6.52 Grendl on AR 15 lower

[Bassam Altwal]

Hi All, New here.

Shot out to Ghostrider for telling me about this group.

I started building an AR 15 (my second), yet, now I'm thinking of using a 6.5 upper, they say it fit perfectly on the the lower AR 15, my question is, the magazine also fit including the release? Or do I need to modify? I really don't want to modify my lower.

Thanks

 

[MEHavey]

You sure you don't mean 6.5 GRENDEL ?

 

[Bassam Altwal]

You sure you don't mean 6.5 GRENDEL ?

Yes, sorry

 

[MEHavey]

The GRENDEL is specifically designed to fit/function on a standard AR-15 lower.
Literally drop-in and shoot.

 

[1stmarine]

Yes they fit in the regular AR15 lower. Order a couple of 6.5 Grendel magazines.
Also make sure you order the bolt with the barrel head-spaced for it. The dimensions are not standardized and bolts form different makers might result in problems.
There are now quality bolts being made that are a lot stronger than the original along with good quality barrels. This is a preventive measure to avoid premature bolt failures so invest a bit more in quality parts.
Also check out the 6.5 LBC (Les Baers) that is 100% compatible chamber with the 6.5 Grendel but IMO a better throat design towards maximizing accuracy.
Nothing huge but so you know they are also available out there.

 

[Bassam Altwal]

Great answers, thanks guys

 

[Bassam Altwal]

Yes they fit in the regular AR15 lower. Order a couple of 6.5 Grendel magazines.
Also make sure you order the bolt with the barrel head-spaced for it. The dimensions are not standardized and bolts form different makers might result in problems.
There are now quality bolts being made that are a lot stronger than the original along with good quality barrels. This is a preventive measure to avoid premature bolt failures so invest a bit more in quality parts.
Also check out the 6.5 LBC (Les Baers) that is 100% compatible chamber with the 6.5 Grendel but IMO a better throat design towards maximizing accuracy.
Nothing huge but so you know they are also available out there.

Any suggestions of a vendor?

 

[1stmarine]

I got the fist one from Alexander arms and the barrel was great. The bolt broke eventually and decided to rebarrel to a more potent 6.5mmBR.
The 2nd one I got from AR15performance.com and the barrel and bolt are working perfectly. they Beefed up the bolts and had a nice price on nitrocarburized (melonite) 5R barrels.
I also used young manufacturing bolts for other wildcats and so far so good. Also a beefed up bolt design but these guys do not sell barrels, I think.

 

[barnbwt]

The dimensions are not standardized and bolts form different makers might result in problems.

Two standards; one uses 7.62x39 bolts, one uses Grendel bolts. The x39 variant came about when Grendel bolts were hard to come by.

 

[1stmarine]

Two standards; one uses 7.62x39 bolts, one uses Grendel bolts. The x39 variant came about when Grendel bolts were hard to come by.

Within the Grendel there are bolts that headspace differently between brands that are made by different companies (some OEM) and there is no standard on these like mil-spec.
The .135 vs. .125 bolt recess has nothing to do with it. The critical dimension is from the bolt face to the back of the lug. That is where you find variations between makers selling "Grendel bolts".
So the best advice we can give people is to buy the bolts matched with the barrel or at least from makers that have been confirmed by the manufacturer to have the proper dimensions.
Otherwise after mixing parts from different mills there is the risk of getting a less than desirable chamber even if the no go gauge passes the test.
I was never faced with this issue because I buy parts from the same manufacturer but I learned from others having problems with headspace as a result of the different dimensions.

Edit: The same issue can happen with 7.62x39 bolts btw. Less obvious because the round is pretty forgiving and most people shoot steel and toss it away.

 

[Bassam Altwal]

Within the Grendel there are bolts that headspace differently between brands that are made by different companies (some OEM) and there is no standard on these like mil-spec.
The .135 vs. .125 bolt recess has nothing to do with it. The critical dimension is from the bolt face to the back of the lug. That is where you find variations between makers selling "Grendel bolts".
So the best advice we can give people is to buy the bolts matched with the barrel or at least from makers that have been confirmed by the manufacturer to have the proper dimensions.
Otherwise after mixing parts from different mills there is the risk of getting a less than desirable chamber even if the no go gauge passes the test.
I was never faced with this issue because I buy parts from the same manufacturer but I learned from others having problems with headspace as a result of the different dimensions.

Edit: The same issue can happen with 7.62x39 bolts btw. Less obvious because the round is pretty forgiving and most people shoot steel and toss it away.

