SHORT-N-SASSY Wrote:Great idea ! But, let's go the route:

"We shoehorned a bigger cartridge into the gun. . . . Now, impose a Grendel geometry, and you are right at the tipping point." --- Bill Alexander < https://www.65grendel.com/forum/showthread.php?7287-why-would-bolt-break&p=75339&viewfull=1#post75339 >


< https://www.65grendel.com/forum/showthread.php?19499=Broken-bolts-thing-of-the-past&p=227010&viewfull=1post227010 >




< https://www.tactical-life.com/firearms/rifles/cmmg-mkw-anvil-rifle-6-5-grendel/ >

Let's challenge both designs:

Using the same barrel length, gas system setup and identical known hot loads, let's test a 6.5mm Grendel-chambered AR-15 against a 6.5mm Grendel-chambered CMMG Anvil: Increase the loads (noting respective velocity increases) with the express purpose of determining the breaking point of the Bolt lugs of the weaker design. Then, continue with the rifle that survived that test, to see how much increased velocity could be obtained. If some 200 fps additional velocity is possible, I think it would be fair to state that we'd opened-up a whole new ball game for an auto-loading 6.5mm Grendel --- the little cartridge that could.

< forum.snipershide.com/threads/anybody-have-a-6-5-grendel-bolt-rifle.109550/#post-2376269 >

Hornady.com Ammunition: 6.5 Creedmoor 140-grain BTHP American Gunner, Muzzle Velocity, 24" BBL, 2690 fps

a5blaster Wrote:awww heck some guy on barfcom broke a grendel bolt in his 6ar. Running what might be some very hot loads.

So y'all get ready there is probably going to be a 6 months parade of weak bolt post and claims of dangerous chamber's coming around agian.

Msalm Wrote:Anyone ever try and build a lightweight AR10 based rifle??? THAT'S the appeal of the Grendel on the AR15 frame... It doesn't do anything for me if you have to add a couple pounds with the ANVIL based rifle....might as well build off the 308 case then.

Msalm Wrote:Anyone ever try and build a lightweight AR10 based rifle??? THAT'S the appeal of the Grendel on the AR15 frame... It doesn't do anything for me if you have to add a couple pounds with the ANVIL based rifle....might as well build off the 308 case then.

Under the heading, What our sport shooting world needs is a lightweight 6.5mm Grendel CMMG MkW ANVIL rifle, I today sent the following email to Jeff Overstreet, CMMG Inc. :

And, the Fims Manufacturing Small Frame AR10 rifle: 7.25 lbs ---



< http://www.gunsholstersandgear.com/shot-show-2019/ >

SHORT-N-SASSY Wrote:And, the Fims Manufacturing Small Frame AR10 rifle: 7.25 lbs ---



< http://www.gunsholstersandgear.com/shot-show-2019/ >

A5BLASTER Wrote:The only way to get the cmmg grendels to come in at ar15 weight standings is this.

Replace all the internal parts that you can with either titanuim or aluminum parts. Remill the bcg to be really lowmass or have a custom shop build you a aluminum or titanium bcg in a lowmass configuation.

Then take the lower and mill out the side plates of the mag area.

Take the upper and have a custom shop mill in some slots along the length of the upper to drop weight their. Or have a custom shop mill you a lowmass style upper to replace the cmmg one with.

Then loss the buffer and spring it comes with throw in the very best lowmass buffer and spring system made. Slap a adjustable gas block on the barrel after having the barrel re profiled down too .600 and the gas block area re profiled to .625 and then put on a titanuim adjustable gas block and a titanuim flash hider.

Throw on the most stripped down basic stock they make and add a 10 round mag half loaded top it off with a red dot and bam a 7 pound cmmg grendel rifle.

Are you could I don't know safe a bunch of money buy a chronagrah and work up sane loads and never break a bolt.

I have a few irons on the fire right now but I'm gathering materials to do a bolt breakage test.

Handloads will be set at 55k. And we going to see how many rounds it takes to break it.

LRRPF52 Wrote:If you're using a bolt with the mass of the LR-308 and CMMG Anvil bolt, you will depart from the 3:1 rule of carrier mass-to-bolt mass if reduce the carrier weight.

That can/will result in sluggish unlocking unless you gas it hard, and you still run into the issue of sluggish cyclic rate in the initial rearward inertia.

This is one of the problems with the Remington Model 740 and 7400 semi-auto hunting rifles.

The CMMG Anvil in Grendel also has a bit more mass than even a .308 bolt because of the reduced bolt face width for a narrower cartridge.

Compound that with the fact that you have 10gr less of case capacity and lower working pressure than .308 Win., and you are really setting up for needing to make some gas system changes if you want to have a reliable action.

I think for a 6mm AR, the CMMG Anvil makes a lot of sense where you aren't worried about bolt thrust, since the 6mm AR has more bolt thrust than 6.5 Grendel due to the bottle neck effect on back pressure.

Kswhitetails Wrote:A5 - in the ar15, the overall variation and departure from the ideal of the ratio is much less pronounced than it would be for the Anvil. There's obviously a pretty wide envelope for the 15, considering all the variations that so many folks find relatively easy ways to make work, especially considering how many amateurs are out there putting together our Lego sets. 3.2-2.8:1 vs 6.5:1-ish etx...

I'm no metallurgist. And I'm making a fool of myself asking; but why hasn't anyone made a super-steel bolt that would do what we're asking? Surely there's some kind of solution without re-inventing the entire wheel? Ti bolts with the proper heat treat, or Inconel blend? I'm sure it has something to do with the strength to flexibility ratio...

Under the heading, CMMG POWER BOLT, I today sent the following email-request to CMMG Tech Support ---

I today received this Reply:

- - - - - - - - - - - -

And, my response:



< https://www.targetsportsusa.com/prime-annunition-6-5-remington-saum-4s-ammo-142-grain-otm-match-plus-7528240020-p-109362.aspx >