Yes, thanks for posting this, I recently pick up an 8# Keg of AR Comp, I have been looking for starting charge weight for my 18'' 1&8 barrel and my 24'' tube with this powder, My 11th Edi of the Hornady manual doesn't show this powder at all!
Not quite sure how youre managing to get your loads much beyond 27.4-27.5 without very heavy compression and though you may not be seeing pressure signs in your brass, your primer pockets may tell a different story. I have several 20 barrels (Proof, Wilson Combat and Bartlein) that run low SD and 2550fps at 27.0 in Hornady brass with CCI450s with 120gr Scenars. Your choice of course, but 29+ seems way over any sensible max load.
Thanks for posting guys! I'm glad I'm still searching for load data on this powder, most load data I see is at 26 to 27.5gns for AR Comp, I'm planning to develop a load with my 18' 1&8 twist barrel, I thought some of the loads here seemed a bit high above 27.5gns JMO
130 ELD
AR Comp
Grains FPS
25.0 2251
25.2 2253
25.4 2283
25.6 2298
25.8 2308
26.0 2335, 2327
26.2 2345, 2344
26.4 2352, 2357 [COLOR="#FF8C00"]26.6 2385, 2383
26.8 2396, 2399[/COLOR] 27.0 2399 [COLOR="#FF0000"]27.2 2426
27.4 2433
27.6 2459
27.8 2466
28.0 2476
28.2 2498
28.4 2520
28.6 2527
28.8 2540
29.0 2556
29.2 2570
29.4 2573
29.6 2593
29.8 2621
[/COLOR]
I didn't see any pressure signs on the 130s. The 120s were likely closer to the lands and started showing pressure in the 29s.
I bolded and color-coded based on pressure. Notice the 42fps jump from 28.2gr to 28.4gr with the 120gr ELD-M, which is a major departure from the trend line, followed by a slight velocity decrease with a charge weight increase.
Also notice the departure from the trend under the 130gr, where you saw ~30fps increase between 26.4gr and 26.6gr.
These are the things I look for when doing pressure ladders like this.
For 120gr ELD-M, if it were my rifle, I wouldnt load over 27.8gr of AR Comp.
For the 130gr ELD-M, I wouldnt load more than 26.4gr, unless there is room to extend your COL some.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
02-04-2023, 04:18 PM (This post was last modified: 02-04-2023, 10:18 PM by Harpoon1.)
AR-180 Wrote:Every conversation on reloading says to start low and work up. It is often said that each gun is different. Thats why we perform load development.
These data are what I found doing load development for one particular gun.
That is true, however, your gun most likely doesnt deviate that much from all the other SAAMI spec Grendel ARs, there maybe +/- several tenths of a grain latitude between individual guns but, its clear from some of those FPS numbers, youre exceeding the SAAMI spec pressure limits! And in some cases, by quite a bit!
Looking for pressure signs only as a limiting factor in an AR Grendel is usually futile and a crap shoot because of its lower operating pressure limits, the chronograph is your friend. Bolt guns are another matter, you have higher PSI limits to work with and the classic pressure signs can be more diagnostic.
Pages 20-23 & 35 are worth a look. And those are the PDF page numbers, not the number at the bottom of the individual page.
02-04-2023, 10:04 PM (This post was last modified: 02-04-2023, 10:07 PM by Bobke.)
Its been very strongly suggested that a far more reasonable max be observed when loading AR Comp, and wanted to document how much case capacity these loads appear to consume. Also wondering how much compression would be required in doing so. Additionally, how consistent could you possibly hold either loaded OAL or distance to lands with the powder column trying to push the bullet back out of the case. And nothing to confirm true pressure, beyond casual review of case condition.
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Bobke, I agree! I just loaded 2 loads of AR Comp, 27.1gns and 27.4gns, both loads in new Starline unfired brass, and both IMO were about a compressed load, yes, I tried to tap the powder down to settle, but IMO I don't think your gonna stuff much more powder in these cases without being totally compressed, I know all about different brass can hold more or even fired cases of Starline can hold a tic more but from what I see your not going to put to much more powder in the cases with AR Comp without serious crunch!!!! and I try to stay away from compressed loads!!! Cold and windy here again so hopefully I can get out and shoot next weekend, I'll post my results from my range trip,
AR-180 Wrote:Every conversation on reloading says to start low and work up. It is often said that each gun is different. Thats why we perform load development.
These data are what I found doing load development for one particular gun.
Just keep in mind that the #1 indicator of pressure is velocity.
When you see velocity and charge weights that much higher than the max, its indicative of pressures that have exceeded safe levels.
Your 120gr load went up 150 fps above max.
Your 130gr max load is 264 fps over where it departed from the trend line at 2357fps.
If you look at AR Comp on a burn rate chart, you see why we advocate for hand loaders to be careful with it.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
