Stretching 6.5 Grendel

[DavidA]

Starting roughly 10 years ago when the Grendel was a pretty hot article. Then Nosler came out with the 6.5mm 130 RDF in late 2017. With the 123 Scenar, an AR15 in 6.5 Grendel was transonic out to right at 1,000 yds at sea level, assuming you could get 2620 fps out of a 24" barrel. Some could ge close to the speed with 24's , but they just would not shoot. On the Grendel forum , people would just losing their collective minds trying to get it to shoot.

The 130 RDF if it you could make it work, was a game changer. A 123 Scenar has a G7 bc of .263, a 130 RDF .307. It was a beautiful thing,
Except for a shooter here or there, people just could not get it to shoot. It would send out 2" groups ot all day. So then they came out with 6 ARC, which was basically David Tubs 6mm AR. Everyone was ripe for the shift. The 6mm AR was simple to make as well, just using a type s sizing die with a .269 bushing. Most importantly, the 6 mm ARC made the rifle a real 1,000 yd platform. In a 6 ARC shooting ELD M 108 bullets a 24" barrel could get you 2,750 fps.. That would get you transonic to 1,100 yds wit 351 ft lbs. Hornady saw the benefits of the 6mmmAR, and they pushed the shoulder back several thousandths and then said " Look, a new cartridge a 6mm ARC". Any hoot, then the call came for everyone to bow to the 6mm ARC gGod.

However I was not buying it. A 130 RDF, with the right barrel and load could reach 2,600 f0s and maybe a little more from a 24"" barrel. Pretty hot load, trashing your brass, but attainable.

When you compared the 6mm ARC to a hypothetical 130 gr RDF Grendel, it just did not make much sense. the Grendel holds its owne (?actually better than ARC at 1,000 yds 1.93 mils vs 2.18 mills for the ARC. The Grendel is just not as fast⁰ a round, so you have more drop at any given distance, but that is a constant factor. Gravity does not change. Wind to target does. A 130 RDF at 2650 fps will be transonic at sea level to 1,175 yds. At 1,000 yds, sea level, a 130 gr RDF round retains 558 ft lbs , the 6mm ARC 108 ELD M retains only 421 ft lbs. Drop and drift at 1,000 yds Grendel 8.9 mills drop, 1.93 mils drift (10 mph crosswind) The 6mm ARC 9.03 mils drop 2.52 mills drift. If you go to a 6mm 115 RDF adjusting the speed f9r bullet weight the ARC produces 8.72 mills drop and 2.16 mills drift.

So the trick for the Grendel is getting the 130 RDF to shoot. So best velocities are from the Black Hole Weaponry P3 barrels. So last year bought a 24" 264 LBC BHW barrel. Never got it to range, so I started looking at the problems, and it appeared to me the problem is the magazine restriction is 2.3 to 2.29 in ACS mags and less in others. The closer I can get to the lands, I would think would give better results. 130 RDF In the 264 LBC a 130 RDF hits lands at 2.375.

So to get as close as possible, the answers a windowed mag. PRI make a modified windowed 10 rnd 6.8 magazine. I just recently got this mag and decided to see just how close I could get. To feed properly, I had to file the on Notch in the magwell a couple of kits ands wider. Also, the barrel extension just I trades into the magwell so I filled the extension flush with mag well. So now the rifle cycle rounds without getting hung on the extension lip in magwell. The max COAL now is 2.373. So I am thinking of running some loads 2.37 at .005 of lands.. If anything is going to , this will. At 2.370 I should maximize room in boiler room and dam near be kissing the lands.

If this fails, there is the130mgr Berger Hybrid OTM tactical .287 G7 bc. At the same speeds at sea level, 9.92 mils drop , 2.21 mills drift. So while it does not beat the 115 gr RDF ARC , it's close. There is also the 140 gr RDF option. At 2,486 fps the 140 RDF produces 9.87 mils drop 1.93 drift and its transonic to 1,125 yds. A lot more energy as well, with 565 ft lbs at 1,000. Either way, I plan on getting some loads out soon and establishing some base line data.

Any of these will produce more recoil, but my 24" with scope is in the 13 lb range. So I won't notice it.


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[AlBeight]

TL/DR

Paging Mr. SquareGrouper to the white courtesy phone.... He’s your Grendel guy.

