New 6mm Advanced Rifle Cartridge

[Dino11]

Factory ammo that I measured was 1.1825 measured at the datum line, that was an example of 10 cases that I measured... unfired.

Ammo fired from my bolt gun measured 1.186... ammo fired from one of my DI guns measured 1.190.

SAAMI spec to the datum line is 1.190 -.007... so 1.183 to 1.190 is spec for this cartridge.

The Hornady rounds were just under minimum spec by .0005, but that is splitting hairs on the measuring. I was actually surprised at the consistency of the factory rounds.

I think what you are seeing is normal case expansion of the case above the web, I to see this on my cases and that is out of four different rifles. It almost disappears after full length resizing. And some of my cases have been loaded 8 or 9 times, I have not yet lost a case to it having loose primer pocket or any signs of weakening from firing. I think it is just a characteristic of this round along with light ejector swipes on the DI guns.

I have shot and reloaded a lot of 6mm ARC, and always have loaded under max load per Hornady and Hodgen spec.

 

[crystalgold7mm]

Well I think I know whats causing the ring in my gun. I just put a faxon match barrel with a JP enterprises grendel bolt on my gun and when I measured the headspace, it came out to .006-7" Which is equivalent to a field guage headspace. The case is stretching too much and I suspect pushing the bolt slightly to the rear starting to unlock causes the case to bulge at the back of the chamber. I will have to have a bolt custom made if If I want to tighten up the headspace.

 

[Yondering]

Well I think I know whats causing the ring in my gun. I just put a faxon match barrel with a JP enterprises grendel bolt on my gun and when I measured the headspace, it came out to .006-7" Which is equivalent to a field guage headspace. The case is stretching too much and I suspect pushing the bolt slightly to the rear starting to unlock causes the case to bulge at the back of the chamber. I will have to have a bolt custom made if If I want to tighten up the headspace.

No, that’s not enough headspace to cause a ring. A case head separation ring (which is what headspace causes) is a different thing than the belt being discussed here anyway; two completely unrelated things.

Also, “pushing the bolt to the rear” does not start the unlocking process; that’s not how an AR works. The carrier has to be pushed rearward by gas pressure inside it, and that unlocks the bolt by causing it to rotate. None of that has anything to do with headspace.

That amount of headspace might pose a problem eventually after 4-6 firings of the same piece of brass, but not with one firing of factory ammo. If you measured a bunch of factory ammo for various rounds you’d find the base to datum length often leaves a lot more headspace than that anyway.

 

[SBRSarge]

My Odin barrel continues to tighten. Groups in the first 25 rounds averaged a bit over an moa. Rounds 50-75 averaged .86 moa.

For those you with more experience, is there an average number of rounds, or range of rounds, where groups stabilize? Or are there just too many variables?

This is the first barrel I’ve paid any attention to as far as round counts and group size. I know other barrels like my Wilsons and Noveske have tightened up with use, but I never kept count.

 

[godofthunder]

Had to send my barrel in to BA due to accuracy issues and damaging my brass. I didn't get an explanation in to what they found, but they sent a new barrel out and it should be in today. With any luck I'll go sight it in this weekend.

 

[raptor99]

Factory ammo that I measured was 1.1825 measured at the datum line, that was an example of 10 cases that I measured... unfired.

Ammo fired from my bolt gun measured 1.186... ammo fired from one of my DI guns measured 1.190.

SAAMI spec to the datum line is 1.190 -.007... so 1.183 to 1.190 is spec for this cartridge.

The Hornady rounds were just under minimum spec by .0005, but that is splitting hairs on the measuring. I was actually surprised at the consistency of the factory rounds.

I think what you are seeing is normal case expansion of the case above the web, I to see this on my cases and that is out of four different rifles. It almost disappears after full length resizing. And some of my cases have been loaded 8 or 9 times, I have not yet lost a case to it having loose primer pocket or any signs of weakening from firing. I think it is just a characteristic of this round along with light ejector swipes on the DI guns.

I have shot and reloaded a lot of 6mm ARC, and always have loaded under max load per Hornady and Hodgen spec.

Dino11 what are you loading for powder and bullet?? And what is your load that your using??? Thanks!!!

 

[raptor99]

My Odin barrel continues to tighten. Groups in the first 25 rounds averaged a bit over an moa. Rounds 50-75 averaged .86 moa.

For those you with more experience, is there an average number of rounds, or range of rounds, where groups stabilize? Or are there just too many variables?

This is the first barrel I’ve paid any attention to as far as round counts and group size. I know other barrels like my Wilsons and Noveske have tightened up with use, but I never kept count.

My barrel shot .5 groups in the first 50rds of load testing. I have seen new barrels shoot really tight groups. The only thing that may change is that your barrel usually picks up velocity after a hundred rounds or so.....

