Any 7.5" or close in size Grendel barrels out there?

Seems like this round could cycle subs and with supers out perform 14.5" barreled 5.56.

Got any velocity data for a 7.5" Grendel? Finding it hard to believe that short of a barrel beats the terminal ballistics of a 14.5" 556 with M193.  Granted that's kinda comparing apples to oranges putting a fragmenting m193 up against say an expanding hornady 123SST 

Linkage to some info

Thanks for the link. It appears the 7.5" could be a great option.

It appears the 123 gr. 6.5 Grendel out of a 7.5" barrel will have the same energy as the 14.5" barreled 5.56 with the m193.

A 10.5" Grendel has more energy at the muzzle than a 20" 5.56 NATO, with way higher BCs, and will out-perform the 16.3" and 20" AK or SKS shooting the exact same bullet weight from the same basic case size.

Is there any more data on 7.5"? I know it's a great long distance round but it also seems like a great SBR round as well.

I think I will do a Grendel pistol for a shop demo if I can find a reasonably priced barrel. I think Grendel is the future of ARs and it only helps that ammo and parts are competitively priced.

Maybe I will do a 10.5" upper to use with my Omega. Any recommendations on low to mid price barrels?

You should try a 9" then report back

I am thinking about getting this-
http://ballisticadvantage.com/18-inch-65-grendel-spr-rifle-ss-premium-barrel.html
and having ADCO cut to 7.5" and put pistol gas length. What do you think? @LRRPF52

Precision Firearms has them.  

I would start there rather than chop a perfectly good barrel.

Do you think 7.5" barrel would be too short? Any idea on it's capabilities?

I'm rather interested in 10.5" myself,  but you might just want to confirm with SilencerCo, what is their minimum length/pressure threshold?  Per the .pdf manual, they state: "The Omega is rated down to 10" barrels for .223 Remington/5.56 NATO, 16" barrels for .308 Winchester/7.62 NATO, and 20” barrels for .300 Win Mag."

Not that 6.5G is a super high-pressure round, but I have a feeling they have done TONS of testing in various calibers, and might even be able to direct you the optimal length based on their experience and testing.

TAG!

I have Dead Air Sandman cans so no minimum length issues.
I am looking at making a PDW that could also shoot some distance and possibly hunt with. Sort of a do everything.
The 5.56 is too damn loud and worthless in such short barrels. 300blk is limited on distance and no cheap bulk to plink with.

A 7.5" with the 123gr SST would limit your expansion threshold down to 125yds, if the mv is 2000fps.

125yds 1800fps 885ft-lbs

It would be plenty for 2-legged TGTs within CQB and down-the-street range.

If overall length reduction is the goal, I personally went with the shortest suppressor on the market, or one of them, which is also the lightest.

That gives me more barrel length and performance.

12" + TBAC Ultra 5 = ~16.5" overall barrel/suppressor length.

If your can is 7" to 9", I can see why one might want to go shorter on the pipe, but you don't really need to unless you're married to one can.

With the 12" barrel and factory ammo at 2275fps, I still have expansion to over 275yds with 123gr SST, and over 400yds with 123gr AMAX or ELD-M.

TBAC Ultra 5 is 7.6 ounces BTW.

So I guess I was incorrect in my thoughts. Seems like a 5.5" 300 blackout would be a better candidate.

For what?

5.5" barrel on any bottleneck cartridge with BLK case capacity is going to have sub-par performance at best, more like a pistol.

With the 6.5" barreled 300blk people are regularly dropping hogs at 220. Must be expanding.

What forum you seeing that on? Most hog hunting forums I frequent have a less than stellar opinion of the 300blk on hogs and I myself have moved from 300blk to 6.8 and 308.  I mean if they are scoring head/neck CNS shots maybe.  

Honestly I saw better terminal effects from m193 out of a 14.5" on hogs than with 300blk. Which is why posted here in the first place since I was having trouble wrapping my head around the first post.  

This guy has some of the best 300 BLK hunting videos out there.  He almost always uses 10.5" or longer barrels.