 

[Growler215]

I have a similar .264 lbc barrel, except mine is only 22". Just started working up loads for it; so far I have only worked with 123 gr SSTs. For these, my distance to the lands was only 2.275". Best accuracy so far was with bullets seated to 2.245" - a .030" jump.

Just received a new order of bullets for this rifle: 123 gr ELD Match, 120 gr MatchKing HPBT, 120 gr Match Burner, 108 gr Scenar, and 100 gr TTSX. So I'll have more load workup projects this winter.

I got some of the lighter bullets to get better short/medium range velocity, albeit at the cost of a lower BC. I also wanted to start working with some non-lead bullets.

Based on what I've seen so far, I don't think I could get the 123's to 2600 fps, even with the lower friction of polygonal rifling, staying within published maximums.

If I want to seat anything beyond mag length (about 2.310" for my Duramags), I'll probably just single load with a sled. I use my Grendel mags for my 9x39 AR pistol, too, because my actual 9x39 mags are too long for benchrest use.

 

[DavidA]

Yep, I have had very had similar experience with the 123 SST's, I also have a 20" 264 LBC. BHW barrel which it love the 123's. But the scenars out of my 20" at a muzzle velocity of 2,570 sfps go transonic at 975. yds. So the entire purpose of the 24" barrel and getting the 130 RDF's to shoot is to push transonic out to almost 1,200 yds at sea level and keep drift below 2 mils at 1,000. It will make it an interesting set up. I tried getting accuracy out of the 20" with 130's but no joy.

I'm hoping that getting these boys right at lands it will tighten things up. If this works with the 24" I can swap out the 20", and it will be transonic to 1,100 yds. Just have to rework the barrel extensionso it allows the rounds to cycle. I'll let you know how it goes. The only downside is that you would be limited to 10 round modified magazines. You could try modifying a 20 round, but I think it would make the magazine very flimsy. Maybe yo could window a 30 round and make it 15 or 20. That's another problem. Just got to make it shoot the 130 RDF's sub moa..

It will be a while though, I ride motorcycles and I will be trying to get in all the riding I can here in the fall.

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[Squaregrouper]

My 20" PSA barrel prefers the 123gr ELD-M over the 123gr SST by a long shot. It does not like the SST's. It also really likes the 123gr Scenars and 100gr Midsouth Match Monsters (Nosler). The 100gr are really fun at long distance provided the wind is calm.
Somewhere on MDS there is a video of me shooting the 100gr MM at 965yds. I'm pretty sure they were travelling ~2750fps with 8208XBR.

 

[Growler215]

My 20" PSA barrel prefers the 123gr ELD-M over the 123gr SST by a long shot. It does not like the SST's. It also really likes the 123gr Scenars and 100gr Midsouth Match Monsters (Nosler). The 100gr are really fun at long distance provided the wind is calm.
Somewhere on MDS there is a video of me shooting the 100gr MM at 965yds. I'm pretty sure they were travelling ~2750fps with 8208XBR.

What seating depth do you use for the 123 gr ELD-M bullets.? And, if you measured it, how much jump/jam were you at?

Thinking of loading some of these up to take to the range this week. I just measured my distance to the lands with this pill at 2.293".

My best load with the SST's was about 1 moa. Acceptable hunting accuracy I guess, but not what I want from this rifle.

 

[Squaregrouper]

What seating depth do you use for the 123 gr ELD-M bullets.? And, if you measured it, how much jump/jam were you at?

Thinking of loading some of these up to take to the range this week. I just measured my distance to the lands with this pill at 2.293".

My best load with the SST's was about 1 moa. Acceptable hunting accuracy I guess, but not what I want from this rifle.

2.280"

 

[Growler215]

2.280"

Thanks!

 

[DavidA]

Also thinking of trying some 107’s.


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[lazarus]

I have a similar .264 lbc barrel, except mine is only 22". Just started working up loads for it; so far I have only worked with 123 gr SSTs. For these, my distance to the lands was only 2.275". Best accuracy so far was with bullets seated to 2.245" - a .030" jump.

Just received a new order of bullets for this rifle: 123 gr ELD Match, 120 gr MatchKing HPBT, 120 gr Match Burner, 108 gr Scenar, and 100 gr TTSX. So I'll have more load workup projects this winter.

I got some of the lighter bullets to get better short/medium range velocity, albeit at the cost of a lower BC. I also wanted to start working with some non-lead bullets.

