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RangerRick
05-09-2012, 09:17 PM
Chrono Report CFE 223 Powder, 20 inch barrel


SUMMARY

20 inch barrel, 1:8.5


Bullet: Swift Scircco 2, 130 grains
MV: 2400 fps
Powder: CFE 223, 31.5 grains
Primer: CCI 450
C.O.L: 2.265


Bullet: Swift Scircco 2, 130 grains
MV: 2400 fps
Powder: LeveRevolution, 30.6 grains
Primer: CCI 450
C.O.L: 2.265

Bullet: Hornady Amax, 123 grains
MV: 2513 fps
Powder: CFE 223, 32 grains
Primer: CCI 450
C.O.L.: 2.26

Bullet: Hornady Amax, 123 grains
MV: 2490 fps
Powder: AA 2520, 30.4 grains
Primer: CCI 450
C.O.L.: 2.26

Bullet: Hornady Amax, 123 grains, Factory load
MV: 2457 fps
Powder: Factory
Primer: ?
C.O.L.: 2.25

POWDER

CFE Stands for copper fouling eliminator. Supposedly this powder was developed for rapid fire miltary weapons. I guess when you have fired enough to be up to your arm pits in mini gun brass you can leave a lot of copper in a barrel (or six barrels).

This powder reportedly has an additive that forms a brittle alloy of copper that gets blown out of the barrel by the next round fired.

I haven't seen any data on temperature sensitivity, but since it's a ball powder it is probably more sensitive than the stick and short stick powders.

CFE 223 is denser than AA2520 but gives a little less muzzle velocity per grain than AA2520. So case capacity for equivalent muzzle velocities is about the same, maybe a tad better with CFE.


OBSERVATIONS

The CFE 223 powder has real potential in the Grendel, particularly with the heavier bullets. I need to do more testing, but lighter bullets look like they get a boost too.

Beware, I was working up the loads, so the string sizes are small. Now that I've homed in on some some safe loads, I can measure some larger sample sizes to get better averages

The best mv I have gotten out of my 20 inch barrel with Swift Scirocco 130 grain bullets before this was 2310 fps with 30.6 grains of LeveRevolution. Even that was pushing it because I was seeing slightly flat primers.

I got about 2400 fps with 130 grain Swift Scirocco bullets with 31.5 grains of CFE.

I think I can go higher with the CFE without excessive pressure, but probably not without compressing the load or exceeding the 2.265 mag length.

For the 123 AMax I got 2513 fps with 32 grains of CFE, 2450-2457 fps in Hornady factory loads, and 2490 fps with 30.4 grains of AA2520. There was more room in the case for CFE at 32 grains and no pressure signs, so I'm pretty sure I can go higher since I was using 31.5 grains with a 130 grain bullet. That will have to wait for the next round of testing, though.


BULLETS:

I tested 123 grain Hornady AMax, and 130 grain Swift Scirooco II's. All the bullets fed fine.

No issues with the AMax.

The 130 Scirocco's are long for the Grendel, like most bullets over 123 grains. In my rifle I had no problem loading them to mag length (2.265) and a little beyond without hitting the lands.

31.5 grains of CFE is about all I could get in the case without compressing.

The Scirocco's have an excellent reputation as a hunting bullet. They have very thick jackets (see pics) and good weight retention. The BC is listed as .571 which is hard to believe, the Berger 130 grain VLD is listed at .552, and the Nosler 130 Accubond is only .488.

Some people report that a BC of .571 with the Scirocco gets them spot on target at 600 yards with balistic tables.

I'm going to try some 129 grain Hornady SST's. They re shorter so I can get more powder in, but the BC is much lower, so I don't know if it buys you anything. Plus they don't have as good a reputation as the Scirocco's, but they cost half as much.

Here's the Scirocco:

http://i670.photobucket.com/albums/vv69/rfincher1/cfe%20223/SwiftSciroccoII.jpg

The Swift Sciroccco and 130 grain Nosler Accubond Side by side:

http://i670.photobucket.com/albums/vv69/rfincher1/cfe%20223/SwiftandNoslersidebyside.jpg

130 Grain Nosler Accubond:

http://i670.photobucket.com/albums/vv69/rfincher1/cfe%20223/NoslerAccubond.jpg


BALLISTICS

I ran a ballistics tables with the 130 Scirocco. I used a G1 BC of .550 with the Scirocco instead of the advertised .571, to be more realistic. They claim 1600 fps is the minimum expansion speed, but I've heard 1800 fps is more realistic.