Look at the penetration depth, which is to be expected with that slow mv.

I've never heard of anyone saying that. Starting with the 6.5", that seems crazy short and I've never heard of that size for 300blk. Doesn't mean it isn't out there, but it's not a common size, and dropping hogs at 200+ with that setup is a stretch.

The user coregon can verify this for you. It's happening with many folks out there. I think both the 300blk and 6.5G have much more potential than what we currently have.

I had a 10.5, 9 and 8.5 300 blk uppers and currently kept the 8.5.  it's always suppressed (handguard is 12")  

I was going to sell it and get a 7.5 but decided to do 6.5 Grendel instead.  Still debating between 10.5 and 12.5 for it.  It will be suppressed.  
I have four sbr'd AR15 (5.56, 300, .22, 9mm) lowers and will repurpose one of them for the 6.5 and build a pistol lower for whichever.  
Maybe the .22 since it's got a folding stock that never gets unfolded.

What about an 8.5" barrel for your Grendel build?

I'm still looking at velocity charts online with the different barrel lengths.
I doubt I would ever shoot this past 300 yards (longest range I have access to).

I'm comfortable with the way my 8.5" 300blk with 762SDN6 handles and thought about that for the 6.5, but I'm still debating what length would best serve me.
Not counting the 22 or 9mm, my other ARs are a 10.5" 5.56 and 18" 5.56.  I wanted something new to reach out a little further without having to go to .308.

Not sure if it helps, but my 12.5” 6.5 Grendel with Omega is my favorite rifle right now.

How short do you really need?

Need, LOL. This isn't about needs

But seriously, I was thinking a PDW sized gun that can still reach out. I have seen handloaded subs cycle. Seems like a do all type of PDW.

I don't know what the quality of this 7.5" Grendel barrel is but any takers?

That's my plan. 12.5.  how does it sound suppressed?
I'm using my only .30 cal can, 762SDN6.
Hoping to get a smaller direct thread suppressor next to leave on all the time.

It’s super quiet. I love it. Seems way quieter then any 556 guns my friend bring along. I do have a custom made endcap in 6.5 for my Omega tho.

There is a 65Grendel site out there, currently a group buy on for Faxon 12" barrel, 155 plus shipping.

This isn't the best site for straight up Grendel info..

12"GB

Can you tell a difference with the custom endcap? Where did you get it?

I would imaging taking a 5.56 end cap and drilling it to size. I do know with a 5.56 sized end cap on one of my 308 sized cans there is a noticeable difference as in quieter or just maybe deeper.

Here's a 10.5" it looks like suppressed, auto:

That was awesome

I am going to just go ahead and try out a 7.5" barrelled Grendel with a Dead Air Sandman S. It's calling to me for some reason

Do you have any recommendations of a specific 7.5" barrel? What twist and port size? Also, would 5/8x24 be good threading for the barrel?

TIA

< Trolling removed - F >

A Dead Air Stellite welded core sounds like a good solution to the blast and pressure of a 7.5" barrel.  I would call and ask Dead Air for confirmation before committing to that pipe length just to be sure.

< Stay on topic - F >

I'm all ears as to why you think 6.8 would be better.

6.8 was designed from the start to perform in 16" or shorter barrels.  6.5G was not.  Can you have a 6.5G SBR...sure.  However, you are getting pretty far outside the 6.5G's strengh...and getting into the area where the 6.8 shines.

There are quite a number of 300 WTF shooters, hog guides included, that switched to 6.8 for improved terminal performance.  To thoses that have watched all 3 variants since inception, this is common knowledge.

Pick the right tool for the job.

Grendel is the cartridge to beat in SBRs.

It may have been designed to be a great white tail cartridge for the AR15, but that doesn't mean it doesn't maximize the capability of an SBR any less-quite the contrary.

I even compared it to one of the mongo-nuclear hand loads people are doing in 6.8, and it still beat it at 200yds.  This is keeping the Grendel within 50,000psi chamber pressure, and running the 6.8 in excess of its limitations in the AR15, Grendel still beat it.

