Grendel hybrid

[Mopardoctor]

Has anyone done a large frame AR Grendel and are the parts compatible with the 65.5 Grendel?

Mopar Doctor

[A5BLASTER]

Do you mean grendel but in the ar10 platform?

[Mopardoctor]

Yes. The longer magazine could allow more COAL.

[LRRPF52]

2.500" COL would open up things for shooting longer projectiles with optimum base placement relative to the neck-shoulder junction.

CMMG has the Anvil, which is basically an LR-308 receiver set and BCG cut short, using AR15 magazines and Magwell.

The Magwell and other mechanical engineering considerations are the constraints, followed by mags.

Look in the wildcat section here on the forum, as we've had this discussion for as long as the forum has been around.

[A5BLASTER]

2.500" COL would open up things for shooting longer projectiles with optimum base placement relative to the neck-shoulder junction.

CMMG has the Anvil, which is basically an LR-308 receiver set and BCG cut short, using AR15 magazines and Magwell.

The Magwell and other mechanical engineering considerations are the constraints, followed by mags.

Look in the wildcat section here on the forum, as we've had this discussion for as long as the forum has been around.

Does the LWRC 68 reciver set not allow a longer cartridge length?

[FRB6.5]

Uses AR15 magazines so no. They basically shortened an AR10 upper and BCG to give more "beef" for things like .458 SOCOM.

Edit: nvm I was talking about the Anvil. The SIX8 is something different. Given magpul still won't make 6.5 Grendel mags I have a feeling is still likely a no.

[A5BLASTER]

Uses AR15 magazines so no. They basically shortened an AR10 upper and BCG to give more "beef" for things like .458 SOCOM.

Edit: nvm I was talking about the Anvil. The SIX8 is something different. Given magpul still won't make 6.5 Grendel mags I have a feeling is still likely a no.

Grendel can run out of pmags and it always works out of 6.8 mags as well, so I'm sure a lil reverse engineering can be done.

What I was asking is looking at pics of the receivers and mags it looks like the 68 system has a longer internal length then the standard ar15 lower.

[FRB6.5]

looks like cutting them will get you to 2.368"
https://68forums.com/forums/showthread.p...ew-mag-mod

A cut PRI will give 2.36" in a standard AR15 lower
https://www.cavitybackbullets.com/produc...od-mag.htm

[LRRPF52]

Does the LWRC 68 reciver set not allow a longer cartridge length?

The Six8 mags still have limited COL, but are fatter so that they could make a magazine out of polymer that would stack the 6.8 cases correctly and feed, rather than trying to fit 30rd mags in the AR15 receiver set with steel mags.

That requires a new, fatter Magwell receiver set for the Six8, but there aren't any real COL advantages with the Six8 PMAGs. They allow up to 2.295" COL before they start to seize up with case taper stacking/COL considerations for a box mag.

2.400"-2.500" COL is what the Grendel needs if you want a long-throat wildcat shooting longer bullets.

Problem with Grendel and the longer, heavier pills is drop, which is why the 6mm AR and the new developments with the .257" bore make more sense for me personally.

[A5BLASTER]

The Six8 mags still have limited COL, but are fatter so that they could make a magazine out of polymer that would stack the 6.8 cases correctly and feed, rather than trying to fit 30rd mags in the AR15 receiver set with steel mags.

That requires a new, fatter Magwell receiver set for the Six8, but there aren't any real COL advantages with the Six8 PMAGs. They allow up to 2.295" COL before they start to seize up with case taper stacking/COL considerations for a box mag.

2.400"-2.500" COL is what the Grendel needs if you want a long-throat wildcat shooting longer bullets.

Problem with Grendel and the longer, heavier pills is drop, which is why the 6mm AR and the new developments with the .257" bore make more sense for me personally.

Yes sir I understand that.

What I'm saying is I seen a pic of the two recovers next too each other and the 68 lower is indeed longer in the interior room.

So if you was to window the mag I belive a longer coal then in a ar15 lower could be used.