You can see from the table you get 1800 fps to almost 450 yards. You get 1,000 foot pounds of energy out to about 400 yards and 500 foot pounds to about 925 yards.

http://i670.photobucket.com/albums/vv69/rfincher1/cfe%20223/SciroccoBalistics.jpg

I'll run a table for the AMax when I verify the max mv with CFE.


CONDITIONS:

Temp 76, humidity 56%, Sunny, light winds 2-4 mph at 2 o'clock from muzzle.

Chrono 15 feet from muzzle.


RIFLE:

Templar 6.5 Grendel, Alexander Arms chrome bolt, 20 inch Satern barrel 1:8.5 twist, WCI brake.

BRASS:

Lapua and Hornady. Both held about 36.4 grains of CFE 223 when filled to the brim of fired brass (not resized).

All brass had been fired at least once before, except the factory loads.

Hornady brass showed slight ejector marks in about 20% of the cases, even in factory loads.

Otherwise nothing remarkable about fired brass.


PRIMERS:

CCI 450, except Hornady factory loads, which have brass colored primers (Winchester?).


STRINGS FIRED:

One box of Factory Hornady 123 AMax cartridges, two 10 shot strings, as a control.

Several 10 shot strings of Hornady 123 AMax bullets, using 30.4 grains of AA2520, my usual hand loads.

130 grain Swift Scirocco II bullets with varrying loads of CFE 223.

123 AMax bullets with varying loads of CFE 223.


DATA

The Scirocco strings weren't long enough for useful stats. More to come later.

CFE 223 Hornady 123 grain Amax
32 grains

String: 7
Date: 5/7/2012
Time: 2:30:13 PM

Hi Vel: 2539
Low Vel: 2496
Ave Vel: 2513
Ext Spread: 43
Std Dev: 13

Velocity
2520
2501
2506
2510
2510
2510
2530
2515
2496
2539

Factory Hornady 123 grain Amax

String: 9
Date: 5/7/2012
Time: 2:47:22 PM

Hi Vel: 2487
Low Vel: 2450
Ave Vel: 2464
Ext Spread: 37
Std Dev: 11

Velocity
2464
2460
2478
2455
2487
2455
2473
2464
2450
2455


Factory Hornady 123 Grain AMax

String: 8
Date: 5/7/2012
Time: 2:42:56 PM
Grains: 130
Hi Vel: 2482
Low Vel: 2406
Ave Vel: 2457
Ext Spread: 76
Std Dev: 22

Velocity
2406
2460
2469
2455
2473
2482
2464
2437
2450
2478

RR

Drifter
05-09-2012, 09:41 PM
Great info that is very useful.

What was your perception of pressure and recoil between the CFE, LVR, and factory loads? How did the rifle function, and did the ejection pattern change significantly between loads?

Like anyone, I wish to maximize performance, but not at the expense of abusing the weapon (and shooter).

My questions are in the sense of a "feel" aspect, and not necessarily a measurable result. The Hornady factory load might serve as a basis for comparison that many people could relate to.

Any additional feedback would be appreciated.

ricsmall
05-09-2012, 09:44 PM
nice job RR. thanks for the data, ive been wondering about the CFE powder since I read an article about it. copper fouling after 200 rounds rapid fire in 5.56 was non existent in the test, so it sounds like good stuff.

RangerRick
05-09-2012, 10:35 PM
Great info that is very useful.

What was your perception of pressure and recoil between the CFE, LVR, and factory loads? How did the rifle function, and did the ejection pattern change significantly between loads?

Like anyone, I wish to maximize performance, but not at the expense of abusing the weapon (and shooter).

My questions are in the sense of a "feel" aspect, and not necessarily a measurable result. The Hornady factory load might serve as a basis for comparison that many people could relate to.

Any additional feedback would be appreciated.

I couldn't detect any difference in recoil between the Factory, CFE, and my AA 2520 loads with the 123 AMax. I use a WCI brake that's pretty effective so it damps the recoil anyway.

I put the scope on about 12X and could self spot without losing sight of the target at 100 yards. I didn't measure any groups, I was just working up loads at this point. Next step is to see what shoots well.

