Starting load?

[olddav]

Brace yourself I'm going to show my ignorance.

If I can not find load data for a bullet/powder combo for a given caliber is there a way to determine a starting point (minimum load).

version 2: Let's not focus on a load recipe for the Garand, think more in terms of general reloading. Say I have a .223 and I want to load it with VihaVuori N133 all the while using a 62 grain bullet. I know that VihaVouri N133 burns faster than H335 and slower than IMR 4227, without a recipe is it possible to determine a starting load for this combo?

[rocky.223]

what is your bullet, caliber, and powder you are planning on using. I like to go to the powder manufacturers website and try there first. The bullet manufacturer will also likely have load data as well. If you don't have one, a loading manual from a company like Lyman or Speer is an essential part of any reloaders kit.

[olddav]

What got me thinking was when I tried to find loading data regarding the M1 Garand. Not much out there as far as published receipts. My guess is there has to be some way to determine a starting point for a given powder in a given caliber with some limitations (burn rates and such).

[Misssissippi Dave]

One thing I have found useful. Old books and other out of print data is useful. It helps to know people that have been loading for many years. Often they have data that can help get you in the ballpark for different loads. It still helps to have more than one source going this route. Some powders do change over the years. Sometimes it is only the name of the powder that changes. You still should be able to find a starting point. Older people with many years of reloading under their belt are probably some of the most valueable reloading references around.

Most reloaders keep every reference source they have ever had as long as they think they may still want to do some reloading. Most reloaders also keep good records of loads they have used since they started loading. The internet has made it possible to access this information a lot easier than it once was. Like all things on the internet, don't believe everything you see, read or hear.

A search of the internet sometimes gets good results too.

http://www.loaddata.com/members/sear...etallicID=2713

http://web.archive.org/web/200006200...rpo/M1load.htm

[mehavey]

...when I tried to find loading data regarding the M1 Garand.
Not much out there as far as published recipes....

If you can't find it here for the Garand...
http://masterpostemple.bravepages.com/M1load.htm
...you're probably way OB in the load-combo boonies.




as for truly no-reference starting loads, the only way I know to comfortably find an entry point is
several "near" loads with like weight/shape/OAL bullets, and then gaming them w/ QuickLoad to find
best fit/narrow down the uncertainty.

The Garand, with its fairly circumscribed pressure/burn-rate limitations, is not one where you want to stray
too far from the published centroids.

[Lost Sheep]

An email to the powder manufacturer might yield some help.

Lost Sheep

[jwrowland77]

If you have a max but no starting point, I thought the general rule of thumb was to reduce max load by 10% and then work your way up.

Am I wrong in assuming this?

[jimkim]

Go look at Hornady #7. I think it has what you're looking for.

http://web.archive.org/web/200006200...rpo/M1load.htm

[Clark]

A 62 gr bullet in a 223 with a case 100% full of V133 will be ~ 45 kpsi.

That sounds close to the 55kpsi that the 223 Rem was registered at SAAMI in 1964.

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.

But the 1950 .222 Win case head used in the .223, can take 75kpsi all day with long brass life. That is a lot of wasted safety margin. More than 30%, when 3% suffices in the 270, 6mmRem, and 22-250. Of course, pressure is not the only issue when loading for AR15s, we want them to cycle nicely and throw the brass the right distance.

A 223 with 62gr bullet and a case half filled with V133 with have ~ 10kpsi.
That sounds low, but probably no stuck bullet with stick powder. Of course, pressure is not the only issue when loading for AR15s, we want them to cycle nicely and throw the brass the right distance.

[rg1]

In a Garand try the bullet and powder manufacturers web site or manuals and try to keep velocity in the 2600-2700 feet per second range with 150-168 grain bullet range. Using standard 30-06 load charts in the manual with appropriate speed Garand recommended powders this usually shows a 2-3 grain reduction from maximum 30-06 bolt action loads. You'll see bolt action loads in 30-06 using IMR4895 powder with maximums around 50 grains with 150 grain bullets while maximum recommended loads for Garands tops out at 48 grains with most people loading 46-47 grains of IMR 4895. You need to consult all the data manuals and compare them all. Vihtavuori has good info on-line. http://www.lapua.com/en/products/rel.../relodata/5/44
When in doubt about a particular weight bullet or powder most often you can safely use data for the next heavier bullet for starting charges for your lighter bullet. A chronograph is most useful tool when doing what you're proposing watching for expected velocities.

