Day out Shooting with CFE223, 123gr A-MAX, 107gr SMK 16" Grendel

[LRRPF52]

I've had some batches of safety ladders worked up using CFE to get an idea of where my carbine stands with regard to velocity and consistency with Hodgdon's CFE223.

123gr A-MAX First
I had a suspicion that Hornady's data in the 9th Edition for 120-123gr pills could be based on the least common denominator of the projectile with the most drag in bore and start pressure sensitivity, which is the 120gr GMX solid copper unit.

Two things that steered me in that direction were the data meticulously recorded by Bwild97 here, and Hornady's CFE data for the 129gr SST, which is .5gr higher for the max load compared to the 120-123gr pills.

I already know that my Grendel handles 31.0gr of CFE well behind the 123gr A-MAX, so I wanted to run more extensive testing to see where the charge weight starts to spike.

I loaded 10 incremental charges, with 2 batches of each 10-round sequence. I used the longest COL I could get away with in my chamber and mags, which was

* 2.272"-2.277"
* once-fired Lapua brass
* Remington 7.5 primers
* 123gr A-MAX
* CFE223

Here's where you need to check yourself when viewing this data, because I literally expected to hit bad pressure signs much earlier. Thoroughly examine your experience with hand-loading before considering using any of the below data, especially since I set out to depart from published max loads.

A Chrony Beta Master was used for velocity readings as a potential indicator of pressure spikes, erratic deviations from a trend, or consistent charge weight to velocity increase. The Chronograph was at least 15ft from the muzzle. Temperature was 60 F measured on-site with a thermometer out of the sunlight, next to the shooting position.

Brass was measured before and after shooting, at the case web just above the extractor groove, using dial calipers in order to inspect for case web expansion (serious pressure sign). Before, measurements were consistently .441"-.442" at this location. After each round was fired, the chronograph reading was observed, recorded, and brass inspected visually and with the calipers.

31.1gr 2489 fps case web .441" dia., no ejector swipes, no primer abnormalities
31.4gr 2520 fps same, velocity increase was 31fps
31.7gr 2532 fps same, 12fps increase
32.0gr 2553 fps same, 21fps
32.3gr 2572 fps same, 19fps

At this point, I stopped and double-checked everything, since I was into some unusually fast velocities for a 16" Grendel with a 123gr A-MAX. I had not seen any significant jumps in velocity outside of 31fps at this point, which is consistent with .3gr increments in this case and other powder/projo combos.

I decided to seek the point of departure by pressing forward cautiously.

32.6gr 2598 fps no dimensional change in the web, primer GTG, 26fps increase
32.9gr 2612 fps same, 14fps
33.2gr 2640 fps primer starting to crater, 28fps increase
33.5gr 2698 fps slight cratering again, 58fps spike

At this point, I had found what I was looking for, which was a clear departure from the trend, confirmed with slightly cratered primers. I had to have been well above Grendel SAAMI Maximum Allowable Operating Pressure by then for certain. The question is, when did I exceed that point, and what is a safe load for me?

2698 fps from a 16" Grendel carbine pushing a 123gr A-MAX is some bad ju-ju, and you won't find any industry-tested data from a 24" gun to-date over 2650fps that I'm aware of.

Either way, CFE appears to be some very forgiving powder as to building pressure ideally in the Grendel. I chose not to fire the last round of 33.8gr, because I knew I would have even more of a cratered primer or worse, and I had already exceeded MAOP much earlier.

107gr SMK
I then moved on to my 107gr loads with CFE.

107gr SMK
CFE223
Lapua 1 x fired brass
Rem 7.5 Primer
2.275" COL

Everything went haywire at this point. I could not correlate one charge weight with a sensible velocity at all. I don't know if the Chrony went to lunch, the sun angle made readings skewed, or what. First time I have seen it with this chronograph.

31.5gr 2708 fps no pressure signs on brass or primers, velocity reading WTH?
31.8gr 2522 fps
32.3gr 2526 fps
32.7gr 2658 fps
33.0gr 2750 fps
33.3gr 2575
33.6gr 2672
33.8gr 2668
34.0gr 2757

I don't know if the cartridges were rearranged in my case, or got somehow out of sequence, but the brass was all fine, no cratered primers, nothing other than a mystery with the numbers, especially since the first and last loads were so close, as well as the middle????

Questions
I started wondering if my digital scale had been subjected to RF interference during the loading session at my bench, and other sanity checks, as this is the first time I have seen this type of behavior with the Grendel. I was definitely scratching my head.

It could also be that my COL is so long, that I'm spiking the pressure from the start with the ogive jammed into the lands. Dimensional variation in the projectiles can account for different jump and jam depths, even with the same raw COLs, so I think I need to consider reducing the COL.