I tried LVR awhile back with the 123 AMax and couldn't get the same velocities as AA 2520, and it showed pressure signs. It was also dirty. It's just too slow for lighter bullets, I guess.

Factory, CFE, and AA 2520 AMax loads fed fine and the bolt locked back on empty. I have an adjustable gas block, so I have it set to be as gentle on the brass as possible while still locking back reliably.

The CFE burned pretty clean. Not as clean as the AA 2520, but close. If it keeps the copper fouling down, that would be nice. Both were MUCH cleaner than the LeveRevolution.

All the brass piled up at about 4 o'clock, about 3 feet away shooting off of a bench.

The powder is a fine ball so it meters well.

When shooting the 130 Scirocco the recoil is more, but not much. Maybe 10%? I open the scope up to about 10X to keep the target in sight at 100 yards.

The recoil seemed a lot less than the 130's with LVR even though the CFE gave me 90 fps more mv. I felt like the buffer may have been bottoming out with the LVR. I'm pretty sure it wasn't with the CFE. I guess it just has a longer impulse.

With the 130 Scirocco's and CFE all of the rounds fed fine. I started out at 29 grains and worked up to 31.5. Until I got to the 30 grain loads the bolt failed to lock back on empty. From 30.5 grains on up it locked back just fine.

The Scirocco loads I've shot before have all been very accurate (I hope so for over $50 a box of 100).

You can see from the picture ow thick the copper is. That should punch through a lot at that weight with its sectional density.

RR

RangerRick
05-09-2012, 10:48 PM
nice job RR. thanks for the data, ive been wondering about the CFE powder since I read an article about it. copper fouling after 200 rounds rapid fire in 5.56 was non existent in the test, so it sounds like good stuff.

What got my interest was one of the other guys on here posting about the great mv's he was getting with 130 grain bullets out of his 24 inch barrel.

I worked up a load with LeveRevolution awhile back for the 130 Scirocco that I was not really happy with. It shot OK but the energy wasn't as good as a 123 grain bullet.

This powder looks like a winner for 130 grain class bullets. I can't wait to try it out at longer ranges and see how it works.

I shoot some at a known distance range, where your fire one shot and they crank the target down, mark it and crank the target back up.

Under those circumstances you feed one round at a time. I may work up a load longer than mag length for that kind of shooting, if I can keep it off the lands and keep the pressure down.


RR

Variable
05-10-2012, 04:56 AM
Thanks Rick! Good info for future reference.:)

Shooter
05-10-2012, 05:38 PM
Thanks for posting, what i found abit strange is why i can get 2600 + fps with 32 gr cfe223 in my 20" satern barrel according to my chrony. My testing was about 55°. I guess it must be either chrony error or just different barrels produce different speeds but the difference seems pretty significant? Your average was 2513 mine is 90 or more fps just seems like too much for different barrels of same length, makes me wonder if my chrony is giving me good data

bwaites
05-10-2012, 06:20 PM
From another thread,

"I've run into the Chrony issue before. We each bought one box of 4 different factory ammo brands. We then sent 5 rounds to 3 other people with chronometers. We then shot the different ammo and came up with averages for the ammo, and then used that baseline to calibrate the differences.

Its not perfect, but it helps with different loads and ammos, and different rifles. We came to the conclusion that most chronometers are a bit optimistic, but not terribly so.

I'm going to try these loads, but I need to get some heavier bullets."

RangerRick
05-10-2012, 07:46 PM
Thanks for posting, what i found abit strange is why i can get 2600 + fps with 32 gr cfe223 in my 20" satern barrel according to my chrony. My testing was about 55°. I guess it must be either chrony error or just different barrels produce different speeds but the difference seems pretty significant? Your average was 2513 mine is 90 or more fps just seems like too much for different barrels of same length, makes me wonder if my chrony is giving me good data

Yes, my numbers were very different from Bwild (although he used a 24 inch barrel) and bwaites had a good comment about chronys.

I have a 20 inch Satern too, so I can't believe there is that much difference. If our chronys are measuring 3% different (me 1.5% low, you 1.5% high or some other combination like that) that would give us roughly the same numbers.

Have you measured factory Hornady 123 AMax loads? That might be a good rough calibration for all of us.

The Hornady box says they get 2580 fps with their Grendel 123 AMax loads. I presume that's with a 24 inch barrel, what the other conditions are I don't know.

