One thought has occurred to me from time to time on this topic of temp sensitive powder... maybe that sensitivity differs for different cartridges. And especially the question arises, what about the more, say, efficient cartridge cases.... comes up now because of the powders hornady lists, the ones giving us the MV are ball types like cfe, lever and 2520. Could it be that cfe is less sensitive for this more efficient case.. might even be true comparing 308 case vs say the creed.... anyway, maybe others have some ideas on this.
A interesting topic to me. Of note are that the heat of the firearm it's self, separate from the ammo can increase velocities. Also unknown is the temp sensitivities of primers.
Another question is what does the copper reducing agent do to the pressure curve? Does less copper = more speed or less speed?
08-09-2020, 12:25 PM (This post was last modified: 08-09-2020, 12:33 PM by VASCAR2.)
I find it interesting that Hornady list the same maximum velocity for the 108-110 bullets using H4895, IMR8208XBR and Varget at 2400 FPS out of an 18” 6 ARC AR-15. The CFE223 and Leverevolution show the same velocity of 2575 FPS out of an 18” barrel. The CFE223 powder appears to be the more efficient with 29.1 grains whereas LVR needs 29.7 grains to get the same velocity.
H4895 and IMR8208 max out at 25.2 and 25.3 grains of powder with the same 108-110 grain bullet. With 175 FPS velocity advantage I think CFE223 would be worth testing in various temperatures. It would be intersting to see if CFE223 looses approximately 1 FPS per degree as has been published.
The difference in volume and bore diameter could have an effect on temperature sensitivity because there appears to be a different pressure curve between the 6.5 Grendel and 6 ARC. Will the slightly less case capacity of the 6 ARC and pressure curve affect the temperature sensitivity of CFE223. The main factor to me involving temperature sensitive powders is the change in zero in cold temperatures compared to warmer temperatures where I do most of my shooting. I don’t hunt enough at longer distances for the change in velocity to have a significant effect on bullet performance in the target.
Looking at the burn rate chart : http://bulletin.accurateshooter.com/2020...3-powders/
#108 Varget
#109 Win 748
#110 Blc(2)
#111 CFE 223
#112 Power pro 2000
#113 Lever
#114 H380
This group looks to be good candidates for the heavy (103-110) bullets. For my PPC I like CFE 223 and Lever the best so far and Blc(2) will be on the short list for the future.
I would like to see what H380 would do as I am wanting to see the results of the slowest burn rate powder in the bunch.
RL 17? check out range report from 6.5 grendel site (6 AR with long bbl) http://www.65grendel.com/forum/showthrea...R&p=266913
Burn rate much slower than I would have tried. I have some so I'll see what it will do.
I------ don't think so for the 6Arc. It's at least 1.5 grs shy of the capacity of the 6 AR, right? And R17 works well for 140-ish bullets in the 6.5 Creed, some 130's too for me. I'd think too slow for our uses here.
Besides it's not known for temp stability... not like the H4350 standards.
Since H4895 wasn't quite the choice (so far) maybe look at I-4895.
(08-14-2020, 09:01 PM)Lemonaid Wrote: RL 17? check out range report from 6.5 grendel site (6 AR with long bbl) http://www.65grendel.com/forum/showthrea...R&p=266913
Burn rate much slower than I would have tried. I have some so I'll see what it will do.
The OP is using a 28" barrel. Would that make a difference? More time for the slower powder to work it's magic?
I reloaded a few rounds with RL 17. I can get 27.7 grains to fit in my PPC cases without compression using a Sierra 107 MK seated to 2.280" (.010 jump). 24 inch barrel, Fed 205 primers.
Results from today's range trip.
26.5=2476
26.7=2509
26.9=2509
27.1=2546
27.3=2572
27.5=2583
27.7=2648
Very minor cratering on primers at upper loads nothing troubling. Accuracy was average, all seven rounds in 1.5 inches at 100 yards.
So it's viable but not optimal. For my gun it's giving about the same velocity at the same charge weight as CFE 223 but I can't fit as much in the case.
