Question about loading .223 Rem "hot."

[wncchester]

"if we are carefully using our chronographs and our QuickLOAD programs, we SHOULD have reasonably educated estimates of what our pressures are running."

Yeah, we should. And you've gotten some well thought estimates/guessimates now. But, in most scientific circles all those estimates would be called WAGS (Wild-Azz Guesses) and they can't be otherwise.

Thing is, we all know ballistics isn't a straight line science, so I wonder how accurate the guesses are and how all that is going to help you if it is. Rifles aren't "average" devices, they are individuals, so even if the guesses are correct on average, the average rifle differers widely from average so average numbers are largely irrelivant to individual shooters. And that's not a guess.

I know a smart man who bought a new M70 in .22-250 a few years ago. He made his first reloads with mid-range Hodgdon book charges of Varget. Accuracy was very good but ... EVERY virgin primer pocket (R-P) expanded so much the cups fell out when he opened the bolt, you want to guesstimate what pressure that "modest" charge was producing? And does it matter? Or maybe he should forget guessing pressure and just develop his next loads to match what he gets in that rifle with his cases and his bullets and his powder lot? (That's what he's done. Like I said, he is smart, that was just his very first experience in reloading.)

[mehavey]

...smart man who bought a new M70 in .22-250 a few years ago. He made his first reloads with mid-range Hodgdon book charges of Varget. Accuracy was very good but ... EVERY virgin primer pocket (R-P) expanded so much the cups fell out...

My first reaction is that wncchester is eactly right... it's an estimating game. And the first step/shot is the most tenuous.

My second reaction would be that the (a?) Chrono might have (would have) told him he was operating out of the pressure range the manuals were giving him immediately.

My third reaction is never start near the top (which smart man was careful to observe) for that very reason.

My final reaction is that I got my Oehler-35 seven years ago after 36 years of reloading. How I stayed alive so long without it remains the second great mystery of my life.
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My final final reaction is that what ocurred to smart man was very unusual. Did he take the remaining loads apart to check powder appearance against that still in the Varget can? ...Charge weights against the book? ... Re-weigh the bullets themselves (against the off chance he'd grabbed a different projo than the book)? ...Slug the barrel (or have a gunsmith do it)? Check gun headspace against that of the FL-sized/reloaded cartridge (off chance that headspace was way outta limits)? ...Call Hodgdon?

I don't like mysteries in reloading (other than as mentioned above -- and that's history now). It puts me off my feed.

[Unclenick]

QuickLOAD's model was developed pressure matching CIP test barrel readings, and since the CIP uses 62,366 psi (4300 bar), once you get QuickLOAD tweaked to match your gun's performance with a particular bullet and powder, you can use that number in the program as a limit. My assumption is that SAAMI test barrels will just show a lower number from the same rounds. I've certainly had no issues firing Euro-origin 5.56 in my AR or in my Dad's Remington 788.

The 77 grian SMK is stubby (.994" long) for its weight and should be stablized by a 9" twist at standard metro conditions according to the calculator on the JBM site, giving a gyroscopic stability factor, s, of 1.4. If it is to be fired at much below freezing, stability will be less than stellar in the 9" barrel. You'd have to know ahead if that's a problem?

Proof pressure minimum is 71,500 psi and maximum is 77,000 psi for .223. Contrary to some rumors (and I got this directly from SAAMI technical director Ken Green over the phone) proof rounds are loaded with standard commercial brass which, though it may come through the experience unreloadable, does not fail.

Damaging a bolt action rifle appears to take a good deal more pressure than proof loads, as Clark can likely tell you. Even Hatcher's Notebook shows numbers over 100,000 psi (and Hatcher judged pressure by copper crushers that read high pressures lower than they actually are). Hatcher did have to get some extra hard case heads made for some of his high pressure experiments because brass would let go before the gun suffered those symptoms. (I don't recall if that was because he was using the '03 action, which exposes a short unsupported portion of the case head, or if it included his Garand tests?)

