Hey. I picked up a CMMG 6mm ARC 20" (Endeavor 300 series) AR-15 this year and am in process of developing loads for it. I also just purchased and am learning the QuickLoad software.
I'm using the Hornady 108g ELD Match bullet and Varget.
Hornady lists a starting load of 24.5 (2,200 FPS) and max load of 27.2 (2,450 FPS).
When I model the max load of 27.2 QuickLoad shows that as way over max pressure at 59,033 psi. Gas gun maximum pressure is 52,000 psi. So this surprises me and makes me wonder that maybe I'm using QuickLoad incorrectly or is it simply inaccurate when estimating pressure or is Hornady publishing loads that are over pressure?
According to QuickLoad I'd have to reduce the Varget charge from 27.2 to 26.05 to get under the 52,000 psi limit.
QuickLoad has the 6mm ARC cartridge at 34.5g water max case capacity. I've read that it might actually be 34. If I change QuickLoad to 34 it estimate the pressure even higher. I haven't measure my Hornady factory brass for capacity.
Any theories on this or experience using 6mm ARC in QuickLoad and have suggestions for improving the QuickLoad results?
I'll include a screen shot of my QuickLoad settings and here's a link to image in case it doesn't show up here.
Hmmm. That's funny the gas gun Hornady load data I have 1) only goes up to the 105, 2) lists varget for that bullet as 24.2 (2200) to 27.0 (2450). Unless there's more Hornady data, this was released with the release of the 6Arc.
So even if you use the 108 you're liable to get only 2400 under these circumstances with Varget. It is a relatively big kernel for the 6Arc case. ps, do a seat-to-lands measurement also with an OAL chamber gauge and modified case. Guys have been known to stick the bullet in the lands and make a powder mess getting it unstuck.
When I model the 108/varget in my grt - which differs from QL -- I do not show over pressure.
All that being said, QL is known to be first of all, needing of lots of tweaks to set up for your gun, and second, it has trouble modeling short, fat AR cartridges like grendel and 6Arc (which is derived from the grendel). This is a well-known talked about feature on 65 Grendel forum.
I will admit I am not expert in QL, I find it too hi-maint for my personal tastes. The users on the 65 forum that do use it have worked on their models for quite a bit, and use it only as a guide at that.
Best way for you to do load development is to start out low and increase your loads in a 0.2-0.3 gr increment. Watch for pressure signs. And do it over a chrony. That way you will know what your rifle/barrel will do. I would advise starting at low, 24.2 but IMO the first grain doesn't give you much useful data... but starting no higher than 25.0. Get a ladder for your case, primer, powder lot, seating depth and chamber specs and barrel performance. The real thing is better than anyone's data model.
11-04-2021, 07:53 AM (This post was last modified: 11-04-2021, 07:55 AM by r.tenorio671.)
...here's the Hornady Gas gun data for 108-110 bullets (ELD-M and A-Tip). I suspect you could also use this data for the Sierra SMK 110, just work your charge weight up per normal...
Looking at these pdf's (thanks RT!) the 108 and Varget, max load is 26.7 at AOL of 2.260 and a Fed 205 primer, not 27.2. btw I don't recall which primer you are using... any of these components can cause a difference (even powder lot differences), plus the original comment, that QL is more of a guide than a definitive, all put the loads in the ballpark but working up is still a necessity.
One more thing, typically a barrel needs ~100 rounds to break in, by that I mean that MV's tend to gain ~50 fps after about 100 rounds, probably due to hot gasses shaping the throat area.
So several variables are still in play for you.
Start low, work up, be observant.
11-04-2021, 05:53 PM (This post was last modified: 11-04-2021, 05:57 PM by Patrickb4365.)
(11-03-2021, 11:55 PM)grayfox Wrote: Hmmm. That's funny the gas gun Hornady load data I have 1) only goes up to the 105, 2) lists varget for that bullet as 24.2 (2200) to 27.0 (2450). Unless there's more Hornady data, this was released with the release of the 6Arc.
So even if you use the 108 you're liable to get only 2400 under these circumstances with Varget. It is a relatively big kernel for the 6Arc case. ps, do a seat-to-lands measurement also with an OAL chamber gauge and modified case. Guys have been known to stick the bullet in the lands and make a powder mess getting it unstuck.
When I model the 108/varget in my grt - which differs from QL -- I do not show over pressure.
All that being said, QL is known to be first of all, needing of lots of tweaks to set up for your gun, and second, it has trouble modeling short, fat AR cartridges like grendel and 6Arc (which is derived from the grendel). This is a well-known talked about feature on 65 Grendel forum.
I will admit I am not expert in QL, I find it too hi-maint for my personal tastes. The users on the 65 forum that do use it have worked on their models for quite a bit, and use it only as a guide at that.