 

[CIB2007]

Is anyone running a piston set up? I have a 18in barrel from craddock being spun up now and he doing a rifle length gas system with an oversized gas port.

 

[Dino11]

Dino11 what are you loading for powder and bullet?? And what is your load that your using??? Thanks!!!

For my gas gun I am using Lever for the powder and most of the bullets I load are Nosler RDF 105 gr.

For folks loading the Nosler RDF's, keep in mind that I have found these bullets like to jump to the lead. My jump is between 55-60 thousands. I am still working on the load for my bolt action rifle. I loaded some on the long side and only jumped them about .020 and it did not like them. Loaded some more today and jumped them .060 and I would bet that they will be more accurate. I know a lot of folks like to jam everything up againt the lands or just off them, that does not always work in my findings..

Here is an excellent read on the subject I found, and it has some interesting links in it to.

https://precisionrifleblog.com/2020/03/21/bullet-jump-and-seating-depth-reloading-best-practices/

https://precisionrifleblog.com/2020/03/29/bullet-jump-load-development/

 

[fifdynutz]

Has anyone worked up a load with the 90g ELD-X and CFE-223?

im running a 14.5" faxon barreled pistol for night hunting and id like to flatten out my trajectory a bit, its difficult to judge distance at night. ive been running box 105g hornady black all winter and im starting to run low, I need a solid starting load for the 90's because full load development sucks while im in the middle of a season (removing thermal, installing day scope, sight in, etc) it would be nice to only test a .6g range or so. Thanks!

 

[Yondering]

Has anyone worked up a load with the 90g ELD-X and CFE-223?

im running a 14.5" faxon barreled pistol for night hunting and id like to flatten out my trajectory a bit, its difficult to judge distance at night. ive been running box 105g hornady black all winter and im starting to run low, I need a solid starting load for the 90's because full load development sucks while im in the middle of a season (removing thermal, installing day scope, sight in, etc) it would be nice to only test a .6g range or so. Thanks!

I did with Lever but not with CFE223. Performance of the two is fairly close though, and I'd say you're on the right track for flattening out trajectory for hunting. If it were my rifle, I'd probably start around 29.0gr and work up to around 2750-2800 fps. I say that based on what my 12.5" barrel will do; YMMV but that should be in the ballpark.

FWIW the 90gr TGK is capable of about 100 fps faster than the ELDx, due to the nose profile affecting jump and powder capacity. Another forum member who got me looking at both of these explained that he had poor results on coyotes with both bullets, but that 90 TGK sure makes a flat shooting target round anyway. I have not put either one into live meat yet, personally.

Another option, if you aren't shooting much past a couple hundred yards (you said night hunting so guessing the ranges aren't real long?) the Speer 100gr SP is one of the cheapest 6mm bullets available and performs really well in the velocity range you'd be using them. It's not sleek, sexy, or new, but for reasonably close range hunting at 2300-2800 fps a good cup and core soft point can work really well.

 

[Yondering]

For my gas gun I am using Lever for the powder and most of the bullets I load are Nosler RDF 105 gr.

For folks loading the Nosler RDF's, keep in mind that I have found these bullets like to jump to the lead. My jump is between 55-60 thousands. I am still working on the load for my bolt action rifle. I loaded some on the long side and only jumped them about .020 and it did not like them. Loaded some more today and jumped them .060 and I would bet that they will be more accurate. I know a lot of folks like to jam everything up againt the lands or just off them, that does not always work in my findings..

Here is an excellent read on the subject I found, and it has some interesting links in it to.

https://precisionrifleblog.com/2020/03/21/bullet-jump-and-seating-depth-reloading-best-practices/

https://precisionrifleblog.com/2020/03/29/bullet-jump-load-development/

I'm not sure how much precision loading you've done for other AR cartridges so maybe you already know this, but just FYI, .055-.060 jump is way shorter than most AR setups are restricted to with other cartridges. That's one of the special and relatively unique things about the 6 ARC (and older 6 Grendel variants); the short fat case allows getting long match bullets close to the lands or even touching while still fitting the magazine, while other cartridges are mostly resigned to a long jump to the lands.

For a more common example of what I'm talking about, consider the 70gr RDF in a 5.56 chamber. At normal magazine length, you'll usually have somewhere between .150"-.250" jump to the lands, and in my experience the RDF does not shoot well that way (although some other bullets do). I've experimented with cut magazines for my 5.56; using ASC cut mags allows me to load out to 2.355" OAL, and the 70 RDF starts to shoot well at about that length in the rifle I've done the experimenting with, but it's still jumping over .100" and would do better closer. The only way to get there in a 5.56 though is to remove some material at the front of the mag well and feed ramp.