[Unclenick]

Olddav,

To answer your original question more directly, there is no simple rule of thumb you can use. To figure out what a powder will do requires knowing not only its burn rate but also its energy content per unit weight, how much is burned before it flips from progressive to digressive burning, and other factors. It takes a fairly sophisticated ballistic model to predict from that. The old Powley formulas still work, but are for a more limited number of conditions than you may find yourself looking at. Case fill limitations in particular.

Burn rate charts don't have much really useful information. They don't say whether two powders next to each other on the list are identical or are 10% different. What's worse, if you do a search on the web for burn rate charts and start comparing them, you'll discover no two agree completely with one another. The powder makers pay a lot for the testing and consider the exact results proprietary, so what you see in burn rate charts are all guesses about any powder the chart maker doesn't distribute. Thus, I'd trust a Hodgdon chart to be correct about the order of Hodgdon, IMR, and Winchester powders, which they distribute and control the burn rates of by specification, but not for them to have Accurate, Alliant, Norma, Ramshot, Scott, Somchem, or Vihtavuori or other powders necessarily in the correct order.

For example, I've found burn rate charts from different sources that ranked Bullseye's burn rate #1, #3, #5, #8, and #15. It all depended on what they tested it in.

I think a more useful type of burn rate chart is the type that puts several powder maker's products all on the same line to say they are all good for the same general range of applications. Here's one example from GS Custom Bullets in South Africa.

If you really want to try a powder not normally used in a cartridge, the QuickLOAD software is your best bet. Often you find the case fill would be poor (generally good not to go below around 70% fill in a rifle case if you can avoid it) or you sacrifice a lot of velocity or there's some other characteristic you won't like. But sometimes it does give you an unexpected clue that is useful.

For example, based on peak pressure, muzzle pressure and case fill, QuickLOAD suggested that Vihtavuori N135 was a good choice for 150 grain bullets in the M1 Garand. This was subsequently verified by experiment by myself and a couple of other Garand shooters. A load about 2.5% lighter than a standard IMR4895 load will produce the same peak pressure and barrel time, but fill the case 10% better, produce 12% lower gas port impulse, lower perceived recoil, and give up only about 35 fps out of 2700 fps to do this. This powder's downside is that it's expensive (about 25% more than the same performance quantity of IMR4895). But it burns cleanly, is accurate and comfortable to use.


OT,

I agree with Clark that the .223 is a wimped-out anomaly at SAAMI's end. The original spec was 52,000 CUP, but for some reason the same reference loads that produced that number only produced 55,000 psi in their Piezo transducer, so that's how it was set. When the CIP did the same thing on their equipment in Europe, they got 430MPa (62,366 psi) from the reference load, which is what they load to over there without problems. It's the same number they use for 5.56×45 NATO. (Don't be fooled by older military pressure data for this round which says 55,000 psi, but is actually 55,000 CUP; the military never adopted the Copper Unit of Pressure when SAAMI did in the 1960's. You just have to know which system a pressure was measured by, as the military reports both as "psi").

Note how all the other SAAMI cartridges that were originally rated at 52,000 CUP and later were retested and rated in a Piezo transducer got at least 60,000 psi. The .223 situation is some kind of bad instrumentation mojo.

[noylj]

Back when a powder companies products were similar and uniform, one could use data for the next faster powder by that company. If you didn't have a Herco load, you could start with Unique data. Likewise, the old IMR powders were easy to work this way.
Of course, the rule of using data for a heavier bullet still applies if you have data for your powder with the heavier bullet.
The only concerns are:
1) using a powder like 296/H110 that is so hard to ignite that only max loads are safe--otherwise, you can end up with a bullet and a wad of partially burned powder in the barrel and the gun won't like it if you fire another round.
2) If you were to go so low in charge weight that sufficient velocity could not be generated to get the bullet out the bore. I consider a minimum 550fps to be required to ensure that the bullet will exit.
You can not use data for just any fast powder, since they all have different combinations of manufacture (flake, extruded, spherical), levels of NG, suppressants and powder burn rate chemicals, and grain size/surface area.
The best solution is to call the US distributor or contact VV on the web and ask them for unreleased load data. All the powder companies I have contacted have been more than helpful.
It is also worth considering that if a given powder is NOT shown, there could be a very good safety or performance reason and you may want to re-think your powder choice.

