heck of a time getting the Valkyrie to shoot any kind of respectable groups. Sounds like it's a super finicky round to reload for. Full disclosure I have no experience with the round personally. If I am incorrect, someone please let me know.
I spent a year w the Valkyrie and I reload. While I only used it for hunting, I can say these things about the cartridge and long-range shooting and feel like I have some experience to back them up.

1) the twist rate on a lot of barrels, including some I have, was 1:8. Bullet stability calculators indicate that heavier bullets needed at least 1:7.7, and a few barrels were offered w 1:7.5. A guy I know owns a gun shop and had FITS getting a new build to group worth spit w 88-90gr bullets but grouped fantastic w 60 and 75gr. I told him 1:8 was too slow but he refused to listen. He swapped barrels and got it good enough to deliver to the customer...still makes me wonder about 1:8 twist, especially at the lower MV that cartridge has with the 88-90gr bullets.

2) high-for-weight/caliber BC is cute, but a heavier/larger high BC bullet will group better due to being less effected by wind/air currents.

I got sick of messing w carrying 60gr rounds for long-range (hunting...300-400yds w thermal) coyotes and 88gr for pigs. Too much hassle planning or changing mags. 64gr Nosler BSB seemed the answer. Hahaha. No. I finally got a Grendel and haven't looked back. 100gr ELD-M, 2,750FPS MV, 0.365 (or 0.385, can't recall for sure) BC. One bullet, one load for pigs, coyotes, and Bobcats at any range I'll shoot at.

Finally, relevant to the OP: I've not seen any MV (or load data yet) for the 6mm ARC other than some factory ammo info maybe. The Grendel will support 123gr ELD-M for sure (Hdy Black), but I think the max bullet weight for any available 6mm bullet will be 115gr. That's close. *If* you could find load data to show that the 115gr projectiles could be loaded in the 6mm ARC without killing powder room, then that might be a better choice as *maybe* the 115gr (or similar weight bullets) will have higher BC than the 123gr 0.264" bullets. But, the MV will have to be considered, too. Until load data is well documented, I think it will be hard to make an objective decision and choice.

FWIW, I dreamed and drooled about a 6mm cartridge for the AR-15 platform for a year (the whole time I was pushing marbles uphill w the Valkyrie) but the lack of SAAMI standard cartidges held me back. I reamed my own 24 Nosler barrel and bought a 6mm Predator (super nice guy to deal with selling/making those) but all after I'd chosen the Grendel as my daily cartridge. Now, w the 6mm ARC, a standardized cartridge, available...well, I found this post while seeking more info on it. And I've had a reamer on order from PTG for at least 6 weeks. That said to say this: I love the 6.5G...but the 6mm ARC could be what I've wanted all along.

HTH, YMMV, EIEIO.

--HC
 
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