Best way for you to do load development is to start out low and increase your loads in a 0.2-0.3 gr increment. Watch for pressure signs. And do it over a chrony. That way you will know what your rifle/barrel will do. I would advise starting at low, 24.2 but IMO the first grain doesn't give you much useful data... but starting no higher than 25.0. Get a ladder for your case, primer, powder lot, seating depth and chamber specs and barrel performance. The real thing is better than anyone's data model.
(11-04-2021, 07:53 AM)r.tenorio671 Wrote: ...here's the Hornady Gas gun data for 108-110 bullets (ELD-M and A-Tip). I suspect you could also use this data for the Sierra SMK 110, just work your charge weight up per normal...
That's very interesting. My data is from Hornady's online app and should be their most recent. See attached pic showing screen shot of the app with Varget going up to 27.2. Even if I drop down to the 26.7 Quickload still shows it over pressure at 56,295 psi.
I am by no means solely relying on Quickload. I'm not relying on it at all in fact because I just got it and am learning it. I do work up loads and look for pressure, etc. However this 6mm ARC load is limited by the pressure on the bolt not the pressure on the brass so I'm particularly interested in what pressure's I'm generating aside from what you normally would be able to look for and detect by inspecting brass. I have no way to measure pressure so that's why I was interested in QuickLoad.
(11-03-2021, 11:55 PM)grayfox Wrote: Hmmm. That's funny the gas gun Hornady load data I have 1) only goes up to the 105, 2) lists varget for that bullet as 24.2 (2200) to 27.0 (2450). Unless there's more Hornady data, this was released with the release of the 6Arc.
So even if you use the 108 you're liable to get only 2400 under these circumstances with Varget. It is a relatively big kernel for the 6Arc case. ps, do a seat-to-lands measurement also with an OAL chamber gauge and modified case. Guys have been known to stick the bullet in the lands and make a powder mess getting it unstuck.
When I model the 108/varget in my grt - which differs from QL -- I do not show over pressure.
All that being said, QL is known to be first of all, needing of lots of tweaks to set up for your gun, and second, it has trouble modeling short, fat AR cartridges like grendel and 6Arc (which is derived from the grendel). This is a well-known talked about feature on 65 Grendel forum.
I will admit I am not expert in QL, I find it too hi-maint for my personal tastes. The users on the 65 forum that do use it have worked on their models for quite a bit, and use it only as a guide at that.
Best way for you to do load development is to start out low and increase your loads in a 0.2-0.3 gr increment. Watch for pressure signs. And do it over a chrony. That way you will know what your rifle/barrel will do. I would advise starting at low, 24.2 but IMO the first grain doesn't give you much useful data... but starting no higher than 25.0. Get a ladder for your case, primer, powder lot, seating depth and chamber specs and barrel performance. The real thing is better than anyone's data model.
Thanks. I think I'm doing all your suggestions. I do appreciate the information and advise.
Interesting that their app shows a different max even from the hdy 10th. Well.
Out of curiousity I looked up data from the Hodgdon book/mag, it has the sierra 107 using varget, 25.8 compr and 51.6 ksi.
Would you want to try a better powder? Lever, CFE, even Staball is in there for the Hodg data... ball powders work better due to the smallish case capactity.
Don't think I've tried varget for any 6Arc except down in the 90 gr area.
...FWIW, manufacturer posted load data ALWAYS carries the caveats about using the info as a "guide" and cautions with "start low & work up". As many have found over the years of their reloading experience, each barrel behaves differently and it is only through testing can one arrive at a preferred load. If ones component inventory is limited, start around the middle range of the published data and load only 3 rounds of each charge in the range you decide on, the 3 rounds will be enough to determine if you are exceeding pressure ranges for YOUR barrel. After that then you will have a more defined direction to proceed your load development with... I know, preaching to the choir but it's still useful info for the newer reloaders lurking in the silent shadows...
I have never had an issue using Hornady load data, it is pretty much been my go to for loading this round for load development.
Some of my gas gun brass has been loaded 12 times, the only thing I have noticed is the primer pocket seems to be starting to get loose. But I have yet to pop a primer, or crack a case.
I better go knock on some wood, I'm going to the range this weekend.
If you can not see the tyranny of having a gun ban enforced by men with guns... Then you fail to understand why the second amendment was written in the first place.
(11-04-2021, 09:01 PM)grayfox Wrote: Interesting that their app shows a different max even from the hdy 10th. Well.
Out of curiousity I looked up data from the Hodgdon book/mag, it has the sierra 107 using varget, 25.8 compr and 51.6 ksi.
Would you want to try a better powder? Lever, CFE, even Staball is in there for the Hodg data... ball powders work better due to the smallish case capactity.
Don't think I've tried varget for any 6Arc except down in the 90 gr area.