[SL1]

Unclenick wrote:

Note how all the other SAAMI cartridges that were originally rated at 52,000 CUP and later were retested and rated in a Piezo transducer got at least 60,000 psi. The .223 situation is some kind of bad instrumentation mojo.

I agree that the .223 (as well as the .357 and .44 Magnums) were substantially down-rated in ACTUAL pressure and power when SAAMI adopted the Piezo transducer and psi standards.

But, I don't understand the ASSUMPTION that this was due to "some kind of bad instrumentation mojo." The folks on the standards committee who adopted those values are surely more or at least as qualified as we are to see that something is NOT making sense IF the intention was to produce the same ACTUAL pressures with both standards.

So, it seems to me that there is more to these "shifts" in performance between the two standards (CUP and psi).

It would be real helpful if the industry was more forthcoming about the REAL reasons for these performance shifts. Insisting that they ARE equal only damages their credibility, without convincing anybody. And saying that it is due to some sort of instrumentation anomally tends to damage their image of competence. Why can't they just deal with the anomally with better procedures and/or instrumentation so as to make a new standard that keeps the same level of actual performance?

SL1

[mehavey]

Take it from me. When you exceed 55K (per QuickLoad cals) w/ 223 by any substantive amount, you start opening up primer pockets to the point that 5-6 firings and you're done.

Not so much catastrophic failure and/or brass extrusion into ejector cutout on any particular shot-- the brass just can't handle the cumulative effects over multiple shots.

[SL1]

Case head expansion would seem like a good REASON to limit the cartridge max pressure.

However, that still seems to beg the question about why the CUP number is OK, while a psi number that would give the same case head expansion is not OK.

I don't think the SAAMI nor the NATO folks are worrying about how many reloads that guys like us can get out of the cases. Those guys are thinking only about the FIRST firing.

SL1

[Clark]

mehavey
Take it from me. When you exceed 55K (per QuickLoad cals) w/ 223 by any substantive amount, you start opening up primer pockets to the point that 5-6 firings and you're done.
Not so much catastrophic failure and/or brass extrusion into ejector cutout on any particular shot-- the brass just can't handle the cumulative effects over multiple shots.

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.
I did a study of different 223 dies for case length growth and concentricity over many firings and lots of pieces of brass. My standard test load was 66k psi Quickload, because that was all the powder that would fit. Brass went 25 firings and never got loose primers. Lengthwise case growth with FL sizing is faster with higher pressures.
When I work up to find changes in the extractor groove, which is a very sensitive pre cursor to primer pocket growth, the threshold in 223 is between 80k and 92 kpsi Quickload.
This is in contrast with 270 that is SAAMI registered at 65kpsi and I cannot get above 67kpsi with margins to stay away from primer pocket growth.
Again, the magnitude of the margin between SAAMI registration and case head capability is something like 3% in 270 and over 30% in .223.
The future may bring us commercial 223 +P and/or 223 +P+.
The future is not going to bring us any commercial 270 +P. Not with H06 tempered C26000 brass and large Boxer primer pockets in 270 and .409" extractor grooves.

[noylj]

Remember, all CUP does is "indicate" what the max pressure was.
Transducers tell you what the instantaneous pressure is and plots it over time. This gives you lots of information, and not just a crushed copper pellet.
This has also lead to the industry recognizing many powders that have pressure spikes too quick and sudden to show up in a crushed copper pellet but strong enough for them to be concerned. Thus, some powder have had their max charge weight reduced because they were having such random and large pressure variations near and at max charge.
I see it the old copper crush test was like filling up your car at the gas station, recording the milage, and driving until you run out of gas, re-filling the tank and calculating your MPG. I see the transducer as being like racing cars (see the Indy cars) that are fully instrumented and report everything that is happening at every moment as you drive. Totally different data sets and totally different data can be derived from it.
Finally, reloading manuals are only a guideline and if you think you know better, you can still free load whatever you want--just don't blame anyone else for the consequences.