My only point here really is just to illustrate how neat it is with this 6 ARC that we can seat bullets right up to the lands or at least close to it.
Word to the wise though - don't jam bullets into the lands in an AR unless it's a bench-only rifle and you can guarantee never having to extract a live round. Dumping powder into the action sucks. I've had to do it sometimes for fireforming wildcats, but it's something to be careful about and not a good general practice.

 

[Dino11]

Every barrel is different... The ARC chamber is cut differently than a standard 5.56 chamber. The ARC is much tighter in the bullet to lands. This is why Hornady had problems with the early release 105's. I have had good luck jumping the RDF's, much better accuracy than when loaded close to the lands. You can actually load the RDF 105's to 2.270 and still not hit the lands, they are very sleek and slender. I loaded the last batch of them to this spec, it was as long as I could go and fit the magazine. They didn't group very well. Generally I load them to jump .060, but may try to jump them to .080 or more in the bolt gun. I have just started load development on it.

And I agree with you about the 100 gr. Speers, they will make a good hunting round. And they will hit pretty hard out at distance, they are pretty accurate pills and get pretty good velocity numbers. I was shooting 600 yard steel the other day with some, and they grouped sub MOA at 100 yards .I think some of the tips get damaged loading into the chamber. Not match grade accuracy, I was getting a couple of flyers but they are my fouling and plinking rounds. I might use them to fire form some Grendel brass I just acquired. American Reloading has them back in stock, not pulled units but new ones for 80 bucks.

 

[raptor99]

Has anyone worked up a load with the 90g ELD-X and CFE-223?

im running a 14.5" faxon barreled pistol for night hunting and id like to flatten out my trajectory a bit, its difficult to judge distance at night. ive been running box 105g hornady black all winter and im starting to run low, I need a solid starting load for the 90's because full load development sucks while im in the middle of a season (removing thermal, installing day scope, sight in, etc) it would be nice to only test a .6g range or so. Thanks!

30grs of LVR with a 90ELDX shot under an inch for me. Also the 85 Sierra HP and the 87VMAXs are a really great bullet in my gun. I was getting .5 five shot groups with the 87VMAX and Varget but my loads were to hot. SOoo I am looking at CFE and LVR now......

 

[godofthunder]

FWIW the 90gr TGK is capable of about 100 fps faster than the ELDx, due to the nose profile affecting jump and powder capacity. Another forum member who got me looking at both of these explained that he had poor results on coyotes with both bullets, but that 90 TGK sure makes a flat shooting target round anyway. I have not put either one into live meat yet, personally.

That's disappointing to hear. I want to load in the 90gr range and was primarily interested in the TGK due to price and extra speed.

 

[SupressYourself]

If you can get your hands on any, I'd look into the 87 v-max. I run it at 2950fps out of my 243 LBC (basically a wildcat equivalent of the 6 ARC) and it flattens coyotes.

 

[fifdynutz]

I also have some 80g SBK's I can try, just can't find shit for quality data on those or the 90s with cfe...I also have varget and 4985 that might work but looks slow to the charts

 

[raptor99]

I also have some 80g SBK's I can try, just can't find shit for quality data on those or the 90s with cfe...I also have varget and 4985 that might work but looks slow to the charts

Varget really shot well for me in my gun but I got a lot of pressure with it. Hornady showed like 29.7grs and I kept getting the "Grendel Belt" on my brass. Then Hogdgen came out with their data and in theirs it was maxed at 28grs!!!

 

[Yondering]

Varget really shot well for me in my gun but I got a lot of pressure with it. Hornady showed like 29.7grs and I kept getting the "Grendel Belt" on my brass. Then Hogdgen came out with their data and in theirs it was maxed at 28grs!!!

Varget spikes pretty hard when you approach max pressure. That's another reason I like Lever so much; it's more stable and predictable when working up at max pressure.

 

[fifdynutz]

I think im going to try these loads to start, if they group well and have an acceptable SD for night hunting i just might roll with it for the rest of the season

80g SBK- IMR4895 27.8g

90g ELDX- CFE223 30.4g

103g ELDX- CFE223 28.6g
VARGET 26.6g

 

[LRBuck]

Varget really shot well for me in my gun but I got a lot of pressure with it. Hornady showed like 29.7grs and I kept getting the "Grendel Belt" on my brass. Then Hogdgen came out with their data and in theirs it was maxed at 28grs!!!

I am confused. I am still pretty new at reloading and the data from Hornady and Hodgdon that I am looking at is quite different for the heavier bullets (107-110grains)
Hornady (for gas guns) = max varget charge of 26.7grains
Hodgdon = max varget charge of 25.8C

For Leverevolution it is:
Hornady = max is 29.7
Hodgdon = max 28.2

Raptor99,
1) are you loading at 29.7 of Varget for a bolt rifle?
2) Are you shooting lighter bullets to get 29.7 grains of Varget as a max (87vmax)?