It's just that not many people have bought, tested, and chronographed a lot of Grendel SBR loads because they were told over and over they needed 20"-24" barrels to realize any potential from the cartridge.

Mack Machowicz (RIP) did a really nice review on it in 14.5" M4 configuration many years ago, but people vested in 6.8 repeated that Grendel is not good in SBRs here, so people believed them.

David Fortier did some initial testing with 12.5" Grendel many years ago, to include chronographing various loads and even in sub-freezing temps, and it did really well, to the point that he prefers it over his 16", 18" and 24" Grendels for shooting LaRue targets at distance.

There is nothing in the AR15 that has the versatility of steel case ammo, the 123gr SST, and the 129gr ABLR premium hunting load.

It just doesn't exist.  The steel case practice ammo is enough to convince most, but there aren't any factory loads for any of the other intermediate cartridges that do what most of the 6.5 Grendel loads will.  Some will come close, but nothing exceeds the downrange performance.

You're telling me it's all common knowledge yet I cannot find it anywhere.
6.5G strengths are long range yet there is nothing I can find that tells me it wouldn't be good for a 7.5" barrel. ETA: It may not be at it's best but it seems like it would be better than the others.
Is there a chart out there that compares the 6.8 directly to the 6.5G that we all regularly see with the 300BO and the 5.56 that compares all the barrel lengths from very short to long?

I would like the idea of a PDW and an 18" barreled rifle in 6.5G. I have seen subsonic 6.5G rounds cycle in an AR15. Same round for everything. Why not?

ETA2: I am not looking for subsonic, it would just be a nice bonus.

So a quick search on other sites shows-

6.8 with a 7.5" barrel was tested and showed average 2035fps and

6.5G with a 7.5" barrel was tested and showed average 2040fps.

So it seems pretty equal to me. Wouldn't the 6.8 start dropping like the 300BO at distance while the 6.5G keeps on trucking much further?

And this is all there seems to be out there on the 7.5" barrels.

Biggest problem I've run into over the years is the goal post moving for 6.8 SPC.

The moment you source even hot-loaded SSA ammunition that was pushed to pressures in excess of SAAMI MAP, you get told you're cherry-picking the data to make 6.8 underperform.

Then you accept one of the nuclear hand loads that exceeds SAAMI MAP by an even larger factor, compare it against a factory 6.5 Grendel load that still beats it from the exact same barrel length, and your family name is trashed.

Then you look at actual factory ammo muzzle velocities, and they're about the same as 6.5 Grendel for the same barrel length and bullet weight, so you scratch your head and wonder what it is people are doing, outside of repeating what they've been told, or pushing pressures well outside of what is safe in the AR15.  

There's a fundamental lack of understanding of how the AR15 works, how pressure containment works, industry standards, and basic applied physics with most of the arguments I've seen in favor of 6.8 being made online, contrasted with a few members who are very reasonable and accept the cartridge with its capabilities and limitations for what it is.

It's worse than the 9mm vs .45 ACP debate, with guys who have dedicated entire pages of their business websites to trashing my name and character even.  I've never seen anything like it before outside of politics.

A 16" 6.8 will push a factory 120gr SST anywhere from 2450-2520fps.  I've seen many posts showing those chronograph numbers, which match Hornady's published speed for that load from a 16" barrel, as well as their reloading data.

A 16" 6.8 will push the Wilson Combat 95gr Barnes TTSX load to 2600fps per Wilson Combat's own data, and this makes perfect sense with the other data out there.

A 20" 6.8 tested to SPC II as stated in Accurate Powder's own recent data will push an 85gr Barnes TSX HP to 3020fps at 54,997psi using AA2200.

Then in the same breath, you'll see guys telling you a 12.5" 6.8 SPC II safely pushes that exact same bullet to 2975fps.  Sure it will, if you're brave enough.

A more reasonable speed from a 12.5" 6.8 SPC II with an 85gr Barnes is 2780fps.

But even if I take that moronic, unsafe, throw caution to the wind and match a barrel that is almost twice as long speed.....