Based on what I've seen so far, I don't think I could get the 123's to 2600 fps, even with the lower friction of polygonal rifling, staying within published maximums.

If I want to seat anything beyond mag length (about 2.310" for my Duramags), I'll probably just single load with a sled. I use my Grendel mags for my 9x39 AR pistol, too, because my actual 9x39 mags are too long for benchrest use.

I am going to work up an SST load soon. I have Hornady 123 BTHP match, 120gr fusion, 120gr Nosler ET, and Sierra 120s worked up for my 18" AR and my 20" Howa. The Howa is a big disappointment in velocity*. My 18" AR actually produces about 10-20fps more velocity. Though I've noticed the difference has shrunk. Not sure if that is wear on the Howa, or what. The 18" AR does seem to have very high velocity for the barrel length. Close to max posted CFE223 (.3gr below max) loads I am developing about 2500fps on the 18" AR and only about 2480 on the Howa. I think some is the difference in rifling between the guns. The Howa when brand new was only pushing 2450fps and I've seen the velocity grow about 30fps over around 100 rounds (I haven't put that many through it yet). This is accounting for conditions mind you, so it is an actual increase in velocity and large enough and enough groups over the chrono to be statistically significant.

Those 120 ETs I like, but man they are so long! At least according to GRT, I am at about max pressure for Grendel running them at 1.315 (max mag length in my Howa) and developing about 2250fps. More than enough for good expansion and it isn't like I hunt at extended ranges. I really dislike pushing anything to max pressure, as I'd rather trade 25-50fps for 2-3 more firings of my brass. I do know in my Howa I have the room for most of my loads to push it maybe 100fps, between loading it long, and loading it to max or a little past. The juice doesn't seem to be worth the squeeze to me unless I was hunting at extended ranges or really did need to push it out to 1000yds. I'd probably be better off running my 24" AR upper though. That seems to push a solid 100-125fps more velocity than my 20" Howa.

I have a chubby for Grendel. I just wish that the ammo was cheaper and that 100-123gr projectiles were more common and cheaper. But, eh. It is what it is.

Maybe some day I'll get into 6arc. But my time and money is limited. Finalizing a divorce from a wife who doesn't like guns. So at some point soon here, that won't be an issue that I have to be real careful about what I buy, because she hates them. But time and money will still be limited. I don't want to own a bunch of stuff I never shoot. And for me, I am shooting almost exclusively at 200yds and in, with the rare excursion past that going to some longer range. Hunting I've never taken a shoot or had an opportunity to shoot something past 100yds. Someday, probably. When it comes to that, 6.5 grendel is far superior to 6arc for hunting at any distance. So I'd rather buy a nice 24-26" bolt action rifle in 6.5 grendel to go with my ARs and 20" Howa for long distance, intermediate cartridge shooting than dicker with 6arc.

*Not in any other way though. The Hornady 123 BTHP just aren't super accurate. I am playing footsie with 1MOA with the load I have worked up, but the 120 Nosler ETs if I hand sort the bullets (because what I got was from American Reloading, and they have 3 different crimp groove styles on the bullets) I am getting .6MOA 5 shot groups. The Sierra 120gr matchkings I am also playing "just the tip" with around .6MOA 5 shot groups. ~2450fps for 120/123s kills deer plenty dead. The actions is very slick, trigger is great, balance is wonderful. Even with my Omega 300 on the end, the weight isn't bad at all with the heavy barrel (just under 8.5lbs with suppressor on, loaded magazine, 3-9x40 Whiskey 3 scope, rings, and sling. About the same weight as my 308 Sako Forester, not wearing a can). and the balance is pretty good, just forward of the magazine so it is easy to carry. Not as compact as I'd really like. A 16.1" barrel would be much better for that, but with the shorter action size and shorter barrel, it is only slightly longer than my Sako Forester with it's ~23" barrel and longer action. Also I wouldn't really want to trade the ~100-125fps velocity I'd probably lose with 4" shorter barrel. If I want a really short suppressed rifle setup, I'd go with a 16.1" Howa in 300 BO. Speaking of, out of the divorce, that is high on my list of barreled actions/rifles to get.

 

[DavidA]

Just for everybody’s information I have a 20 inch black hole weaponry 264 LBC barrel and I shot that for a while. Then I decided that I wanted to get an extra hundred feet a second or so, and make a long range rifle. I then got a 24 inch black hole weaponry 264 LBC barrel. I’ve measured all of my bullets that I use for 6.5 Grendel from a 107 SMK’s to a 140 Nosler RDF. So same manufacturer, same cartridge, same chamber reamer. But to a point for every bullets the distance to the land is .030” less in the 20 inch barrel.
Go figure.