Anyone,
3) why are the Hornady and Hodgdon max loads so different and what should we do to reconcile these different max charge weights?
4) anyone else developed a load with Berger 109g LRHTs?

I developed a load for 109g Berger LRHT over 29.6 grains of Lever before I ever saw the Hodgdon data. But this load has produced very good groups overall (best = .36 inch) and good speeds (avg. aprox 2740).

Still fine tuning it as I have had some function issues (with the load but not any with factory ammo) in my +2 rifle gas system, 22” barrel. I hope I have solved this with a combination of a lighter buffer spring, lighter buffer weight and slight modification of a Grendel magazine). I will report back more on this experience/process later on.

I worked this load up believing that it was under the max charge (Hornady = 29.7) but now I see Hodgdon’s max. To my very green reloading brain >1 grain max charge difference seems like a pretty big one. I don’t want to push the limits with this and I don’t want to break my bolt. For my goals, (shooting out to 1200) I don’t need anymore velocity and could give up some. I am not seeing any pressure signs but understand that is not the tell with 52kpsi limits in the 6 arc gas rifle.
I look forward to reading the responses. Thanks!

 

[Yondering]

I am confused. I am still pretty new at reloading and the data from Hornady and Hodgdon that I am looking at is quite different for the heavier bullets (107-110grains)
Hornady (for gas guns) = max varget charge of 26.7grains
Hodgdon = max varget charge of 25.8C

For Leverevolution it is:
Hornady = max is 29.7
Hodgdon = max 28.2

Raptor99,
1) are you loading at 29.7 of Varget for a bolt rifle?
2) Are you shooting lighter bullets to get 29.7 grains of Varget as a max (87vmax)?

Anyone,
3) why are the Hornady and Hodgdon max loads so different and what should we do to reconcile these different max charge weights?
4) anyone else developed a load with Berger 109g LRHTs?

I developed a load for 109g Berger LRHT over 29.6 grains of Lever before I ever saw the Hodgdon data. But this load has produced very good groups overall (best = .36 inch) and good speeds (avg. aprox 2740).

Still fine tuning it as I have had some function issues (with the load but not any with factory ammo) in my +2 rifle gas system, 22” barrel. I hope I have solved this with a combination of a lighter buffer spring, lighter buffer weight and slight modification of a Grendel magazine). I will report back more on this experience/process later on.

I worked this load up believing that it was under the max charge (Hornady = 29.7) but now I see Hodgdon’s max. To my very green reloading brain >1 grain max charge difference seems like a pretty big one. I don’t want to push the limits with this and I don’t want to break my bolt. For my goals, (shooting out to 1200) I don’t need anymore velocity and could give up some. I am not seeing any pressure signs but understand that is not the tell with 52kpsi limits in the 6 arc gas rifle.
I look forward to reading the responses. Thanks!

That difference in load data is not uncommon (and sometimes a lot larger!) and just illustrates the possible differences between rifle chambers and other variables.

I can say from my own experience that Hodgdon’s data is often a bit conservative in real world rifle barrels, which is probably a result of their choice of test barrels and other factors. That’s not necessarily a bad thing though, especially if you end up with a tight chamber that performs like theirs did.

This is one reason a chronograph is so useful in reloading. When trying out a new rifle, use the more conservative data; if your velocity results match what you’d expect from that data, great. If they are significantly lower though, it indicates your loads aren’t getting up to the same pressures as that data, so then take a look at the other hotter data.

In my experience with the 243 LBC in 3 different rifles, Hornady’s data is pretty spot on with good correlation to my field results.

 

[Gharms]

I got my 21" Odin Works set up and have made a few range trips with it, the first to burn up some factory 108gr for brass, and then a few load development attempts.

Out of my 21" barrel, 108gr factory loads chrono'd at an average of 2,663 fps.

First loads were some 85gr Sierra GKs I had laying around and 105gr Barnes, both over LVR.

View attachment 7590672

View attachment 7590673

Not terrible, except when I loaded up some varying oals for 85gr with 31gr LVR, and 105gr with 29.2 gr LVR and went back, things fell apart for no apparent reason. Only real difference was that the second trip was about 30 deg cooler than the first. I almost always use temp insensitive powders, so my experience with sensitive ball powders is very limited, but I wouldn't think there's any way a 30 deg temp difference could change velocities enough to throw you out of a node? I also wound up having to turn up the gas on the second trip a few clicks. Admittedly I set the GB up so the rifle will run suppressed but not otherwise, still, no failures the first trip, but it started feeling sluggish and failing to strip the next round (only with the 105s, 85s cycled fine) on the second cooler trip. Alternatively, I may have just been shooting poorly the second trip. More work to be done, but ~ 2,950 seems pretty healthy for 85 gr though!