08-16-2020, 04:11 AM (This post was last modified: 08-16-2020, 04:13 AM by grayfox.)
Well, you might be on to something after all, that’s ppc so 6arc has a bit more room...
Looking at your data points, to smooth them a bit I look at 0.4 gr deltas, several are ~40 ft/s for a 0.4 increase, which is an expectation. But the last jump to 27.7 is large, don’t have a graph in front of me but that might signify you reached a max.
Next thought... ok it’s past midnite here so brain is foggy... but 2648 for a 24” barrel... kind of low? I don’t shoot ppc so I could be wrong here.
Do you think the 6arc could get 28.5-29 maybe loaded? Or would be too hot? What does the horde think.
By the way Selway. Armory .com has some powders. Ar comp, 2520, a few others. More than many of the sites I looked at.
grayfox, Hodgdon lists 2702 velocity for 28.5 grains of CFE 223 as max and that is the highest one on their list. The next best is 26.8 compressed of H4895 at 2631, so RL17 is a contender.
The 27.7 load in my case, my rifle is at the edge of being compressed, and is possibly very lightly compressed and that may be indicated by the velocity spike.
As for ARC case capacity, it will also depend on where the bullet touches the lands on how much powder room is available so you would have to do an individual test to see how much powder you can fit in your cases. If you have some RL 17 and a fired case, and some 105's 107's or 108's let me know what you find out. The 108 ELD M would only permit 26.5 grains of RL 17 at 2.270" for me.
08-16-2020, 09:42 PM (This post was last modified: 08-16-2020, 09:50 PM by grayfox.)
I have a few cases. Might do this, you know, an extra little project.
105s. Think I will fill to base of neck, see what #grs that is for some of these.
1x fired and resized.
Ok. So I resized and primed my new, 1x hornady's from the 105 factory I shot couple of days ago.
Then did a measured fill for 6 powders into them and measured the capacity for each powder to the base of the cartridge neck:
RL17 - 29.8grs
AR Comp (Arc) - 28.0
RL15 - 29.2
8208xbr - 29.8
I-4350 - 28.8
H-4895 - 28.3
If my picture-thingy works I will have a couple of pics of the powder/cases.
(Bft - I HATE this picture-posting thing in this forum!!!)
Thanks for the info grayfox. For comparison my case up to the neck of RL 17 is 29.3. Using a Sierra 107MK and the fired unsized case I could only get to 27.7 grains to be under mag length and not into the lands (2.290 touches lands) and not compressed.
As I am shooting a bolt action, I don't have to be concerned with how the burn rate effects port pressures and how it cycles, dwell time and such. RL 17 might fail for semi-autos.
(08-17-2020, 01:13 AM)grayfox Wrote: Those capacities, 29.3, 27.7... these are for your ppc, right?
Correct. From what I could tell from the blueprints there didn't seem to be a lot of difference between the ARC and the PPC so there should be similar results, as with the 6 AR. They all have the same mother but different fathers, so step children?
brothers, just ate different amounts of wheaties when they were growing up!!!
I think the 6Arc has a bit more room in the case, it's in between the ppc and the 6Ar.
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I'm going to look for some PP2000 tomorrow.
[/quote]
I have tested PP2000 recently and chose it as my load for my 105gr Berger VLD Targets and Hunters.
I did a velocity test...ish with the VLD Targets. I set one mag of 5 in a freezer (30-32°F) for about 5 hours and the other sat on the dash for about an hour while on a 99°F day. I grabbed the one on the dash and it was rather painful to grab, but no burn marks at all. The hot mag shot 2565 fps with a 0.45" group (SD 11). The cold mag shot 2475 fps with a 1.72" group (SD 35) and did not cycle the gun well. Control was from a 92°F day with a velocity of 2551 fps and a group of 0.70" (SD 10) and I pulled the shot that made it 0.70".
No exact temperature data, but it was still interesting none-the-less.