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[outrider58]

2.280"

Are you using 'Grendel' mags?

 

[Squaregrouper]

Are you using 'Grendel' mags?

E-Lander 6.5 Grendel magazines.
I would double check my load data when I get home

 

[Bountied]

My 20" PSA barrel prefers the 123gr ELD-M over the 123gr SST by a long shot. It does not like the SST's. It also really likes the 123gr Scenars and 100gr Midsouth Match Monsters (Nosler). The 100gr are really fun at long distance provided the wind is calm.
Somewhere on MDS there is a video of me shooting the 100gr MM at 965yds. I'm pretty sure they were travelling ~2750fps with 8208XBR.

I like the ELD-Ms as well. But not is 6.5G. I can't remember who but they were saying that the Hornady bullets tend to fragment in flight. I haven't seen that but I'm not sure what his velocity/twist rate was. I think with a fast twist and high velocity you could get any bullet to disintegrate mid flight.

 

[4g64loser]

I like the ELD-Ms as well. But not is 6.5G. I can't remember who but they were saying that the Hornady bullets tend to fragment in flight. I haven't seen that but I'm not sure what his velocity/twist rate was. I think with a fast twist and high velocity you could get any bullet to disintegrate mid flight.

I'm one of many who has had hornady garbage issues. My issues with them are many but the one you are probably referring to is when I was blowing up 75hpbt. 9 twist bbl, 22-250ai. I went to Nosler and the problems went away. Sierras worked too but the nosler 53 and 55 and 69 pills all hammered and 55 blitzkings were unobtainable.

I'll say that if you cruise precision rifle shooting oriented forums you will see plenty of people airing dirty laundry. I've seen the factory loaded 6.5 creed stuff puff in midair. I was on glass. I've definitely seen it happen with guys reaching for top speed handloading. Most are running 8 twist tubes, the creedmoor standard. There's probably some guys with 7.5 twists that have popped em as well. I recently let a student shoot some hornady match ammo in on of my rifles. The barrel doesn't have 700 rounds on it yet and never coppers up. One box of hornady fugged that all up. Never again. Their jackets are garbage.

To be absolutely transparent, bullet blow up is NOT exclusively a hornady issue. The old berger bullets tended to pop in 6.5-284 F open guns, especially in Krieger tubes. Guys used Sierras and had no issues. Berger now offers the "target" and."hunting" versions of their VLDs. Jackets are the major difference based on sectioning some. If you kept the VLD 140s at 260 speeds, no issues. The extra horsepower of the 284 case, coupled with the sharp krieger lands, was a bit too much. My 6 Bitchslap (6-284 Improved) barrels wouldn't run VLDH 105s. They exploded. The 105 hybrid target, just fine. Thicker jacket. Ditto nosler and Sierra 107s. Hornady is unique (in my experience) in having these issues in factory ammo and when loading their projectiles in cases they are expressly intended for. Hornady "tech" told me there was no upper limit for their 75s. This is inherently false as there is ALWAYS an upper limit for velocity it is simply that most people are never going to hit it as it would require a case that is overcome to the "practical joke" level for a well constructed bullet. In the spirit of fairness, I once tried to "pop" nosler Btip varmint pills in 22-250ai barrels. One 14 twist pipe would run the 40s up to over 4400. They loved it. I tried 55s in a 9 twist to see if upping the RPM would do what sheer velocity wouldn't. Nope. They worked fine and actually seemed a bit more violent on impact. Sample size was small so I can't call that a real conclusion.

 

[Squaregrouper]

Thanks!

Are you using 'Grendel' mags?

E-Lander 6.5 Grendel magazines.
I would double check my load data when I get home

My calipers confirmed the length.
I only put that label on a box once it is a developed load. When I'm working up a load the info will be on a business card inside the box.
.

 

[Squaregrouper]

I'm one of many who has had hornady garbage issues. My issues with them are many but the one you are probably referring to is when I was blowing up 75hpbt. 9 twist bbl, 22-250ai. I went to Nosler and the problems went away. Sierras worked too but the nosler 53 and 55 and 69 pills all hammered and 55 blitzkings were unobtainable.