Thanks for posting this. I'm working on a load for a 20" gasser and I'm having similar patterns using 29.5 LVR and Berger 108 VLD Hunts. Velocity is Avg 2592. Can't make the darn thing shoot inside an inch all the time. I'm jumping them around .070 due to performance and magazine. Not impressed yet but we shall continue on. I'm wondering if slowing them way down like to 2400fps would tighten groups up.

 

[LRBuck]

That difference in load data is not uncommon (and sometimes a lot larger!) and just illustrates the possible differences between rifle chambers and other variables.

I can say from my own experience that Hodgdon’s data is often a bit conservative in real world rifle barrels, which is probably a result of their choice of test barrels and other factors. That’s not necessarily a bad thing though, especially if you end up with a tight chamber that performs like theirs did.

This is one reason a chronograph is so useful in reloading. When trying out a new rifle, use the more conservative data; if your velocity results match what you’d expect from that data, great. If they are significantly lower though, it indicates your loads aren’t getting up to the same pressures as that data, so then take a look at the other hotter data.

In my experience with the 243 LBC in 3 different rifles, Hornady’s data is pretty spot on with good correlation to my field results.

Thank you Yondering!

Velocity with my load is a bit faster that what Hornady says is the velocity for their max charge.
My load =29.6 of Lever producing avg 2740 (aprox 65 deg temp)
Hornady max data = 29.7 of Lever producing 2695. (For a 22” barrel)

Should I back off some or do you think I am ok here? Even with the warmer temps of spring/summer?

No pressure signs. Not quite a compressed load but close. I thought I detected a little crunch once when I seated the bullets a little deeper than I am now with a COAL of 2.260, which gets them about .063 off the lands.

 

[SupressYourself]

I think @Henryrifle and some others have mentioned some primer tests, but I just started playing with Lever, and groups and ES with CCI 450 primers were so-so compared to my standard H4895 load.
Then I switched to CCI 400s, and holy crap! Both groups and ES shrunk significantly, and MV increased 10-20 FPS per charge. YMMV...

 

[Dino11]

Thank you Yondering!

Velocity with my load is a bit faster that what Hornady says is the velocity for their max charge.
My load =29.6 of Lever producing avg 2740 (aprox 65 deg temp)
Hornady max data = 29.7 of Lever producing 2695. (For a 22” barrel)

Hornady's data is based off an 18" barrel, which will give your barrel the advantage over theirs if your barrel is longer.

Do you have a 22" Odin barrel? I have one of their 18" barrels and it gives me more velocity over another 18" barrel I have with the same ammo. I also have a 20" barrel and the velocity of the Odin 18" pretty much matches the 20". I think that the tight chamber and the +2 gas length attribute to it being a little faster

 

[MPDS13]

I don't post much, but I'm so tickled with this thing. JP bolt, Proof barrel, Trigger tech. Factory ammo.

Consecutive groups are 3x, 3x and 4x @ 100y. 3 for 3 @ 950y on a 10" steel plate in ~12sec.

View attachment 7572360View attachment 7572362

Great build! Awesome shooting. How are you liking that Ergo 90 grip?

 

[Yondering]

Thank you Yondering!

Velocity with my load is a bit faster that what Hornady says is the velocity for their max charge.
My load =29.6 of Lever producing avg 2740 (aprox 65 deg temp)
Hornady max data = 29.7 of Lever producing 2695. (For a 22” barrel)

Should I back off some or do you think I am ok here? Even with the warmer temps of spring/summer?

No pressure signs. Not quite a compressed load but close. I thought I detected a little crunch once when I seated the bullets a little deeper than I am now with a COAL of 2.260, which gets them about .063 off the lands.

As Dino said, gotta keep in mind barrel length when you're comparing load data velocity numbers. Hornady pulled a switcheroo with their 6 ARC data, using an 18" barrel for their AR data (when most other data is for 24" barrels) and then used a 24" for their bolt gun data.

In theory Hornady's 18" AR data should run about 100 fps faster for max loads with a 22" barrel, although that can vary quite a bit depending on the barrel and components.

 

[MemphisMtnr]

Great build! Awesome shooting. How are you liking that Ergo 90 grip?

I like it, likely to put one on my XLR bolt guns. Feels a little more precision oriented to me than a standard AR grip. But that might just be tricking my muscle memory from plinking with ARs.

 

[Dino11]

I'm not sure how much precision loading you've done for other AR cartridges so maybe you already know this, but just FYI, .055-.060 jump is way shorter than most AR setups are restricted to with other cartridges. That's one of the special and relatively unique things about the 6 ARC (and older 6 Grendel variants); the short fat case allows getting long match bullets close to the lands or even touching while still fitting the magazine, while other cartridges are mostly resigned to a long jump to the lands.