It still doesn't have as much energy or speed at 200yds as a safely-loaded 12.5" 6.5 Grendel with an 86gr solid bullet.  Why?

Because the 86gr solid in the Grendel has a BC of .374, and the stubby little 85gr Barnes TSX has a BC of .246, so it sheds energy rapidly within the first 100yds, making all that muzzle velocity really impressive online to people who don't run the numbers out to 200yds, but not really doing you a lot of favors.

When I point this out, instead of accepting the data, I'm told that I'm cherry-picking to make the Grendel look better than it actually is, even though I used the fastest brave reloader data there is that can't be safe in the AR15 in 6.8's favor.

When you run the reasonable numbers, which can be confirmed with multiple tested industry sources across the powder and bullet manufacturers, the 2780fps 85gr TSX loses its tiny edge in speed within the first 25yds over the 86gr 6.5mm HV even at 2724fps mv.  Never get into a reloading competition when both cases have the same capacity, and one of them exceeds your BCs by such margins.

So with all that said, does the 7.5" Grendel out perform the 7.5" 6.8?

I can objectively see the goal post moving with the 6.8 world. Lots of crazy behind it and the same with the 300BO. What I see with the Grendel is everyone using it for long range. That's great and I plan to do so also. I want a PDW with it too because why not. A PDW that can make hits out to 600 yards sounds enticing.

If I had the equipment set up and ready to go, I'd load some 6.5G, borrow a 7.5G barrel, and chrono it, but I don't.  Out of that short of a barrel, I don't know how effective any rifle round is really going to be.  My CZ Scorpion SBR has about that length of barrel, and it's a 9mm.

The only 7.5" Grendel data I'm aware of is from Precision Firearms chronograph results they posted.

If I take the 7.5" data and run it through a Powley computer that is calibrated for 6.5 Grendel, here is what I get for different bullets:

86gr 2442 fps
90gr 2393 fps
95gr 2336 fps
100gr 2275 fps


To me, 7.5" seems short.  You're cutting off a lot of expansion potential from most of the cartridges for hunting outside of the ABLR, but if you don't care much about expansion and just want to hit things, it will have supersonic reach to 700yds with a 123gr SMK or Scenar, and I used the averaged G7 drag profile, not the static close range G1 profile for the ballistics calculator.

123gr SMK 2000fps, G7 BC .260

600yds 1212 8.3 mils drop 2.1 mils drift
700yds 1113 10.8 mils drop 2.5 mils drift

With 129gr ABLR for hunting assuming a 1950fps mv:

125yds 1786fps 913 ft-lbs
300yds 1569fps 705 ft-lbs

It will actually expand out to 500yds reliably, with over 500 ft-lbs, but I wouldn't recommend it for most shooters.  200 and in with that bullet will work fine.

I personally chose 12" for my PDW build, but I have a 5" TBAC Ti can waiting for it.

Thanks for the response. 40" of drop at 700yds from a 7.5" barrelled Grendel sounds awesome.

With the suppressor I want to use with a 7.5" barrel would make OAL right about the same as your 12" with just a F/H on it and I do have a Sandman K in jail so I could be even shorter.

For H/D it sounds great and can plink to 500yds.

I understand all SBR's, excluding pistol rounds, are handicapped but it seems like the Grendel would be the least handicapped in the sense of doing CQB all the way out to 500yds reliably with such a tiny 7.5" barrel.

And that bulk Wolf ammo makes it all the better.

The Sig MCX Rattler has a 5.5" barrel for the 300BO and seems to be doing ok.

Hey!  I know that guy.  



It's in a little different config now though.  Still runs like a raped ape, and 600 yards on 10" plates is easy even with Wolf steel case.

I just ordered some new Lehigh Defense 110gr Controlled Chaos bullets from Midway USA.

They expand down to 1500fps.

BC: .405 G1

This will be a great hunting bullet for any barrel length really.

I'll load them over CFE223 in a pressure ladder and see where they end up.

Could be my go-to hunting load for the 12" Grendel.

The numbers are really good for expansion and retained energy.