223 powder

[kxkid]

I have been on imrs load data site and it shows 3.2 of clays at 3700 cup and 3.1 of titegroup at 4000 cup. Has anyone used these powders in 223 and what does cup mean over paid?

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[kxkid]

Mean psi not paid

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[wildphilhickup]

cup means copper units of pressure.

[limitdown]

There's a formula to convert (approximately) btwn PSI and CUP.
PSI = -17902 + 1.51586 * CUP

Here's a scholarly-type article about it if you want to get technical.
www.shootingsoftware.com/ftp/psicuparticle2.pdf

Technically there's a "correlation" btwn the two, so it's not direct conversion. However, for simplicity, I use the formula for a direct conversion when calculation pressure for reloading.

[kxkid]

That gives me a negative psi for the loads I am asking about

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[Knight Diver]

In the article that derives the formula given here, he cautions that it is only valid for the pressures used in the derivation. He uses all typical rifle pressures. Your example here with Titegroup (a pistol powder) is not typical at all for 223 Rem and not included in his derivation. So the formula doesn't apply in your examples.

I have seen the load data for Titegroup in a 223, but it doesn't make sense to me. Way low pressure. Wrong "type" of powder for rifle.

I don't know why you would use that type of a load for 223. Can you tell me why you would want a very low pressure load like that for a rifle? I never understood why it was even listed in the load data books.

[kxkid]

Just wonder if it would work is all. And wondering if you can increase the charge over the Max that they say and be safe

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[happyfast79]

if your new to reloading there is no need to push the limits, dont try to go over max in an ar 15 type rifle as the bolt locking lugs are your weak link. if your needing to push your 223 that hard just upgrade to a magnum cartrige

[FlyFish]

There's a discussion of these loads here. Apparently they're subsonic loads intended for hunting small game in populated areas. I don't think I'd be in a big hurry to try them in any of my ARs (can they even cycle the action?), but maybe they have some use in a bolt gun - if you're careful to be sure the bullet actually exits the barrel each time.

As others have said - unless you really, really know what you're doing (the OP doesn't qualify, and after nearly 40 years of handloading I'm not sure I do either) never exceed a published maximum load.

[Jim243]

Kxkid

Are you looking for a AR pistol load or a sub-sonic rifle load?


Jim

[Sport45]

Originally Posted by kxkid

And wondering if you can increase the charge over the Max that they say and be safe

NO!!! Do not go over what Hodgdon deems maximum when playing with pistol powder in a rifle case. Pressures do not necessarily rise in a linear fasion with increased charge weights. A pressure spike could be dangerous, and going over 1000fps defeats the purpose of the reduced load anyway.

There are LOTS of powders that are suitable for rifle velocities in the .223 and I suggest you try one.

[kxkid]

Wow this just goes to show how people can't read. I am not trying to load these at all just curious. Several of u answered my questions and others no where near the subject.

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[Sport45]

Which of us can't read? You said you had been on IMR's (Hodgdon) website and found some loads for .223 using common fast pistol powders and asked if any of us had experience with them.

I have been on imrs load data site and it shows 3.2 of clays at 3700 cup and 3.1 of titegroup at 4000 cup. Has anyone used these powders in 223 and what does cup mean over paid?

You went on to ask if it was safe to exceed the maximum published loads.

Just wonder if it would work is all. And wondering if you can increase the charge over the Max that they say and be safe

This is a reloading forum so the natural assumption is that you are wanting to reload and are inquirig about using the Titegroup or Clays you have on the bench in your .223 Remington. For all we know, you already have a bunch loaded up and are just making a final sanity check.

I have quite a bit of experience using Titegroup in large rifle cases under cast bullets. They can be a lot of fun for kids and aren't bad accuracy-wise. But it is strictly a low velocity application.

Keep in mind that we can only see what you post. We really can't tell what you're thinking.

[Unclenick]

Kxkid,

I don't know if you read Bramwell's article, but he has subsequently pointed out his numbers are based on SAAMI MAP ratings, not actual measurements of particular rounds. He also points out his linear correlation is only valid for rifle cartridges running at about 30,000 psi and higher pressures. It does not apply to the pressure range you are interested in.

The copper crusher instrument (invented about 1860) was long believed to accurately reflect real peak pressure in a chamber, and its results were originally reported in psi because of this belief. Indeed, the U.S. military continued the practice of reporting copper crusher results in psi into the 1990's (long after we knew better), thereby causing considerable confusion about the comparability of military small arms ammunition pressures and their civilian counterparts. Misstatements about this continue unabated and all over the web today, as this article by board member FALPhil explains.

In the mean time, starting in the early 1920's, Piezo electric transducers were developed in several forms and that tended to give higher results than copper crushers did with higher chamber pressures, bringing the copper crusher results into question. In the 1960's, strain gauge instrument results were added into the mix and were found to support the Piezo device finding that copper crusher readings were below actual peak chamber pressures at the higher numbers, and that their output was non-linear (they become less responsive as pressure becomes greater above around 30,000 psi).

This presented the ammunition industry with a dilemma. Most pressure test barrels in use (you need a different one for each chambering) were copper crusher barrels, and nobody wanted to just throw those away. The military, which worries not only about maximum peak pressure but also about minimum pressure needed for fully automatic weapons, didn't want to revise all its procedures.

Also, just one SAAMI member ammunition manufacturer is responsible for each chambering's standards, including making and selling both reference loads and proof loads for that chambering to the rest of the industry. These folks control the peak pressure standard for the rounds they are responsible for. They would have to switch to the newer conformal Piezo transducers and fire the same reference loads in the same conditions in both kinds of pressure test equipment to see how the readings compare to come up with new standard numbers for the more modern method. A lot of work and new standards to publish.

The solution they came up with was to have two standards. As the maker responsible for a particular chambering got around to changing over to the newer test equipment, he'd run the above comparison, and from that data the new method maximum average pressure (MAP) standard would be established. But other makers might not yet have that equipment, so they could go on using the copper crusher MAP. But it was necessary to distinguish one standard from the other to prevent the wrong number being used in the test equipment. So SAAMI decided to start reporting copper crusher results in their own units, called copper units of pressure (cup), instead of psi, as had previously been done. The newer conformal Piezo transducer results would be reported as psi, which they more accurately reflect.

Thus, .308 Winchester may be loaded to 52,000 cup MAP or to 62,000 psi MAP by a SAAMI member ammunition maker, depending on which kind of test equipment he has. The two numbers represent the same test loads fired in the two different types of test equipment.