Now if someone was to make metal mags for that 68 lower then it would be something worth chasing I'm sure.

[LRRPF52]

The Six8 PMAGs have more thickness on the front and rear walls of the mag, so I can see why LWRC would want to add magazine well length to accommodate the additional thickness of the PMAG.

The Army Ordnance guys had one dude who wanted to improve on the .222 Rem SCHV concept back when several cartridges were still being hammered out.

Initial problems with the .224" 68gr projectiles retaining energy for steel helmet perforation had 2 different suggestions for dealing with that requirement:

* Stoner's approach - add a boat tail to the bullet to help it retain energy, and run higher pressure with more case capacity to create faster mv and better impact velocity. They blew the shoulder forward and launched a 55gr bullet as fast as they could with the new experimental .222 Remington Special case.

* Minority individual engineer suggestion - Take the 25 Remington case, neck it down to .224, re-design the receivers, bolt, and mags for a new cartridge with more case capacity, slightly fatter, longer bullets with higher BC.

Stoner and ArmaLite saw this as an attempt to slow-roll the AR15 so that it would die in constant engineering changes from the Army, effectively killing the AR15 in its infancy. It's only so often that stars align with the right people in the right places to allow innovation to move forward and root itself to gain widespread market success.

6.5 Grendel fights against that reality with its performance and the welcome home of the widespread AR15 receiver set and parts availability.

Any attempts to move forward with something new will require another alignment of stars.

[A5BLASTER]

The Six8 PMAGs have more thickness on the front and rear walls of the mag, so I can see why LWRC would want to add magazine well length to accommodate the additional thickness of the PMAG.

The Army Ordnance guys had one dude who wanted to improve on the .222 Rem SCHV concept back when several cartridges were still being hammered out.

Initial problems with the .224" 68gr projectiles retaining energy for steel helmet perforation had 2 different suggestions for dealing with that requirement:

* Stoner's approach - add a boat tail to the bullet to help it retain energy, and run higher pressure with more case capacity to create faster mv and better impact velocity. They blew the shoulder forward and launched a 55gr bullet as fast as they could with the new experimental .222 Remington Special case.

* Minority individual engineer suggestion - Take the 25 Remington case, neck it down to .224, re-design the receivers, bolt, and mags for a new cartridge with more case capacity, slightly fatter, longer bullets with higher BC.

Stoner and ArmaLite saw this as an attempt to slow-roll the AR15 so that it would die in constant engineering changes from the Army, effectively killing the AR15 in its infancy. It's only so often that stars align with the right people in the right places to allow innovation to move forward and root itself to gain widespread market success.

6.5 Grendel fights against that reality with its performance and the welcome home of the widespread AR15 receiver set and parts availability.

Any attempts to move forward with something new will require another alignment of stars.

Ok so going off the fact we know the 68 lower is longer. In my aero lower with a windowed cpd mag I can load and run loads at 2.355 and they feed perfectly.

So most likely a windowed 68 polymer mag would put loads close too if not just past 2.400.

Think I might order up a 20 round 68 pmag too do a lil hands on testing.

[Kilco]

6mm Grendel is what the world needs.

I'm nipping on the heels of my 243/6 Creed with equal barrel lengths with my 6 grendel, and I'm using over 10 grains less powder with the 6 grendel.

Using my 20" 6 grendel pushing a Sierra 90gr game changer with a b.c over .5 2920 fps my family killed 3 whitetail in impressive fashion at ranges out to 320 yards. That's big boy performance from a small frame AR burning 28.5gr of powder. I dont know of another cartridge this efficient.

I've been down the large frame AR wildcat rabbit hole more than once, and if it's not a magazine issue, it's a cycling issue or a pressure issue.

My point is, the 6 Grendel is right on the heels of "AR10" performance as is, let alone a hybrid small/large frame AR.

I am still blown away one of the big companies hasn't standardized the 6 Grendel yet and the Valkyrie design was chosen by federal instead..