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Broken 6mmAR Bolt
#1
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.
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#2
LMAO
I better check my spare BCG's.
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#3
Without seeing his velocities and loads I can’t say he was pushing the limits, but most of us do. I was pushing it in my .224 Grendel but it’s shelved for now, and for sale BTW!! If you push the pressure limits in these guns, especially if gas and recoil system isn’t tuned, broken bolts are bound to occur. Like shooting a bunch of high pressure 5.56 ammo in a .223 chamber. Somethings gotta give.
Member since 2011, data lost in last hack attack
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#4
I can hear the 6.8 and Valkrie guys tuning up already...
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#5
Popeye212 Wrote:I can hear the 6.8 and Valkrie guys tuning up already...

for a rousing chorus of Boo-birds no doubt!
"Down the floor, out the door, Go Brandon Go!!!!!"
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#6
ricsmall Wrote:Without seeing his velocities and loads I can’t say he was pushing the limits, but most of us do. I was pushing it in my .224 Grendel but it’s shelved for now, and for sale BTW!! If you push the pressure limits in these guns, especially if gas and recoil system isn’t tuned, broken bolts are bound to occur. Like shooting a bunch of high pressure 5.56 ammo in a .223 chamber. Somethings gotta give.

He says 28.5 grains of target under a 105 something didn't really pay attention to what bullet he said it was.

He hasn't replied back to the post yet. So it could just be a troll trying to start mess. Seems how that site is.
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#7
A5BLASTER Wrote:He says 28.5 grains of target under a 105 something didn't really pay attention to what bullet he said it was.

He hasn't replied back to the post yet. So it could just be a troll trying to start mess. Seems how that site is.

A5B:

That is at the high end of the load data but is not an overload.

LR55
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#8
LR1955 Wrote:A5B:

That is at the high end of the load data but is not an overload.

LR55

I figured it was but don't know much about the 6ar. And just realized I fat fingered my post it's varget not target lmao.
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#9
28.5 grains target FlagRolleyes under a 105 something Flag :confused: and didn't really pay attention to what bullet it was Flag Sad. Smell test Fail. Has a faint aroma of Tuna though
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#10
Popeye212 Wrote:28.5 grains target FlagRolleyes under a 105 something Flag :confused: and didn't really pay attention to what bullet it was Flag Sad. Smell test Fail. Has a faint aroma of Tuna though

I said I didn't really pay attention to all the load details. I didn't say he didn't pay attention.

And I fat fingered my other post it is varget not target.

I just thought I would bring it to the horde's attention so they could know where the more then likely to come parade of broken bolt dangerous chamber post that seem to grow around post like these.

He did post that this bolt is the upper' s second bolt to break and that the upper is used he bought off the original owner.

The bolt he just broke is a JP bolt. A member of barfcom said his load is probably around 63k and the the load that the first owner was running that broke the first bolt was around 75k according too quickload.
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#11
I just googled and found several 6mm 105's: Barnes, Berger, Nosler, Lapua, or Hornady 105's.
"Down the floor, out the door, Go Brandon Go!!!!!"
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#12
grayfox Wrote:I just googled and found several 6mm 105's: Barnes, Berger, Nosler, Lapua, or Hornady 105's.

He posted it was 105 nosler cc in his loads.
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#13
A5BLASTER Wrote:I said I didn't really pay attention to all the load details. I didn't say he didn't pay attention.

And I fat fingered my other post it is varget not target.

I just thought I would bring it to the horde's attention so they could know where the more then likely to come parade of broken bolt dangerous chamber post that seem to grow around post like these.

He did post that this bolt is the upper' s second bolt to break and that the upper is used he bought off the original owner.

The bolt he just broke is a JP bolt. A member of barfcom said his load is probably around 63k and the the load that the first owner was running that broke the first bolt was around 75k according too quickload.

My bad I thought you were quoting HIM
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#14
Popeye212 Wrote:My bad I thought you were quoting HIM

It's all good. Just wanted to clarify what I was meaning is all.
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#15
Here's the thread in question: https://www.ar15.com/forums/ar-15/6-5Gre...21-739665/

From what I can tell, it seems well handled and the consensus appears to be more along the lines of "you overloaded your round", than anything negative about Grendel. Not really sure where the angst against AR15.com comes from. It does have its share of jerks and fools and at times I question why I even go there - but then, find me a forum that doesn't.
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#16
It's getting to the point that I've been thinking about how I can increase my shoot schedule to purposely try to break bolts just to see where it will happen.

I've lost count of how many different Grendel AR15s I've been shooting over the years now, with everything from RLGS 24", 22", and 20", to 18" MLGS x many, 16" MLGS, and now 12" CLGS suppressed.

12" CLGS suppressed should be the hardest on the bolt since the gas system is so much closer to the chamber, resulting in much higher port pressures.

Maybe drop in the Franklin Armory Binary trigger and stack pallets of Wolf steel case, but for what?
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#17
LRRPF52 Wrote:....
Maybe drop in the Franklin Armory Binary trigger and stack pallets of Wolf steel case, but for what?

For the Best TIME EVVAAAHHH!!!
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#18
lazyengineer Wrote:For the Best TIME EVVAAAHHH!!!

I lol-ed.
Nothing kills the incentive of men faster than a healthy sense of entitlement. Nothing kills entitlement faster than a healthy sense of achievement.
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#19
LRRPF52 Wrote:It's getting to the point that I've been thinking about how I can increase my shoot schedule to purpsoely try to break bolts just to see where it will happen.

I've lost count of how many different Grendel AR15s I've been shooting over the years now, with everything from RLGS 24", 22", and 20", to 18" MLGS x many, 16" MLGS, and now 12" CLGS suppressed.

12" CLGS suppressed should be the hardest on the bolt since the gas system is so much closer to the chamber, resulting in much higher port pressures.

Maybe drop in the Franklin Armory Binary trigger and stack pallets of Wolf steel case, but for what?

It would be best if someone other then you did it. Because if you do it, it will just be said that you cooked the results somehow.
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#20
LRRPF52 Wrote:. . . to purpsoely try to break bolts just to see where it will happen. . . .

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/showthre...#post75339 >

[Image: LR55.png]
< https://www.65grendel.com/forum/showthre...post227010 >

[Image: big-bolt.png]

[Image: CMMG-Power-Bolt.png]
< https://www.tactical-life.com/firearms/r...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.
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