Also note that you can handload with smaller variance than commercial ammo makers do. If you've pulled much commercial ammo you'll know the charge weight distributions can be substantial. The SAAMI pressure specs are maximum averages and they assume a fairly generous standard deviation to allow for that. The example I see is on Fr. Frogs site for .308, and you can get some idea of how tight they expect the pressure to be held from that:



There's a fair amount of wiggle room. Also, as I mentioned earlier, the .223 is smaller than a .308, so if you put it in an action designed for .308 and fire it at .308 pressures, the bolt thrust is only 64% of what the .308 produces at those pressures.

With the 77 grain SMK you only need 2649 fps to make 1200 ft-lb. That's just not hard to get to. Hodgdon says BL-(C)2 can put you over the 2800 fps mark with it (Winchester case, 24" tube). QuickLOAD says that load would run 53,518 psi, incidentally. That might be an interesting combination to work up with using the Pressure Trace?

BTW, does your state require 1200 ft-lb measured performance, or just ammunition that is rated at 1200 ft-lb? The commercial ammo is all rated with 24" test barrels.

Originally Posted by Wncchester

EVERY virgin primer pocket (R-P) expanded so much the cups fell out when he opened the bolt, you want to guesstimate what pressure that "modest" charge was producing?

Sure. If you have the barrel length and measured velocity and the bullet and powder charge information, there is a relatively straightforward relationship between the two. Your smart friend's velocities should have been above the given ones. He provides us with yet another example of why you start with starting loads and not in the middle range, as many seem to want to do? You undoubtedly will get away with it most of the time, but it can cost you, at least in brass, on the occasions where that doesn't fly.

It is kind of unusual to get good accuracy from a warm load, which makes me suspect he got a lot of Remington foreign contract brass. I understand they've had some trouble with some of it being too soft? Even if true, it's no excuse for not starting at the bottom, but rather is just another reason why you should.

Not too long ago a fellow on the forum used a Speer manual .243 load in a Handy rifle. It kept popping the action open on firing, and he hadn't got up to the maximum yet. His velocities were well above the manual velocities. From that, it was possible to work out that he was firing at proof pressures.

A rule of thumb:

Take measured Velocity divided by manual velocity (for same barrel length) and cube the result. Multiply that cube by the manual pressure. This is just ballpark, as it doesn't account for change in ballistic efficiency with pressure, but gives you some idea, assuming the manual's listed pressures were valid.

You can also work the load in QuickLOAD by altering case volume until the measured velocity is achieved. That does take ballistic efficiency into account.

[Unclenick]

SL1,

Just out of curiosity, I took a look at Federal Premium's site. They don't list any .223 ammo under 1223 ft-lb (this will be a 24" tube, again), if that rating is what matters to the State? Their 60 grain Nosler Partition load shows 1330 ft-lb from that same tube. If I put that bullet together in QuickLOAD using BL-(C)2 to run 1330 ft-lb (3160 fps) out of 24", I have to shorten the barrel to 19.3" to drop it to 1200 ft-lb (3000 fps). So that load or your own version of it would be a pretty safe bet for 20" barrels and up.

[Clark]

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

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Purpose: To develop a method of finding handloads that optimize performance but still have long brass life.
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My test data:

223 Hodgdon website: 223 Rem, H335, 25.3 GR. 55 GR. SPR SP, 2.200", 24"
barrel, 3203 fps, 49,300 CUP

Test: Ruger #1, CCI 400 small rifle primers, LC brass once fired
processed from Scharch and prepped by me, 55 gr Vmax moly, H335

pic left to right: unfired, 28, 29, 30, and 31 gr.

unfired, extractor groove .329"
28 gr, extractor groove .329", 11% overload 69 kpsi Quickload prediction
29 gr, extractor groove .329", 15% overload 80kpsi Quickload prediction
30 gr, extractor groove .3295", 19% overload 92kpsi Quickload prediction
31 gr, extractor groove .3320", 23% overload 106kpsi Quickload prediction

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308 Hodgdon max book load:
308 WINCHESTER, CASE: WINCHESTER, BBL: 24", PR: FEDERAL 210M, 168 GR. SIE HPBT COL: 2.800" H335, 42.0 gr., 2631 fps, 49,300 CUP

My test:
Pacific .308 Win reamer, VZ24 trued action, A&B fluted stainless 24" F54 barrel, H335, CCI200 primer, 2.9" OAL, Speer 168 gr. HPBT Gold Match, brass: Win308Win:

0) 42 gr. QL= 2565 fps & 46 kpsi, 0% overload, did not load 42 gr.
1) 43 gr. QL= 2618 fps & 49 kpsi, 2% overload, ok
2) 44 gr. QL= 2670 fps & 52 kpsi, 5% overload, cratered primer this and higher
3) 45 gr. QL= 2722 fps & 56 kpsi, 7% overload
4) 46 gr. QL= 2774 fps & 60 kpsi, 10% overload
5) 47 gr. QL= 2825 fps & 64 kpsi, 12% overload
6) 48 gr. QL= 2875 fps & 68 kpsi, 14% overload, mark on brass from bolt face extractor this and higher,
7) 49 gr. QL= 2925 fps & 73 kpsi, 17% overload
8) 50 gr. QL= 2974 fps & 78 kpsi, 19% overload, extractor cut on brass expands .0020"
9) 51 gr. QL= 3024 fps & 84 kpsi, 21% overload, extractor cut on brass expands .0020"
10) 52 gr. QL= 3073 fps & 90 kpsi, 24% overload, extractor cut on brass expands .0110", primer fell out,

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243 1903 Turkish Mauser, 24" A&B F54 moly chrome barrel 243 short chambered large ring, cut threads for small ring. standard 243 reamer,

Hodgdon data 36.5 gr 2.65", they claim is 50,400 c.u.p, while Quickload predicts 47, 816 psi

42 gr Varget .912" length 87 gr bullets, 2.6" OAL, .405" extractor groove
Quickload predicts 66 kpsi
no egg (extractor groove growth)
spent primer hard to de cap

re used same Speer case
43 gr Varget, .912" length 87 gr bullets, 2.58" OAL, .405" extractor groove
Quickload predicts 72 kpsi
no egg (extractor groove growth)
spent primer hard to de cap

re used same Speer case
44 gr Varget, .912" length 87 gr bullets 2.595" OAL, .405" extractor groove
Quickload predicts 77 kpsi
.001"egg (extractor groove growth)
spent primer easy to de cap
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My conclusions:

1) The 1889 Mauser 7.65x53mm case head design, when built with a large Boxer primer and shot in a strong rifle is good for 62kpsi factory ammo and 65kpsi custom hand loads.
Pressure sign: primers fall out
Better pressure sign: primer insertion is too easy
Best pressure sign: extractor groove grows .001" anywhere around the circumference.
Examples: 22-250, 243, 6mm Rem, 250 Savage, 257 Roberts, 25-06, 260 Rem, 6.5x55 [US brass], 270, 7mm-08, 7x57mm, 280, 300Sav, 308, 7.62x51mm, 30-06, 8x57mm, 338F, 358, and 35W.
Expect extractor groove to grow in in one shot with 75kpsi Quickload prediction.

2) The 1950 designed .222 case head with small rifle primer is good for 75 kpsi with custom handloads.
Pressure sign: primers fall out
Better pressure sign: primer insertion is too easy
Best pressure sign: extractor groove grows .001" anywhere around the circumference.
Examples: 17 Rem, 204 Ruger, 221 Rem Fireball, .222 Rem, .223 Rem, 5.56x45mm, .222 Rem mag, 6x45mm.
Expect extractor groove to grow in one shot with 86kpsi Quickload prediction

3) The 1889 Mauser 7.65x53mm case head design, when built with a small Boxer primer and shot in a strong rifle with bushed firing pin hole is good for 85kpsi custom hand loads.
Pressure sign: primer pierces
Better pressure sign: extreme cratering of primer
Examples: 22BR, 6mmBR, 6x47mm, 6.5x47mm, 7mmBR, 30BR, Lapua small primer 308
1907 Sav99 with non magnum primer and with non bushed large firing pin pierces at ~ 65 kpsi Quickload prediction

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an old post somewhere else, no longer available, in response to a request from me, from an engineer that calculated the case head strengths using von mises formulas:

ASS_CLOWN
one of us
Posted 22 June 2004 07:43
Clark,
Here are the results of the von Mises stress calculations for the 223 Remington case head.
Using mechanical properties for C26000 brass (cartridge brass)
Temper - H06
Tensile yield strength - 65,300 psi
von Mises stress at the Primer pocket surface - 117,186 psi
von Mises stress at the Extractor OD - 65,300 psi (initiation of yielding)
Chamber pressure - 86,427 psi (Nominal properties)
Chamber pressure - 80,809 psi (minimum properties)
Chamber pressure - 92,044 psi (maximum properties)
Again these values are ONLY valid for a H06 tempered C26000 case.
ASS_CLOWN
PS
The Mauser case head nominal condition chamber pressure for the initiation of case head yielding with H06 C26000 brass is: 76,977 psi
The H&H magnum case head nominal condition chamber pressure for the initiation of case head yielding with H06 C26000 brass is: 79,597 psi
The Rem Utra magnum case head nominal condition chamber pressure for the initiation of case head yielding with H06 C26000 brass is: 83,950 psi
The H&H magnum case head nominal condition chamber pressure for the initiation of case head yielding with H06 C26000 brass is: 79,597 psi
The 460 Weatherby magnum case head nominal condition chamber pressure for the initiation of case head yielding with H06 C26000 brass is: 89,987 psi
The Rigby case head nominal condition chamber pressure for the initiation of case head yielding with H06 C26000 brass is: 90,450 psi
The 7.62X39 Soviet case head nominal condition chamber pressure for the initiation of case head yielding with H06 C26000 brass AND LARGE RIFLE PRIMER is: 66,769 psi
The 7.62X39 Soviet case head nominal condition chamber pressure for the initiation of case head yielding with H06 C26000 brass AND SMALL RIFLE PRIMER is: 81,609 psi
The geometric and mechanical property tolerances for the C26000 H06 material and "estimated" case tolerancing provide for a +/- 7% value from the nominals I posted above.

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What does is all mean?
I find the .223 gives up the ghost at 86 kpsi +/- 7.5% QL
I find that the 308/243 gives up the ghost at 75 kpsi +/- 3.5% QL
AC predicts .223 gives up the ghost at 86.4 kpsi +/- 7%
AC predicts 308/243 gives up the ghost at 77 kpsi +/- 7%
Pretty good correlation between that engineer's calculations and Quickoad predictions of my tests, huh?

[Unclenick]

QL says 92,000 PSI where you measure surpassing the yield, and he says 92,004 PSI maximum. A little hard to get much closer than that. Good deal, and should give SL1 lots of assurance.

And I'll add that I've found Scharch to be good people to deal with for new brass. Glad to hear their once-fired is satisfactory, too.

[mehavey]

In case anyone was wondering, this has turned into a very

A. Educational thread
B. QuickLoad confidence-building thread
C. Scary thread

A. [ ]
B. [ ]
C. [ ]
A&B [ ]
A&C [ ]
B&C [ ]
All of the above [X]

That said [actually Unclenick said]....

- Take measured Velocity divided by manual velocity (for same barrel length) and cube the result. Multiply that cube by the manual pressure.....
- You can also work the load in QuickLOAD by altering case volume....

I've also just kept adding virtual powder until the errant velocity was reached and looked at the [new] pressure produced. As this also plays into the relative case-volume/ballistic efficiency effect, what is the Peanut Gallery's opinion on indication of true chamber pressure conditions?

[SL1]

to all the folks who contributed to the answers to my question. I can't think of anywhere else that I can get that type of information.

Is this a great forum or what?!

SL1

[mehavey]

But after all that thrashing, smashing and bashing.... did we help you decide ????

[SL1]

The information provided has definitely helped me better understand what to expect in .223/5.56 brass. I had become a little concerned by finding some once-fired military brass that seemed to have experienced significant expansion, as well as some posts that seemed to indicate that head expansion and short case life were common for the .233 Remington cartridge.

I think I can go with the 22" barrel and 1-in-9" twist and get a rifle that I can load from about 100 to 1200 ft-lb level with suitable POTENTIAL accuracy, plenty of safety margin, and reasonable brass life at the top end.

I'm still trying to work out the weight I want and what components will provide that. But, that is another thread.

SL1