I'll say that if you cruise precision rifle shooting oriented forums you will see plenty of people airing dirty laundry. I've seen the factory loaded 6.5 creed stuff puff in midair. I was on glass. I've definitely seen it happen with guys reaching for top speed handloading. Most are running 8 twist tubes, the creedmoor standard. There's probably some guys with 7.5 twists that have popped em as well. I recently let a student shoot some hornady match ammo in on of my rifles. The barrel doesn't have 700 rounds on it yet and never coppers up. One box of hornady fugged that all up. Never again. Their jackets are garbage.

To be absolutely transparent, bullet blow up is NOT exclusively a hornady issue. The old berger bullets tended to pop in 6.5-284 F open guns, especially in Krieger tubes. Guys used Sierras and had no issues. Berger now offers the "target" and."hunting" versions of their VLDs. Jackets are the major difference based on sectioning some. If you kept the VLD 140s at 260 speeds, no issues. The extra horsepower of the 284 case, coupled with the sharp krieger lands, was a bit too much. My 6 Bitchslap (6-284 Improved) barrels wouldn't run VLDH 105s. They exploded. The 105 hybrid target, just fine. Thicker jacket. Ditto nosler and Sierra 107s. Hornady is unique (in my experience) in having these issues in factory ammo and when loading their projectiles in cases they are expressly intended for. Hornady "tech" told me there was no upper limit for their 75s. This is inherently false as there is ALWAYS an upper limit for velocity it is simply that most people are never going to hit it as it would require a case that is overcome to the "practical joke" level for a well constructed bullet. In the spirit of fairness, I once tried to "pop" nosler Btip varmint pills in 22-250ai barrels. One 14 twist pipe would run the 40s up to over 4400. They loved it. I tried 55s in a 9 twist to see if upping the RPM would do what sheer velocity wouldn't. Nope. They worked fine and actually seemed a bit more violent on impact. Sample size was small so I can't call that a real conclusion.

You're the reason I'm transitioning to 123gr Scenars for my Grendel.
I haven't had any issues with the 123gr ELD-M, but you have a LOT more long-distance range time than I.

 

[outrider58]

My calipers confirmed the length.
I only put that label on a box once it is a developed load. When I'm working up a load the info will be on a business card inside the box.
.

Thanks Ky.

 

[4g64loser]

You're the reason I'm transitioning to 123gr Scenars for my Grendel.
I haven't had any issues with the 123gr ELD-M, but you have a LOT more long-distance range time than I.

At Grendel velocities, you really shouldn't. The only thing I'd expect to see happen that's unsavoury is the copper fouling issue. My buddy dumped the 95vmax and went to the 90varmageddon and 100cc nosler bullets in his (shorter throat slower twist) Grendel gasgun.

That said, you will never regret going to better bullets. I sure never have. I'm mostly berger and nosler these days but I still run 2156 sierras in my 308. Love that bullet and have a LOT of them downrange so I'm very comfortable with it on the loading bench and on the line. The scenars (especially the 155 in 30cals) are something of a cult further west. There are apparently guys who use them for elk and swear by them. My friend/coworker at the other job uses them in his 300wm on deer and has hammered plenty of elk with them too.

Biggest thing I have found by going to better bullets and case prep is that unexplained flyers have mostly gone away. In my bolt guns, I'm fanatical about my neck tension consistency. Turned necks, annealed every firing, sized in bushings only with no expander. This was the biggest "gain" in bringing velocity consistency to eliminate "highs and lows ". In a gasgun, probably not feasible without some modifications to protect the brass from neck damage. I did add some old wetsuit material to the side of my friends upper receiver to minimize neck damage during ejection. He's also gone to a TBR brass catcher.

 

[Growler215]

Just for everybody’s information I have a 20 inch black hole weaponry 264 LBC barrel and I shot that for a while. Then I decided that I wanted to get an extra hundred feet a second or so, and make a long range rifle. I then got a 24 inch black hole weaponry 264 LBC barrel. I’ve measured all of my bullets that I use for 6.5 Grendel from a 107 SMK’s to a 140 Nosler RDF. So same manufacturer, same cartridge, same chamber reamer. But to a point for every bullets the distance to the land is .030” less in the 20 inch barrel.
Go figure.


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That could make it pretty challenging to develop loads that work well in both rifles, although Berger apparently thinks there is a .030-.040" wide seating depth accuracy node for secant ogive bullets.

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