I measured 2450 fps from one 10 round string, and 2457 for the other 10 round string from the same box with my 20 inch barrel in the ones I measured the other day with the CFE. 130-123 fps less is in the ballpark of what I would expect (100-120 fps difference between a 20 and 24 inch barrel) but a little low.

There again if I'm 1% low that would take it to 2475 and 2482 fps for the strings. Add 100 fps for the longer barrel and it's right on with the factory measurements.

I was shooting with the chrony 15 feet from the muzzle, 76 degrees, about 56% humidity, 300 feet above sea level.

My measurements track pretty closely with the Alexander Arms data for 19.5 inch barrels, but I don't know what their loads are: http://alexanderarms.com/images/pdfs/grendel_ballistics.pdf

One thing that makes me suspect I'm measuring low is that I shot at 600 yards last month with my hand loads zeroed at 300 yards. Both the Hornady and Ammo Guide ballistic calculators told me I'd have to come up 3.5 mils to be on the bull. I only had to come up 3.0.

If I increase my muzzle velocity in the calculators by 80 fps it's about right. I don't know if that means anything or not, but it tells me something is a little off somewhere.


RR

Variable
05-10-2012, 08:10 PM
Maybe we need a chrony comparison thread to figure where we all sit with ours? I've noticed my numbers seemed a little higher than some others with my chrony in the past (Shooting Chrony "Alpha Master")....

txgunner00
05-10-2012, 09:14 PM
Good report. Well done!

Comparing your 123 AMAX load my 8208 load, I'm getting nearly identical average velocities and extreme spreads but with 28.3 grains. How full is the case with 32 grains? Mine is just slightly compressed.

bwaites
05-10-2012, 09:30 PM
My CED M2 gives me an average of 2490 with Hornady AMAX factory loads from my Satern 20" with ambient temp of about 58 degrees.

I got 2720 from my 28" last summer, but ambient temp was in the high 80's. (Same lot of ammo, but not same box.)

Looks like I need to go run a few tests, but my 20" is off for some cosmetic adjustments.

RangerRick
05-10-2012, 10:06 PM
Good report. Well done!

Comparing your 123 AMAX load my 8208 load, I'm getting nearly identical average velocities and extreme spreads but with 28.3 grains. How full is the case with 32 grains? Mine is just slightly compressed.

Is that 28.3 grains of 8208 or CFE?

The level in the case with 32 grains of CFE was slightly higher than I get with 30.4 grains of AA 2520, so it was slightly compressed if at all.

bwaites was getting 2490 on Hornady factory 123 AMaxes at 58 degrees with the same barrel I have. I was getting 2450-2457 at 76 degrees.

I have a Competition Electronics Pro Chrono, btw. I got similar number to bwaits last year with the factory ammo, but temperature was in the 90's. Still, 20 degrees shouldn't make that much difference.

Maybe I need to put a new battery in the chrony and retest? Seems like everybody else is getting higher numbers.

From a relative standpoint I was getting 60+ fps better than the Hornady factory rounds, and somewhat better than my AA2520 loads.

RR

LRRPF52
05-10-2012, 10:09 PM
bwaites,

I can chrono your 20" with some factory ammo, then see how the same ammo reads with your chrono. This CFE is getting my attention now. If you run some moly-coated Berger 130gr VLD's with it, I wonder if you could get 2500fps, which is a great 800yd load.

ricsmall
05-10-2012, 10:16 PM
bwaites,

I can chrono your 20" with some factory ammo, then see how the same ammo reads with your chrono. This CFE is getting my attention now. If you run some moly-coated Berger 130gr VLD's with it, I wonder if you could get 2500fps, which is a great 800yd load.

that would be an interesting load. would an 8 3\4 twist be good for the 130 VLD?

bwaites
05-10-2012, 10:39 PM
bwaites,

I can chrono your 20" with some factory ammo, then see how the same ammo reads with your chrono. This CFE is getting my attention now. If you run some moly-coated Berger 130gr VLD's with it, I wonder if you could get 2500fps, which is a great 800yd load.



I'll see if I can find some 130's and try it. I was planning on that anyways.

bobke
05-10-2012, 11:49 PM
Don't have an immediate reference to same, but what is the manufacturer's stated velocity variance on chronos in question? +/- x percent? That might account for a portion of discrepancies.

biggdawg
05-11-2012, 12:40 AM
I have a CED M2 chrono and factory hornady A-Max 123 out of my 16" aa barrel average 2430fps at 70 degrees out.