I'm mainly using Varget now because it's reputation for temperature stability and Horndady has the published data and I actually had some on hand. I'm willing to give up some velocity for consistent velocities throughout different times of the year. I'm in Kentucky and we definitely have 4 seasons of weather. I dont shoot much in Winter. I would love to truly know how Staball compares to Varget in termperature stability from 45-95 degrees temperature.
My goal with 6mm ARC in the AR-15 is to shoot IPSC steel targets at 1000 yards and hit more times than I miss. I think I really only need 2300 FPS with the Hornady 108 grain ELD Match bullet to stay supersonic to 1000 yards but obviously the more velocity the better to help with wind. I was thinking Varget might do the job and be really consistent in velocity throughout the year.
11-05-2021, 10:45 PM (This post was last modified: 11-05-2021, 10:53 PM by StoneHendge.)
Great minds think alike, Patrick. I've been using Varget with 105 gr RDF's in a 16" Lilja since March here in Phoenix. I put a velocity of 2446 in my Kestrel in March and my dope has been spot on (even when I'm not) in my monthly AR match out to 700, from chilly March mornings in the 50s to getting over 100 as noon approaches in the summer. Several spring matches had a 30 degree temp delta between first and last stages, but my dope and zero never noticed. Conversely, I shot a match with my Grendel with CFE the summer before last and it was a disaster. It was one of 4 cloudy days that summer and 20 degrees "cooler" than expected. My velocity dropped about 40 fps, my zero shifted, and a 1/2 MOA load opened up to close to 2 MOA. I had to bite my tongue like I often do when ball powders were referred to as "better" above. They may be better for AR-15 hunting distances, but not for target shooting. And with all the small groups with high velocities and low sd's with ball powders I've seen on the interwebs, I can't recall more than one or two that were clustered around the aiming point, which is the mark of repeatability.
FWIW, I was at 26.8 grains in a Starline Grendel case with a Hornady sizer die to get the 2446. That was as high as I could go. I switched to the RCBS small base sizer and am at 26.5 grains now. I got an occasional ejector mark from timing (my 16" is a middie) with the old load but strangely, I haven't yet with the base sized load.
My sugestion is stop using QL... Bad data in is only going to give bad data out. I do not know of one single individual QL in the Grendel or ARC worlds that has got good data out of it. You will waste lots of time and $$$ chasing your tail. You would be better off educating yourself on proper load development, and time and money ahead. As I have stated before I have used Honady load data as a base load for all my ARC load development and have had zero problems. I have had more problems with Honady factory loads than my own loads. I have been working this platform since it was released. My first rifle was on the range 2 weeks after the release. I now have 4 rifles in different configuration and have worked with 7 different platforms of it. Me and my son have been at this since the beginning.
Proper education and knowledge will be your friend in this adventure. Believe me you can be smarter than a computer program or App. Every gun will give you different results, something QL will never be able to calculate.
If you can not see the tyranny of having a gun ban enforced by men with guns... Then you fail to understand why the second amendment was written in the first place.
(11-04-2021, 09:01 PM)grayfox Wrote: Interesting that their app shows a different max even from the hdy 10th. Well.
Out of curiousity I looked up data from the Hodgdon book/mag, it has the sierra 107 using varget, 25.8 compr and 51.6 ksi.
Would you want to try a better powder? Lever, CFE, even Staball is in there for the Hodg data... ball powders work better due to the smallish case capactity.
Don't think I've tried varget for any 6Arc except down in the 90 gr area.
I'm mainly using Varget now because it's reputation for temperature stability and Horndady has the published data and I actually had some on hand. I'm willing to give up some velocity for consistent velocities throughout different times of the year. I'm in Kentucky and we definitely have 4 seasons of weather. I dont shoot much in Winter. I would love to truly know how Staball compares to Varget in termperature stability from 45-95 degrees temperature.
My goal with 6mm ARC in the AR-15 is to shoot IPSC steel targets at 1000 yards and hit more times than I miss. I think I really only need 2300 FPS with the Hornady 108 grain ELD Match bullet to stay supersonic to 1000 yards but obviously the more velocity the better to help with wind. I was thinking Varget might do the job and be really consistent in velocity throughout the year.
....the JBM Ballisitics web site will give you a good idea if that HDY 108 @2300 FPS will achieve your goal @1K yds. Just pick the bullet from the drop-down menu, plug in the speed and check the box for "Mark Sound Barrier Crossing" to show where supersonic transition occurs. You can plug in the other variables as well to further refine the calculations. YMMV
11-06-2021, 09:42 PM (This post was last modified: 11-06-2021, 09:53 PM by Patrickb4365.)