Experiences in the past with TAC and the 100gr NBT showed pressure signs right where one would expect them when I exceeded published velocities for max loads with that combination, to include blatant ejector extrusion, cratered primers, and velocity excursions from the safe trendline. Today, I didn't see one single instance of ejector extrusion or even a hint of ejector shadow on either of the load batches.

Conclusions
CFE is a very forgiving powder in my Grendel at 60 F with the above loads. I need to reevaluate my bench, look at COLs again, and double-up Chronographs next trip. I'm still at a loss on the 107gr SMK's. I suspect a mistake somewhere on my part. Either way, many of the velocities were above max book value for 24" Grendels, which is a major red flag I think, but I also suspect that CFE will safely deliver noticeably higher velocities than any of the other powders I have worked with, and not spike.

After posting this, another Grendel owner who broke ground with CFE223 testing said he also had unexplained and erratic speeds with the 100gr A-MAX, so we're thinking that this powder needs a certain degree of start pressure to burn consistently.

Even at ~ max listed book data of 31.1gr under the 123gr A-MAX, I'm within 11fps of an 18" Grendel. What this day did for me was establish a set of known parameters where I can look for accuracy nodes in the future with my set-up.

BTW, every one of these loads was shot at 500yds on a large rock formation, with nice impacts. We video'd it through a spotting scope when I shot on IPSC steel as well.

 

[polish handgunner]

I have been using 123 grain a maxes with AA2520.
In my 24" Les Baer 6.5 Grendel I get just under 2600 ft/sec.
Now I can't find 2520 so I may go with CFE223!

 

[LRRPF52]

I have been using 123 grain a maxes with AA2520.
In my 24" Les Baer 6.5 Grendel I get just under 2600 ft/sec.
Now I can't find 2520 so I may go with CFE223!

What are the details of your load?

Keep in mind that I used 2.272" - 2.277" COL. Bwild97, another Hide member, achieved the following with the 123gr Nosler Custom Competition and the 129gr SST:

24" J&T 6.5 Grendel

Nosler	NCC	123	2.250	CFE 223	31.00	WLR	2617 fps
Nosler	NCC	123	2.200	CFE 223	31.50	CCI 450	2681 fps
Nosler	NCC	123	2.200	CFE 223	31.70	CCI 450	2724 fps

Hornady	SST	129	2.270	CFE 223	29.80	CCI 450	2504 fps
Hornady	SST	129	2.265	CFE 223	30.50	CCI 450	2557 fps
Hornady	SST	129	2.270	CFE 223	30.80	Rem 6.5	2613 fps
Hornady	SST	129	2.270	CFE 223	30.80	CCI 450	2629 fps
Hornady	SST	129	2.270	CFE 223	31.00	CCI 450	2662 fps

 

[polish handgunner]

My 6.5 Grendel Handload

My Grendel handload consists of:
123 grain Hornady A max bullet
Papua case
CCI450 primer
30.65 grains of AA2520 powder
2.248 oal
This cartridge was fired in a 24" Les Baer barrel.

 

[LRRPF52]

Yes, AA2520 is one of the main powders AA used from the beginning. Seems to generate some of the best speeds with the 123gr and 129gr pills.

I just picked up an 8lb jug of CFE, as I'm really loving this powder, and I can use it for .223 loads as well.

Looking at the kernesl of CFE, I'm seeing 3 different grain types.

 

[svxwilson]

I have some 123 Amax and some 123sst I will load up with CFE here in the next few weeks. My Grendel is a bartlein 24". Are the sst and Amax similar enough to use the same powder table? Hodgdon doesn't list CFE for the Grendel but they do list it for the 6.5BR. I was looking at Hornadys loads for CFE thinking about starting my initial ladder at 29gr and work up to 31gr. And see what velocities I get from my 24" Grendel.

 

[LRRPF52]

That is a sound plan, starting with 29gr for starting load. The longer COL you use, the more case capacity you can get, with the pressure mitigated somewhat, until you touch the lands.

Figure out the COL for each of those in your chamber, because some of us have noticed that the 123gr SST loaded shorter. I just measured some factory Hornady cartridges with the 123gr SST, and they varied from 2.234", to 2.242".

The 123gr SST looks like it's a 123gr A-MAX with a cannelure, nothing more, at least on the outside. The have the same BC, and same boat tail length, so overall length side-by-side, so that would point to a nose profile of the same form. You just have to see where they start to engage the lands at with your chamber.

People have been killing lots of animals with them this season, including Alaskan Caribou. One was taken at 275yds, the other at 400yds with an 18" Grendel using the 123gr SST. The first bull he shot took a step and face-planted into the tundra.

6.5 Grendel Forum : : For the 6.5 Grendel Aficionado

 

[steve123]

Not to rain on your parade, and seriously not trying to be insulting or take away from your hard work but I've owned 2 Chrony's and used a friends Chrony that gave false numbers-up to 150 fps off, all three were off. Which gave myself and my friend fits because the numbers they'd give had no consistency from one outing to another.