For a more common example of what I'm talking about, consider the 70gr RDF in a 5.56 chamber. At normal magazine length, you'll usually have somewhere between .150"-.250" jump to the lands, and in my experience the RDF does not shoot well that way (although some other bullets do). I've experimented with cut magazines for my 5.56; using ASC cut mags allows me to load out to 2.355" OAL, and the 70 RDF starts to shoot well at about that length in the rifle I've done the experimenting with, but it's still jumping over .100" and would do better closer. The only way to get there in a 5.56 though is to remove some material at the front of the mag well and feed ramp.

My only point here really is just to illustrate how neat it is with this 6 ARC that we can seat bullets right up to the lands or at least close to it.
Word to the wise though - don't jam bullets into the lands in an AR unless it's a bench-only rifle and you can guarantee never having to extract a live round. Dumping powder into the action sucks. I've had to do it sometimes for fireforming wildcats, but it's something to be careful about and not a good general practice.

Another article I found about long jumping bullets, it seems to be what is working now a days with these combination secant/tangent ogive bullets.
I have been having good luck jumping the RDF's @ .060 or more.

https://www.jamerllc.com/jamer-in-action/berger-and-the-long-jump

 

[Yondering]

Another article I found about long jumping bullets, it seems to be what is working now a days with these combination secant/tangent ogive bullets.
I have been having good luck jumping the RDF's @ .060 or more.

https://www.jamerllc.com/jamer-in-action/berger-and-the-long-jump

I'm very familiar with jumping bullets to the lands and wasn't commenting on whether it was the right/best thing to do or not. I think you missed the whole point of that post:

My only point here really is just to illustrate how neat it is with this 6 ARC that we can seat bullets right up to the lands or at least close to it.

With most AR15 setups in other chamberings, we're forced to jump a lot farther, and your .060" jump is not a long jump at all; on the contrary it's pretty short for most ARs that aren't chambered in one of these Grendel-based cartridges. When you say the RDF bullets like to be jumped a lot, try doing that in a 5.56 where you're forced to jump them .200" or more. Perhaps you're used to short action bolt guns and being able to kiss the lands if you want; most of the time you can't do that in an AR. That is all I was pointing out; I don't care how much you're jumping your particular load and you don't need to justify it to me.

 

[Dino11]

I really wasn't trying to justify anything, I thought I was replying to a post about 6mm ARC, not about a .223/5.56. I was only passing on what I found to work for my rifles, both bolt action and DI in 6mm ARC. I have to load two different loads, one for DI and one for bolt action and I have to keep the brass segregated for each. The new bullet shapes that are now out require a different approach as to how they are loaded. And most all the top shooters are finding that jumping the bullet .060 to as far out as .150 is not uncommon now. These are the same shooters that were loading to the lands or just off them, they have come to realize that this is not the best approach with the new bullet types.

 

[LRBuck]

Hornady's data is based off an 18" barrel, which will give your barrel the advantage over theirs if your barrel is longer.

Do you have a 22" Odin barrel? I have one of their 18" barrels and it gives me more velocity over another 18" barrel I have with the same ammo. I also have a 20" barrel and the velocity of the Odin 18" pretty much matches the 20". I think that the tight chamber and the +2 gas length attribute to it being a little faster

I have a 22” Rock Creek from Craddock Precision. What you and Yondering have said makes sense.
The velocity I posted (2695) for 29.7 grains of Lever was from Hornady’s max charge listing for a 22” barrel.

I was able to get in a day of shooting yesterday and this load (29.6g Lever over the 109 Berger’s) was terrific. It was cold (high about 37) and very windy on top of the a ridge in SW Va. Gusty 10-20mph. Shooting steel, after 1 ranging shot, hit the 1200 plate 6x in a row. This bullet was (I thought) very consistent in the wind, and I had repeated follow up hits at 1200 holding 6 MOA for wind. Very consistent at other ranges inside 1200 too. This was my goal (accurate to 1200) in putting this AR together.

I had the magneto on for the first 5 shots and found the speed of 29.6 of Lever had dropped down to an avg of 2690 when it was still about 29 or 30 degrees out. For my rifle, so far I have been avg about 2740 in the 60’s and a bit more in the low 70’s. So it was also a great day to start building a data set for the velocity of Lever with this load due to temperature changes.

 

[Yondering]

I have a 22” Rock Creek from Craddock Precision. What you and Yondering have said makes sense.
The velocity I posted (2695) for 29.7 grains of Lever was from Hornady’s max charge listing for a 22” barrel.

No, that Hornady data is for an 18” barrel, not 22”.
That’s what I was trying to point out to you earlier.