Shooter
05-11-2012, 02:12 AM
I have only tested a few hornady factory loads out of my 20" satern barrel but i got 2477-2507 @ about 50° from chrony beta master. When i say a few thats pretty much it.

txgunner00
05-11-2012, 04:00 AM
Is that 28.3 grains of 8208 or CFE?

The level in the case with 32 grains of CFE was slightly higher than I get with 30.4 grains of AA 2520, so it was slightly compressed if at all.

bwaites was getting 2490 on Hornady factory 123 AMaxes at 58 degrees with the same barrel I have. I was getting 2450-2457 at 76 degrees.

I have a Competition Electronics Pro Chrono, btw. I got similar number to bwaits last year with the factory ammo, but temperature was in the 90's. Still, 20 degrees shouldn't make that much difference.

Maybe I need to put a new battery in the chrony and retest? Seems like everybody else is getting higher numbers.

From a relative standpoint I was getting 60+ fps better than the Hornady factory rounds, and somewhat better than my AA2520 loads.

RR

8208. 28.3 fills to just below the bottom of the neck.

Bwild97
05-11-2012, 06:51 PM
that would be an interesting load. would an 8 3\4 twist be good for the 130 VLD?

The 130g VLDs shoot very well out of my 24" 1-9 twist barrel to 300yds (ie) no keyholes. I have not put them out any farther than that.

ricsmall
05-11-2012, 08:49 PM
The 130g VLDs shoot very well out of my 24" 1-9 twist barrel to 300yds (ie) no keyholes. I have not put them out any farther than that.

thanks wild. they should be good in mine when I get it.

Drifter
05-12-2012, 01:00 AM
If I increase my muzzle velocity in the calculators by 80 fps it's about right. I don't know if that means anything or not, but it tells me something is a little off somewhere.



RR- I think your estimate for low speeds is probably accurate. Before the most recent lots of Hornady ammo hit the streets, I usually saw ~2515 fps from my 19.5" Satern. Additionally, I've started testing some Alliant Power Pro 2000 MR with 129gr SST's, and comparing my data to yours using CFE-223 with 130gr Swifts, and also BWild's data using both CFE-223 and PP-2000-MR with 130gr bullets. You also mentioned that your come-ups for distance shooting were less than what your velocities suggested. Taking everything into account, it seems to confirm that your readings are a little low. In the grand scheme, it doesn't matter much as long as your readings are consistent, and you're aware of the apparent discrepancy. In other words, no need to trash your chrono.

It appears that CFE-223 is providing better velocities than PP-2000-MR (or 2kMR as BWild's notes show). At the time that I purchased, both powders were seemingly untested in the Grendel, and I might have chosen the wrong one to play with. Data on snipershide.com indicated good temp stability with PP-2000-MR (even better than Varget IIRC), and speculation on CFE-223 is that it would be noticeably less stable (though I've seen no actual data, just hearsay comments via 'net searches). With everyone's collective testing, I'm sure we'll be able to draw our own conclusions in time.

Data shared by you and BWild is of substantial value, and I find myself referencing both threads quite a bit. Tremendous thanks to both of you for sharing the information.

RangerRick
05-12-2012, 05:05 AM
Thanks Drifter, like you say the relative speed is what's important. I'm getting 90 fps faster mv with the 130 Scirocco's so I'm very happy with that.

I need to shoot some larger strings to get a statistically valid sample, though.

I'm looking forward to trying them at 600 yards, or longer to see what their BC really is.

RR

Drifter
05-12-2012, 06:38 AM
The 130g VLDs shoot very well out of my 24" 1-9 twist barrel to 300yds (ie) no keyholes. I have not put them out any farther than that.

Berger recommends 1:9" twist or faster for the 130gr VLD, so most Grendel barrels will seemingly be on the edge of suitability with it (and many other heavier bullets).

1:8.75" to 9" has previously seemed appropriate for the Grendel. But with these new powders, kinda makes me wonder if consumer demand will eventually steer Grendel barrels to faster twist rates, such as 1:8", to better stabilize heavier bullets that can now be pushed at respectable speeds. Just thinking (typing) out loud...

Bwild97
05-12-2012, 10:02 PM
Maybe we need a chrony comparison thread to figure where we all sit with ours? I've noticed my numbers seemed a little higher than some others with my chrony in the past (Shooting Chrony "Alpha Master")....