It took buying a Oehler and doing experimentation with dope lining up to realize where the errors came from.

Never the less, using temp sensitive powders has it's own problems as well. Especially when summer comes around when a load was worked up in the cool of winter.

I had a 6mmART40 that I pushed the velocities on. I settled on H-4895 so I didn't have to hassle with velocity variations of more than 20fps. But because the load was hot other problems occurred. One was a occasional jamming issue which went away after reducing the load later on. The other was excessive pressure possibly loosening the barrel extension from the barrel, that's a theory though which others who have had a similar problem told me about. Also shorter brass life.

Another thing I've noticed is Lapua brass can handle a lot more pressure than other brands of brass which can be deceptive in showing pressure signs especially using CCI450 or Remington 7 1/2 primers.

BTW 2520 is the worst powder I've ever used for temp sensitivity. It's now relegated to low pressure plinking ammo in the 223 for USPSA paper stages. Does throw good though, just not best for long range stuff as a year around load.

 

[LRRPF52]

Not at all. I don't see it as a parade, just some data collection, so any critical input will be met with more welcome than non-critical. Yes, I'm aware of the Chrony's reputation. I have had good luck with mine for the most part. I've had it since 2007. If the lighting conditions are off, then it will error. It did show very consistent velocity increases over the 9-round pressure ladder, without any of those velocities dipping under the previous, and registering consistent speed increases per charge weight that has been expected with this particular barrel since 2009 with several other loads. That said, I would love to have an Oehler or a Magnetospeed.

Using the mv that it gave me for the factory 123gr Hornady A-MAX, I shot it out to 1200yds this summer in 80 F, at 4400ft ASL, and the dope was on. 14.4 mils was POA=POI, so that leads me to conclude that I was getting accurate velocity readings when the trajectory was on at 1200yds from a little 16" carbine.

Yes, the Lapua Grendel brass is a 60,000 psi case easy, but the AR15 barrel extension and Grendel bolt are not. After thinking about the higher pressure loads and a new bolt design, I have realized that a lower-pressure system has a lot of benefits to it, and you don't really see a huge performance increase by pushing this thing. Case capacity is what it is. I agree that looking at brass and primers for pressure is not the preferred method by any means, although I still do it with the understanding that it's mostly noise, but if I see cratering, then I know I'm in a bad place.

There are proof loads in the 67,000psi range that won't show any primer or brass deformation indicative of that pressure, which is why I look at the chrono. I have discussed Grendel pressure-testing with some of the engineers at Lapua, and they said they ran a bolt gun to 15% more pressure than a .300 Win Mag, using the 123gr Scenar. Velocity was 450fps faster than I can get in my .260 Rem safely with that bullet, and they finally made the brass useless, although I don't think the case failed. I doubt they would ever hold a primer again though.

If you would have told me that I was supersonic to 1318yds with the 16" Grendel, my response would have been to try to bring you back down to earth, so it really surprised me. Of course the elevation has a lot to do with that, but I still would be supersonic to 1050yds at sea level at even lower temp of 59 F. It isn't competitive with a .260 Remington for 1000yds, but my complete 16" Grendel with bipod, 2.5-10x44 PST, and magazine weighs less than my .260 Rem AR10 upper receiver group.

I haven't done any load development with AA2520, but being a ball powder, that doesn't surprise me. I'm still interested to see what CFE does now that it's winter, as you can have pressure spikes at lower temperatures as well if there is a nitroglycerine content. I'm going to run the same pressure ladder soon, since I have duplicate strings, so that will give me another set of data in this little blaster. Once I get some nice 40F or lower temps, I can do the same test again.

Thanks for your sanity check.

 

[steve123]

Okay, I just thought I'd mention those things that I had experienced.

I'm looking forward to seeing how well the CFE does as temps change. Keep us apprised please.

I was shooting my 15" AR the other day at 600Y with 75's which is always a eye opener compared to the bigger cartridges. I might try a 6.5G since I have a bunch of virgin brass for it.

A couple friends have 6.5G's. One has a 24" barrel and the other is a 18".. Seems like the 18" does just as well as the 24" at distance??? I'm thinking I'll try a 18".

Thanks for all the info!

 

[LRRPF52]

Hornady's 9th Edition lists a max load of 31.2gr of CFE at 2.245" COL, with 2500fps from the 18" AR15 they used in the 9th Edition.

31.1gr gave me 2489 fps with 2.275" in my 16", which is a bit fast, but not so fast as to rule out nuances of each barrel's own characteristics.

I have an 18" and another 16" on order through the Lilja group buy we did. I personally have no use for a longer barrel at this time because I do a lot of positional shooting in my DM Courses, where the terrain is such that you rarely have an opportunity to shoot from the prone.

High-quality, lightweight barrel profile, with high BC pills is the combination for success when shooting from positions for me, where support outside the human body is not available, leaving you with your sling and your training to make up the difference.