Thanks, I'm planning to buy a complete upper from one source, I think that way I avoid the issue.

 

[MEHavey]

Bill Alexander is first class-- both personally & professionally. 'Can't go wrong.

That said, the early bolt lug cracks largely came from handloaders running thing up to 223 pressures/55KSI(and higher). The Grendel deliberately operates at 45-49KSI.

 

[Double Naught Spy]

Any suggestions of a vendor?

ASC http://www.ammosc.com/6-5-grendel/

 

[MEHavey]

BTW: Barring the long 500-grainers, a standard 223 magazine works w/ GRENDEL cartridges just fine.
(Try it)

 

[barnbwt]

That said, the early bolt lug cracks largely came from handloaders running thing up to 223 pressures/55KSI(and higher). The Grendel deliberately operates at 45-49KSI.

People were trying to get Creedmoor performance from the little Grendel. No free lunch.

The bolt face depth issue, I understand, has to do with extractor engagement. Grendel's 220 Russian parent case has a thicker rim than 223, so in order to avoid thinning the extractor claw to fit over it (as is done on the shallow 7.62x39 bolts) the face was set back an additional .01" or so, and the chamber depth reduced accordingly. Partially due to shortage of Grendel bolts during the Panic, and partly due to certain companies falling out with Alexander Arms, the low-demand x39 bolts (few good AR mag options for the x39 back the ) were pressed into Grendel service in conjunction with a shallower chamber. LBC fell out with Alexander over reamer licensing (specs, not money; Alexander was trying to maintain solid control over the geometry of his round, Les Baer wanted to modify it from his spec, so Alexander refused to let them call it 6.5 Grendel)

A mismatch results in the bolt not going fully into battery in one case, and somewhat excessive in another.

TCB

 

[MEHavey]

The other issue w/ "garage-put-together" guns was that people put a standard 223 firing into GRENDEL bolts.... resulting in punctured primers from the bolt faces being recessed per Barnwp's note above.

Simple fix (30sec with a file) but ya gotta realize what you've got in your your hands.

 

[1stmarine]

hi @barnbwt
I got the upper from Bill Alexander short after it came out on sale. The barrel was awesome and the accuracy great.

The rounds were all accuracy loads well below the maximum pressures advertised for the cartrige but eventually the bolt failed.
If you go to the Grendel forums you will see this happened to several shooters even without pumping up the loads.
Many people didn't break bolts but perhaps were not shooting that much and leaving the cartridge for hunting or occasional use.
I think in later generations this has been resolved at least to a degree with stronger bolts but the original bolts had a shorter service life.

We understand now why when we look at AR15performance and Young manufacturing bolts for example with increased radius at the lugs,
9310 alloy and proper heat treatments.
I have been pushing these 9310 bolts with some wildcats to see if I could brake them on purpose but I couldn't, I mean before stretching
the brass too much beyond a comfortable level. I am not going beyond 60Kpsi anyway.

AR15performance is now offering a 750 XD (Extreme Duty) that is even stronger with proprietary barrel extension so it will never break
no matter if one pushes the strong lapua brass to 60K psi.
One more thing, Bill Alexander is a great guy no doubt. The original load data for the grendel when it came out it was a bit optimistic
and after some discussions and corresponding notes and threads in the grendel forums he was kind to adjust those to more realistic levels.

IMO the round never had to "compete" with anything due to its specific purpose. We knew it was a slow round but with much better bullets
in terms of ballistics performance. Plus, like the 6.8SPCII, both have the most versatile loads are with 90gr-100gr that can shoot a lot
faster and flatter and put more output in the 800yards. In either caliber is more than plenty for 99.9% of the practical uses out-there.

When I decided I wanted more from the AR15 I invested in the 6.5mmBR and others vs. abusing the 6.5Grendel.

Everyone should understand the limitations of a round but as we all know the marketing, sales people and tacticool evangelists can
use all the power of the internet to misinform and push for impossible feats. Look how far the whisper has gone this way.
In the process people will break bolts and ruin brass w/o getting the promised results but many w/o even knowing it because
the average guy does not invest time in understanding the world of ballistics.

 

[Double Naught Spy]

BTW: Barring the long 500-grainers, a standard 223 magazine works w/ GRENDEL cartridges just fine.
(Try it)

Tried it with GI mags, Pmags, and Thermold. NO GO. It certainly didn't work with the Beta drums either.

 

[MEHavey]

Funny.... works with every 223 mag I have -- GI, Colt, Armelite, and PMag.
Every one....