Loading .223 for 5.56 gun

[Whiterabbit]

So I'm looking to make another batch of ammo and considering a time saver, given I have to borrow a rifle to test it.

Here's the deal. The online balistics calculator I found stated basically for all factors I have constant, the faster my planned bullet flies, the better. The ONLY intended rifle for use will be a bushmaster ar-15 I'm told was designed to handle 5.56 pressures just fine.

So I have my loading data that states max load which I WILL NOT exceed. But I know that .223 is not supposed to achieve the same pressures that 5.56 can, right? So that begs the following question:

For this bullet, for this planned cartridge, for this rifle, can I just skip straight to max recommended load? max +0 -.2 grains of powder for the charge, and make a bunch? Or is this a safety concern anyways?

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And on a related question, does everything also apply directly for a .45 colt round in a 454 casull chamber? Straight to max load without concern?

[donger]

You are correct about 223 vs 5.56 pressures but always start on the lower end when working up loads.

[GeoffLinder]

DO NOT EVER just duplicate a max load recipe!

As always START 5% below any charge weight listed as max (or what anyone says is OK to use just because they use that charge weight) and work it back up in YOUR rifle to the velocity you want. If pressure sign is found then back it off a little and stop there for that powder in that rifle.

Remember, you will almost always be loading .223 brass anyway unless you get your hands on once fired military cases, there really is almost no difference in the brass. 5.56 and .223 differences are mostly about the throat of the barrel and where the rifling starts.

Most AR's are chambered in 5.56 to prevent surplus AP and tracer ammo from causing over-pressure if the bullet tip hits the rifling when chambered. A .223 chambering can cause over-pressure IF 5.56 military ammo is used where the bullet touches the lands before firing. Otherwise .223 and 5.56 are pretty much interchangeable ammo-wise.

[XDRoX]

It's never safe to start at max loads. Better to take it slow.

You could always load light to heavy, 10 rounds of each. And try them at the range. When you see signs of pressure, just stop.

[Whiterabbit]

I'm interested in data, not rhetoric (there's already plenty of threads with the dogma and rhetoric to explain the qualitative safety requirements when participating in a dangerous hobby.)

So in the spirit of quantitative discussion, let me ask the same question again using numbers in the hopes of having real information addressed with real information.

The internet tells me max SAAMI pressure for the 45 long colt is 14000 PSI, and that some handguns are capable of holding 28,000 PSI from a 45LC. The 454 casull is 65,000 PSI.

So the theory is that if I buy a firearm chambered in 454 casull, the chamber can take 65ksi pressure, period. It has to. But the rhetoric from posts above and many threads here state that, even in this case, 14ksi using 45LC brass is absolutely unacceptable and very dangerous, even though select (ruger) 45LC firearms can take 28ksi rounds, and every single 454 firearm absolutely must be able to handle pressures far higher.

SO: if I absolutely can not in this case even consider starting at SAAMI pressure spec for 45LC in this case, why not? I've established that it is not a brass issue or a chamber issue. So what obvious safety oversight am I making? And if there is more than one, I'd be most interested in a comprehensive list.

In this case (45LC), since it is easier to talk actual data, not just qualitative emotional statements. Conclusions can absolutely be extrapolated over other cartridges.

[GeoffLinder]

Mutters under breath while typing "Methinkin' we've got ourselves anutha' freakin' pressure number troll here, eh?"

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To the OP: How would you even go about measuring the pressure you get in your firearm to compare that with your interpretation of published pressure data taken from mfgr. test barrels? It is an established fact that muzzle velocity and chamber pressure are not necessarily correlatable and that one cartridge does not perform the same as another (read linear comparison).

Pressure measurement is done by ammo mfgr's in a manner that really doesn't relate very solidly with what you will get with reloaded rounds in any specific firearm. There are way too many variables to take into consideration to say a specific pressure will be developed by ANY specific recipe. A specific recipe may flow primers in one rifle and not in another.

There are way too many things wrong with your thinking here for me to go any further than I have in trying to set you straight. The internet tells many people many things, in this case it is telling you more than you are willing to understand.

BYW, I strongly advise your friend to not loan you his rifle for testing your Google derived reloading "theories"

[Whiterabbit]

OK, I don't mind the concept of variable pressure numbers as reason enough to ignore the concept of pressure entirely, but could the pressure really be off (in this case) by a factor of FOUR? I'd think that if the good calguns folks start to fret about stopping bullets in barrels at as little as 10% under max load, that the pressures generated at the top of saami specs would be a percentage above max, not many times over?

Do we have to be considered as counting the pressure as to simply be concerned with a digital condition? ("safe" vs"unsafe"?)

[SixPointEight]

Mutters under breath while typing "Methinkin' we've got ourselves anutha' freakin' pressure number troll here, eh?"

-------------------------------------------------------------------------

To the OP: How would you even go about measuring the pressure you get in your firearm to compare that with your interpretation of published pressure data taken from mfgr. test barrels? It is an established fact that muzzle velocity and chamber pressure are not necessarily correlatable and that one cartridge does not perform the same as another (read linear comparison).

Pressure measurement is done by ammo mfgr's in a manner that really doesn't relate very solidly with what you will get with reloaded rounds in any specific firearm. There are way too many variables to take into consideration to say a specific pressure will be developed by ANY specific recipe. A specific recipe may flow primers in one rifle and not in another.