(11-06-2021, 01:25 AM)r.tenorio671 Wrote:
(11-05-2021, 02:34 PM)Patrickb4365 Wrote:
(11-04-2021, 09:01 PM)grayfox Wrote: Interesting that their app shows a different max even from the hdy 10th. Well.
Out of curiousity I looked up data from the Hodgdon book/mag, it has the sierra 107 using varget, 25.8 compr and 51.6 ksi.
Would you want to try a better powder? Lever, CFE, even Staball is in there for the Hodg data... ball powders work better due to the smallish case capactity.
Don't think I've tried varget for any 6Arc except down in the 90 gr area.
I'm mainly using Varget now because it's reputation for temperature stability and Horndady has the published data and I actually had some on hand. I'm willing to give up some velocity for consistent velocities throughout different times of the year. I'm in Kentucky and we definitely have 4 seasons of weather. I dont shoot much in Winter. I would love to truly know how Staball compares to Varget in termperature stability from 45-95 degrees temperature.
My goal with 6mm ARC in the AR-15 is to shoot IPSC steel targets at 1000 yards and hit more times than I miss. I think I really only need 2300 FPS with the Hornady 108 grain ELD Match bullet to stay supersonic to 1000 yards but obviously the more velocity the better to help with wind. I was thinking Varget might do the job and be really consistent in velocity throughout the year.
....the JBM Ballisitics web site will give you a good idea if that HDY 108 @2300 FPS will achieve your goal @1K yds. Just pick the bullet from the drop-down menu, plug in the speed and check the box for "Mark Sound Barrier Crossing" to show where supersonic transition occurs. You can plug in the other variables as well to further refine the calculations. YMMV
Thanks. I don't think I have seen that site. But I have been using the Ballistic Explorer software (http://www.dexadine.com/index.html) for several years and have found it to be extremely accurate. I really like it and recommend it.
(11-06-2021, 12:05 AM)Dino11 Wrote: My sugestion is stop using QL... Bad data in is only going to give bad data out. I do not know of one single individual QL in the Grendel or ARC worlds that has got good data out of it. You will waste lots of time and $$$ chasing your tail. You would be better off educating yourself on proper load development, and time and money ahead. As I have stated before I have used Honady load data as a base load for all my ARC load development and have had zero problems. I have had more problems with Honady factory loads than my own loads. I have been working this platform since it was released. My first rifle was on the range 2 weeks after the release. I now have 4 rifles in different configuration and have worked with 7 different platforms of it. Me and my son have been at this since the beginning.
Proper education and knowledge will be your friend in this adventure. Believe me you can be smarter than a computer program or App. Every gun will give you different results, something QL will never be able to calculate.
Thanks. I'm not really using QuickLoad. I just purchased it and am looking at it to see if it would be an additional tool for helping with predictions especially with pressure. I would never solely trust it to develop loads.
As I understand it 6mm ARC in AR15 is limited by pressure that the bolt can safely handle. So if I'm are seeing pressure signs on brass I am probably over pressure for the bolt. Those pressures would be fine for the brass and for bolt action rifles. So simply identifying pressure signs on brass isn't as reliable for AR15 to make judgements on how safe my 6mm ARC loads are.
Just about everything I shoot I load, about 15K rounds a year, really the only time I shoot factory loads is if I need brass, like in the case with the ARC. I can't believe that Hornady has not made any affordable brass to the public since the release of this round. Some but very little has been available. I have to start a rotation on some of my ARC brass pretty soon, some of the primer pockets are starting to get loose. I have 1K of new Starline Grendel brass to process. But that is going to be a long process because of all the trimming and at least one fire form. At least I have a couple thousand 100 grain pulls I got from American Reloading that they screwed up the points pulling them, they did send me good replacements and told me to keep the bad ones, might as well put them to good use. Surprising they still hold some accuracy though, my son loves shooting them at steel plate.
If you can not see the tyranny of having a gun ban enforced by men with guns... Then you fail to understand why the second amendment was written in the first place.
I'll tell you from a very recent experience something QL can't predict. I had a timing issue that appeared to be a pressure issue when doing a load work up with 26gr of H4895....when I hit 26.5 which is still very reasonable, I got a bulge in some cases. Mild belting and even hairline cracks.
I don't know for sure what the reason was but I believe it was overpassed since bleeding more gas when suppressed made that issue go away and I'm reliably pushing 26.5 this weekend as we speak. Slow, but accurate and not damaging cases anymore. No other changes except more rounds down the pipe.
Just my recent experience with what I thought was pressure from a particular load.
Quickload is a useful starting guide in absence of published data. I use it but I tend to only use it for confirmation, I would never use it alone. Wildcats and small case volumes can bring it undone but bread and but stuff like 243, 308 etc work well. Remember your components arent the same as what Hornady used when they determined their data but I have found it to be bloody close.
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