 

[raptor99]

Had a shot out Ruger RPR 6mm Proof SS barrel,. It went south and started throwing rounds past 600 so I pulled it. On a normal rifle I would have set it back and shot it some more since it was not fire cracked just the throat was gone. SO to make a long story short I talked to my smith about cutting both ends off of it and making me an AR 6mmARC barrel!! I just got it back and put together and took it out to try out. Factory was around 1.1 to 1.2 but this did not surprise me since the barrel is a 1-8 twist. SO I tried some of my 87s and some Sierra 85hp with LVR. To say it liked them would be an understatement!! I shot 5 groups. 3 with 87s and LVR and two with 85hps one with LVR and one with IMR4895. All were 3 shot groups for load testing and all of the groups except for the 4895 shot into the .4s with one group going .242 It did not like the 4895 for some reason and it was a good 100fps slower then the LVR loads. Pretty damn happy for the first trip out!!!

 

[fifdynutz]

Had a shot out Ruger RPR 6mm Proof SS barrel,. It went south and started throwing rounds past 600 so I pulled it. On a normal rifle I would have set it back and shot it some more since it was not fire cracked just the throat was gone. SO to make a long story short I talked to my smith about cutting both ends off of it and making me an AR 6mmARC barrel!! I just got it back and put together and took it out to try out. Factory was around 1.1 to 1.2 but this did not surprise me since the barrel is a 1-8 twist. SO I tried some of my 87s and some Sierra 85hp with LVR. To say it liked them would be an understatement!! I shot 5 groups. 3 with 87s and LVR and two with 85hps one with LVR and one with IMR4895. All were 3 shot groups for load testing and all of the groups except for the 4895 shot into the .4s with one group going .242 It did not like the 4895 for some reason and it was a good 100fps slower then the LVR loads. Pretty damn happy for the first trip out!!!

What was your load data with the imr4895?

 

[Yondering]

Had a shot out Ruger RPR 6mm Proof SS barrel,. It went south and started throwing rounds past 600 so I pulled it. On a normal rifle I would have set it back and shot it some more since it was not fire cracked just the throat was gone. SO to make a long story short I talked to my smith about cutting both ends off of it and making me an AR 6mmARC barrel!! I just got it back and put together and took it out to try out. Factory was around 1.1 to 1.2 but this did not surprise me since the barrel is a 1-8 twist. SO I tried some of my 87s and some Sierra 85hp with LVR. To say it liked them would be an understatement!! I shot 5 groups. 3 with 87s and LVR and two with 85hps one with LVR and one with IMR4895. All were 3 shot groups for load testing and all of the groups except for the 4895 shot into the .4s with one group going .242 It did not like the 4895 for some reason and it was a good 100fps slower then the LVR loads. Pretty damn happy for the first trip out!!!

That 1:8 twist should be good to go for any common bullets up to 105gr; that’s what most of us were using for the 6mm Grendel wildcats for years. All three of mine are 1:8 twist and shoot really well with the Hornady 105gr BTHP or 105 Match Burner.

 

[raptor99]

What was your load data with the imr4895?

28grs I believe.....

 

[LRBuck]

No, that Hornady data is for an 18” barrel, not 22”.
That’s what I was trying to point out to you earlier.

I see that. I was not writing clearly. I do see the Hornady test barrel was listed as 18” Noveske model M4.

The velocity I referred to (2695) was the velocity Hornady listed for 29.7 g of Lever in the 22” barrel on that same page. I assumed they tested at that length, but maybe not?

https://www.hornady.com/assets/site/hornady/files/load-data/6mm-ARC-gas-108-110gr-data.pdf

Anyway, very pleased with it so far and I very much appreciate all the information and help I get from the posts on this thread. This cartridge is my first foray into reloading and while it has certainly been frustrating at moments, I would probably still be cussin’ and breaking things if I didn’t have this as resource.

 

[j-dubya]

Powder Valley just posted Lever. Out of stock already, but they’ll likely post another round later this afternoon.

 

[SBRSarge]

Midway has the Black for 34/box.

Hornady Black 6mm Advanced Rifle Cartridge (6mm ARC) Ammo 105 Grain

Hornady BLACK ammunition features versatile loads optimized for excellent performance from America’s favorite guns. Loaded with legendary Hornady...

www.midwayusa.com

 

[SBRSarge]

I just built my 12” on the SixFiveArms.com Monster barrel.

The black shot a 1.5” group at 100yds and the ELD-M shot .95” I am happy so far, especially for the priceand the fact that I was using a 4x scope.

The 18” Odin averaged .75” this outing. It seems to print tighter groups each trip.

 

[Ledzep]

@Gtscotty Hoping with careful loading, my Odin will preform as well as yours is showing

Side note, tossed the 40 pieces of once fire Hornady 108 M from the initial sight in and function testing in the Thumbler. A bit of a surprise as around a third of the brass exhibited that slight 'Grendel Belt' discussed, measuring in at just under .001. Suppose I had forgotten what suspect brass they make in Nebraska, learned that about ten years ago fooling with Hornady cases in another project. Thinking I should start looking for some Lapua 220 to convert, and eagerly awaiting other brass manufactures to jump on board with the caliber.