There are way too many things wrong with your thinking here for me to go any further than I have in trying to set you straight. The internet tells many people many things, in this case it is telling you more than you are willing to understand.

BYW, I strongly advise your friend to not loan you his rifle for testing your Google derived reloading "theories"

This. Never think, oh this is the given pressure for this round, and max load is given as X, I'll be fine. Way too many things affect pressure to just call it like that. A round that produces X pressure in one rifle will produce Y pressure in a different rifle, with a different size chamber, different throat length and wear etc.

And don't think that just because the rifles are the same make and model, they are the same. Hell even if they are CONSECUTIVELY produced rifles they probably aren't the same. There's tolerances in production lines, and these tolerances could have an effect on the pressure of the round.

With that said, if you still think you're smarter than every other reloader, and the people who research/write the manuals. AND you feel safe doing it, then in the end it's your choice. Just stand far away from where your shrapnel may injur other loaders.

My opinion, if you must load for a firearm you don't have on have, load at or just a hair above book minimum. For a firearm you're just punching paper with, it will be fine. If you're hunting, you'll want to work up to high velocities, and if you're shooting a competition, you'll also want to work up.

[SixPointEight]

OK, I don't mind the concept of variable pressure numbers as reason enough to ignore the concept of pressure entirely, but could the pressure really be off (in this case) by a factor of FOUR? I'd think that if the good calguns folks start to fret about stopping bullets in barrels at as little as 10% under max load, that the pressures generated at the top of saami specs would be a percentage above max, not many times over?

Do we have to be considered as counting the pressure as to simply be concerned with a digital condition? ("safe" vs"unsafe"?)

You're using an example where the difference is 4x.
223 max pressure is in the realm of 55,000 psi.
556 max pressure is in the realm of 62,000 psi.
That's only about 10% difference. While not likely, it could cause a problem. Let me put it to you in a real world example.

Working up a load with varget in my 5.56 rifle I couldn't get enough powder in the case to have pressure problems.

Working up a load with AA2230 in my 5.56 rifle I started getting flat primers .8gr below max load. The data listed was .223 data. So by your logic, I should have kept working up in powder loads because it SHOULD be safe.

[Whiterabbit]

By the way, it occurs to me that this thread is heading in a direction that could get out of hand very quickly. Please understand that I am interested in an intellectual, rational, and theoretical conversation. The goal is to discuss information that can be used to make decisions, not discuss decisions and then the reasons to do so.

My goal is good spirited discussion, not "trolling" or "personal attacks" or any sort of emotionally charged discussions.

Thanks!

[Whiterabbit]

You're using an example where the difference is 4x.
223 max pressure is in the realm of 55,000 psi.
556 max pressure is in the realm of 62,000 psi.
That's only about 10% difference. While not likely, it could cause a problem. Let me put it to you in a real world example.

Working up a load with varget in my 5.56 rifle I couldn't get enough powder in the case to have pressure problems.

Working up a load with AA2230 in my 5.56 rifle I started getting flat primers .8gr below max load. The data listed was .223 data. So by your logic, I should have kept working up in powder loads because it SHOULD be safe.

Good data. Noone's logic states someone should continue past an unsafe condition. But my logic did state you SHOULD have been fine at max load. This is exactly the kind of data I'm interested in.

I'd love to hear additional information about this example/your experience in particular while I've got you in the thread. Were you able to really see that it was caused by pressure? If it wasn't pressure, would you consider that (a non pressure issue that could lead to a flat primer) a safety issue?

[GeoffLinder]

But my logic did state you SHOULD have been fine at max load. This is exactly the kind of data I'm interested in.

That's exactly the problem, a max listed load may be safe in most everything, BUT, a batch of bullets one half ten thousandth larger than what was tested to set that max load, a shorter OAL, a smaller internal volume case, a different powder batch, a tighter chamber, a hot day. All of these things are tolerances, when tolerances stack, bad things can happen.

Pressure curves are not linear AND powders have very limited linear response ranges. This means velocity and pressure are only indicative of each over limited ranges of charge with any specific powder.

Does this help you understand why you should never duplicate max listed loads UNLESS you have already worked up to this recipe before AND tested it with safe results before.

The QuickLoad program is a double-edged blade that cuts both ways, it's helpful to experienced reloaders trying to do genuine load development and downright dangerous at the same time for newbie folks looking to jump to conclusions and save some legwork at the range

[SixPointEight]

Good data. Noone's logic states someone should continue past an unsafe condition. But my logic did state you SHOULD have been fine at max load. This is exactly the kind of data I'm interested in.

I'd love to hear additional information about this example/your experience in particular while I've got you in the thread. Were you able to really see that it was caused by pressure? If it wasn't pressure, would you consider that (a non pressure issue that could lead to a flat primer) a safety issue?

Any other cause of flat primers would have shown up in all the other loads because they'd be a rifle issue. Primers began flattening just before that and got to what I consider flat .8 before max. I shot one more set, .6gr below max and had VERY flat primers and cratering. Clearly it was pressure. I suspect that the next step(.4 below max) would have blown primers.

[donger]

I'm interested in data, not rhetoric (there's already plenty of threads with the dogma and rhetoric to explain the qualitative safety requirements when participating in a dangerous hobby.)
.

Not rhetoric but a dose of common sense. By all means start at max load. But as others have stated, there are too many variables in every step of reloading and firing the weapon that I would be too nervous to pull the trigger.

[Cheep]

All of this with a "borrowed rifle"????