I'm game!! should we decide on some parameters to keep the test as even as possible? Fresh battery, 15ft from muzzel, color the Projectile black with a sharpie to ensure a good read? I'm very flexible with ambient temps (50* - 80*f) but not with elevation, i'm pretty much stuck at 2000ft or higher. What are the chances of every one willing/able to test, getting a box of factory Hornady 123g A-Max ammo from the same lot? Maybe pick up a box of Wolf 120g MPT to test as well?

txgunner00
05-12-2012, 10:21 PM
I'm game!! should we decide on some parameters to keep the test as even as possible? Fresh battery, 15ft from muzzel, color the Projectile black with a sharpie to ensure a good read? I'm very flexible with ambient temps (50* - 80*f) but not with elevation, i'm pretty much stuck at 2000ft or higher. What are the chances of every one willing/able to test, getting a box of factory Hornady 123g A-Max ammo from the same lot? Maybe pick up a box of Wolf 120g MPT to test as well?

Maybe you could mail your chrony's to each other so you could compare the two in identical conditions.

Bwild97
05-12-2012, 10:47 PM
Maybe you could mail your chrony's to each other so you could compare the two in identical conditions.

I would be willing to try that too!

Variable
05-13-2012, 05:01 AM
I have a fair amount of Hornady from the first couple of lots. I'll have to see what my lot numbers are and post them. I also have a decent stash of Wolf MPTs from different years, but none from the last couple of years. I haven't restocked in a while.

When I get a chance I'll post the lots up and we can compare to see if anything matches up.

My altitude here is 1500 feet. I can go up or down some, but most spots I shoot are in roughly that neighborhood.

Variable
05-27-2012, 01:55 AM
Ok, my factory loaded Hornady 123 Amax lot numbers are:

3100602
3101177
3101635

I could only find one lot of Wolf 120 MPT represented, so either I burned all the other stuff up (I don't think so?), or it's all in cans I haven't got around to yet. It's all "0801" (meaning January of 2008). The secondary slips are all different two digit numbers, and I never have figured out what they actually mean.

LRRPF52
03-25-2013, 11:59 PM
I was shooting the 123gr A-MAX this weekend with 31.0gr of CFE from my little 16" carbine. It's an excellent hitter out to at least 600yds in 20mph full value winds. I didn't get a chance to run a ladder with it because the weather was so insane, I didn't even bother with setting up my chrono. My components are:

Lapua unfired brass
Remington 7 1/2 Bench Rest Primers
31.0gr CFE
123gr A-MAX
2.260" COL

Temperature was below freezing, like 17F I think, with terrible wind chill, and I did have very flattened primers on a few of the shots, but no cratering and no ejector channel extrusion.

I have a SAAMI Grendel chamber, M16 bolt carrier, H2 buffer, & JP adjustable gas block. The load felt stout to me, but not that much different from an AA factory 90gr TNT, so who knows.

I was able to group it at 100yds, with .5 MOA vertical, and 1 MOA horizontal, which was likely the wind gust. Once I get a clear day, I'll be able to see what this load can do for me, but it does great at hitting steel at 600yds in crazy wind.

stokesrj
03-26-2013, 12:53 AM
I've done a lot of chronograph comparisons and now understand how critical the set up is to the resulting readings. In short unless you shoot with the screens set up perfectly spaced, and perfectly square to the bore, and with the light angle exactly the same it is not uncommon to obtain readings +/- 15%. I am now using the magnetospeed chronograph with much more consistent results. But it also has it's limitations, it changes barrel harmonics, so accuracy nodes must be determined independent of chrono results. It also doesn't work with all firearms like the 1911 platform for instance. Also setup is critical, the bayonet must be alined perfectly parallel to the bore. But if you have those things under control, good loads that give 12 fps SD's with optical chronographs will give 4 fps SD's with the Magnetospeed.
Bob

LRRPF52
04-02-2013, 04:09 AM
I just looked at Hornady's 9th Edition data for CFE again, and they listed 31.2gr as a max load for the 123gr bullets, but 31.7gr for the 129gr IB, SST, & SP? They used Hornady brass for the tests. I wonder if the GMX limited the 123gr data, because they list data for weight classes that include several bullets, and the start pressure for the GMX is different than the A-MAX or SST in my experience.