[olddav]

lots to think about and with any luck understand.
Thanks for the info everyone.

[SL1]

It is easy to "muddy the waters" with some partial truths about how the peizo-electric measurements provide more and better data about pressure. And, it would not be surprising that some powders are no longer recommended because of "spikey" psi data.

What remains to be explained is why the psi STANDARD is clearly giving a lower actual pressure than the CUP standard IN ONLY A FEW PARTICULAR CARTRIDGES.

There is no arguing the point that the pressure is actually lower, because the charge weights and velocities are lower. If there actually are UNDETECTED pressure "events" in ALL CUP data for these cartridges, then our guns have been successfully enduring those loads AND THE ASSOCIATED PROOF LOADS for many decades, so it makes no sense to LOWER the standard to accommodate those.

In most cartridges, the psi standard was actually raised (numerically) compared to the CUP standard. That makes sense if you have discovered that that CUP numbers were actually low because they missed some spikes, and you can count on the piezo instruments to see those spikes and protect against any unusually high ones with the new data set for charge data going forward.

So, the question remains: why are the .223 Rem and the .357 and .44 Mags getting psi max pressures that fall "below the curve" in the graph of psi vs CUP SAAMI pressure standards?

SL1

[mehavey]

My standard test load was 66k psi Quickload, because that was all the
powder that would fit. Brass went 25 firings and never got loose primers

Interesting. My experience has been the opposite. In fact I once got wound up w/ 2495 substituted for 2520 and immediately blew out primers in the first two shots; expanded the primer pockets to where they looked like the bore of my 45ACP (); and extruded the most memorable ejector cutout imprints (actually a huge bas relief scultures worthy of Michaelangelo) I have ever seen.

Quickload calculated the after-action pressures at 77-78ksi, and I wrote a nice letter to Colt complementing them on their receiver strength. I would advise most shooters not to get within 10k of those pressures under any corcumstance.

As to 55+ and up eventually causing loose pockets in an entire case group (at least in Win brass), that's also my experience.

YMMV -- of course,

[Clark]

mehavey,
AR15s are not great for a wide range of loads; they are gas operated without adjustments, and they have extractor and ejector features in the bolt face.
Sometimes they seem to stretch brass on extraction.


Ruger #1s are different. They have breech faces with only a firing pin hole.
They will extract anything, and do it after the brass has cooled for a second.

Maybe that accounts for some of our differences.

[Unclenick]

That may be AR Specific.

A clarification: Modern Piezo transducer measuring equipment is available to let you see a plot of pressure over time with all the little details mentioned earlier. However, that is not the kind of equipment SAAMI specified for standard measurements originally. Their spec from 1992 standard equipment list include a peak detecting instrument and that only provides the peak value, and no graphical display. Those who have graphical displays have upgraded.


SL1,

My assumption about it being an instrumentation issue stems from my assumption that the number was arrived at the same way the CIP arrived at their higher number: they took a reference load used to calibrate copper crushers and put it in their Piezo transducer and used that result. If SAAMI did not use the old copper crusher reference load, then they did indeed lower the peak value. It's also possible that the SAAMI transducer uses a wider diameter, higher mass transducer piston. It's also possible the difference in sampling location affects it.

For an extremely lengthy but informative discussion that discusses methods and instrumentation errors at least briefly, but from the perspective of experienced persons in the field, read this thread at the 24 Hour Campfire. If you aren't wanting to take the time to go through the whole thing, just read the posts by Denton Bramwell, Hartmut Broemel, and Ken Oehler. They are not in full agreement and some sacred cows get taken to the alter. Fascinating business.

[Unclenick]

Apropos of this thread, I just noticed on the CMP forum mention of primer pockets shooting loose early and even case heads separating on more recent production .223 from Winchester. Remington complaints, too. One comment that Winchester was great in the early 2000's (I have a good bit of that brass and have had no issues associated with it). So, maybe the commercial makers have lightened the stuff recently to adapt it to the SAAMI spec. Not a good thing for AR shooters.