View attachment 7592175View attachment 7592176

As a couple others have said, I think you have the opposite of a belt. It's always hard to tell by a single picture but I'm going to guess that if you measure above and below the 'line', the area below measures smaller than the area above. It's from the new cases being smaller in diameter than your chamber, and the top part swelling to match the chamber wall during firing.

 

[raptor99]

Speaking of .220 Russian case, has anyone formed 6ARC from the .220 brass?? If so what is the process?? And what all has to be done to get it ready to shoot?? I have a bunch of cases that are more or less junk from the damn "Grendel belt"........

 

[George Mac]

SBRSarge thanks for that update on the 12” from SixFiveArms. I ordered one as well. If you have velocity data for the 108’s and 105’s I’d love to hear it. Thanks.

 

[SBRSarge]

SBRSarge thanks for that update on the 12” from SixFiveArms. I ordered one as well. If you have velocity data for the 108’s and 105’s I’d love to hear it. Thanks.

I only shot one five shot group with each type of ammo, so the sample size is statistically very small, but here is what I got.

Group Sizes:
105 gr Black 1.5”.
108 gr ELD-M .95”.

Velocities;
Black 2395 w/ S.D. 37.0 (might explain the larger group!)
ELD-M 2396 w S.D. 12.7


For comparison, out of my 18” barrel velocities were;
105 gr Black 2615
108 gr ELD-M. 2621

 

[raptor99]

Ok guys, I have a question for the experts, why the hell am I getting ejector marks on brand new FACTORY loads!!!! Not only that the brass is now JUNK!! I can damn near push the primer in with my thumb!! I am using a can but that should not make a difference and I have not had this issue before shooting the factory loads!!! I am really getting frustrated with this damn caliber. I love it but brass just sucks!! I am now using LVR and am at least a grain to grain and a half below max load. I am still having issues when sizing my brass. Even though I don't get the "Belt" but when the brass is resized it will chamber but I can NOT eject it. I have to use a hammer handle and bang the stock on the floor to eject the brass.. The base of the case is .440 to .441 after sizing. I ordered a small base die but it has not even shipped yet. I am at my wits end trying to figure this damn thing out!!

 

[Ledzep]

Ok guys, I have a question for the experts, why the hell am I getting ejector marks on brand new FACTORY loads!!!! Not only that the brass is now JUNK!! I can damn near push the primer in with my thumb!! I am using a can but that should not make a difference and I have not had this issue before shooting the factory loads!!! I am really getting frustrated with this damn caliber. I love it but brass just sucks!! I am now using LVR and am at least a grain to grain and a half below max load. I am still having issues when sizing my brass. Even though I don't get the "Belt" but when the brass is resized it will chamber but I can NOT eject it. I have to use a hammer handle and bang the stock on the floor to eject the brass.. The base of the case is .440 to .441 after sizing. I ordered a small base die but it has not even shipped yet. I am at my wits end trying to figure this damn thing out!!

Ejector swipe and loose primer pocket sounds like excessive pressure. Often times the ejector swipe can be fixed with an adjustable gas block. I don't know if it will solve the loose primer pockets. I've been running 60-65ksi loads in my bolt gun for 8-10+ loadings and they're holding up great so I don't think it's the brass (Hornady 6mm ARC brass-- if you're using something else I can't speak for that).

Sticking resized cases is a head space thing most of the time. Get a comparator gauge and measure the shoulder before and after sizing. I like to decap the case before measuring the "as fired" cases, and file off any burrs from ejector swipe, extractors, etc... so you get a legit reading. With AR's I usually do a .002" bump then check a batch of 10 to make sure they all eject easily, if not I run the die down until they do.

 

[raptor99]

Ejector swipe and loose primer pocket sounds like excessive pressure. Often times the ejector swipe can be fixed with an adjustable gas block. I don't know if it will solve the loose primer pockets. I've been running 60-65ksi loads in my bolt gun for 8-10+ loadings and they're holding up great so I don't think it's the brass (Hornady 6mm ARC brass-- if you're using something else I can't speak for that).

Sticking resized cases is a head space thing most of the time. Get a comparator gauge and measure the shoulder before and after sizing. I like to decap the case before measuring the "as fired" cases, and file off any burrs from ejector swipe, extractors, etc... so you get a legit reading. With AR's I usually do a .002" bump then check a batch of 10 to make sure they all eject easily, if not I run the die down until they do.

I could understand if it was my reloads since I did have issues with my Varget loads and finally just gave up on Varget. But this is FACTORY Hornady ammo!!! Junk after one firing!!!

 

[Ledzep]

Right. What I'm getting at is unless QC slipped and they loaded hot ammo (not impossible, but fairly rare), something in your rifle is causing timing (gas system) or pressure (fouling) problems. I'd give the barrel a good scrub and try adjustable gas.