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Discussion Starter #1
I have been reloading for the 223/5.56 for a couple of months now, there is plenty of 223 data but not as much 5.56 data. The only place where I have seen data for both is western powders, it's nice to be able to compare loading data between the two. Their data shows that 5.56 cases can be loaded with at least a grain or more powder with the same bullet type and weight. I have an accurate load consisting of 25.5 gr of H-4895 with the 50 gr Nosler BT varmit in 223, am I correct to assume that I can increase the powder charge when using 5.56 cases, unfortunately Hodgdon does not have data for both. Any help or advice is appreciated.
 

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Hornadys 8th edition lists 5.56 data BUT the data starts for a 68gr bullet. I've compared commercial cases to lake city cases and lake city has less case capacity than commercial. I don't believe you can fit enough 4895 in a case to run into a pressure situation, unless you have the bullet close to the lands. If you're switching cases it's best to start over.
 

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It's not about the cases. It's mainly just that the pressure standards aren't the same on paper. It's due to the instrumentation used by SAAMI and NATO not giving the same pressure readings firing the same cartridge.

SAAMI says .223 Remington is limited to 52,000 CUP or 55,000 psi maximum average pressure (MAP) for copper crusher or conformal Piezo transducer, respectively. NATO puts the 5.56 at 3800 bar, or 55,114 psi by copper crusher, and 4300 bar, or 62,366 psi MAP by their type of Piezo transducer. All four reading differences result from firing the same lot of reference ammunition in all four measuring systems.

The differences in the reading results have to do with pressure port locations, handling techniques, and test equipment differences. Lots of folks mistakenly think it means the real absolute pressures are different, and that you should therefore be able to load 5.56 higher, but they actually are not different pressure standards except that SAAMI and CIP only concern themselves with maximum pressures, while NATO adds gas port pressures and muzzle velocity windows into the mix. The proof is that all the European made .233 Remington is loaded to the CIP standard, which copies NATO, and is 62,366 psi MAP, using instrumentation more similar to NATO's. Yet if you buy some Russian or Czech or other European .223 ammunition loaded to that standard, it works just fine in our .223 chambered rifles.

The other thing that fools people is the perception that military ammo is warmer. It's actually just that a lot of commercial ammo is loaded milder than required, while the military stuff, having to meet minimum gas port and velocity requirements, is loaded to a narrower window and are not loaded down as far.
 

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Discussion Starter #4
Uncle Nick, do you think I can increase my powder charge from 25.5 gr H 4895 if I use 5.56 cases? I am getting 3016 average velocty with this load with 50 gr Nosler Bt using 223 winchester cases, CCI 400 primer, this is out of a 16 barrel.
 

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Pick up a copy of the Hornady "handbook of cartridge reloading" 9th edition, it's got loads for .223, .223 service rifle, and 5.56x45 NATO. The 5.56 listings have loads for 55gr, 60gr, 68gr, 70gr, 75gr, and even 80gr bullets. I think cabelas sells the book for about $40. But don't take my word on the price. This is the book where I get most of my loads from. I prefer Hornady products over most others. But they have plenty of data that you won't regret the purchase.

Edit: and fastfreddy, I do not think there is a slight bit of difference between 5.56x45 brass and .223 rem brass. (Besides the head stamp). I've used .223 brass to load 5.56 loads without a single problem in thousands of rounds. Some people will say that 5.56 brass may be thicker or some such. But I've come to understand that the main difference between the two isn't actually the cartridge so much as it's actually the chamber they are fired out of. I was taught that a 5.56x45 chamber is a little looser tolerance than .223 allowing it to handle slightly higher pressures or some such. Something about head spacing I beleive.
 

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There should be virtually no difference in the brass in terms of capacity - but you might check capacity if you are changing brass lots. It can affect the sweet spot on your loads.

There is a slightly longer throat on a 5.56 chamber. That can affect pressures, but it can affect pressures with any chambering to cut a longer throat (think freebore).

Headspace is identical for all practical purposes (tolerances are a bit different). E.g., once you set up your dies for your chamber, you are good to go.

Don't think you can hot-rod due to different brass headstamps. Re-read Nick's post.... find the sweet spot for accuracy within the published data, and just enjoy. The .223 is not a hot rod and never will be.
 

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Discussion Starter #8
I loaded up some rounds using once fired LC 13 cases with the following charges of H 4895, 25.7, 25.9 and 26.1, I never got to fire the 26.1 loads. The average speed for the 25.7 gr load was 3086, the 25.9 load averaged 3108, with this load the primers were flat as a pancake with heavy cratering, the primers fired with the 25.7 gr load looked fine with only slight cratering. My 223 loads with 25.5 gr average 3012, I am using Winchester 223 cases with the same primers, It appears that a slight increase in powder and a different case does make a huge difference, thinking of giving up on this idea because I am gaining very little velocity, does not appear to be worth the effort. I appreciate the help.
 

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There should be virtually no difference in the brass in terms of capacity - but you might check capacity if you are changing brass lots. It can affect the sweet spot on your loads.

There is a slightly longer throat on a 5.56 chamber. That can affect pressures, but it can affect pressures with any chambering to cut a longer throat (think freebore).

Headspace is identical for all practical purposes (tolerances are a bit different). E.g., once you set up your dies for your chamber, you are good to go.

Don't think you can hot-rod due to different brass headstamps. Re-read Nick's post.... find the sweet spot for accuracy within the published data, and just enjoy. The .223 is not a hot rod and never will be.
Your 16" tube is limiting velocity, not your brass. The 5.56 / .223 loses about 50FPS/inch of barrel from 20" on down.

Barrel Length Studies in 5.56mm NATO Weapons
 

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Uncle Nick, do you think I can increase my powder charge from 25.5 gr H 4895 if I use 5.56 cases? I am getting 3016 average velocty with this load with 50 gr Nosler Bt using 223 winchester cases, CCI 400 primer, this is out of a 16 barrel.
You need to quit worrying about which brass you are using (.223 or 2.56) because there is really no difference in the brass. It depends on what chamber you are reloading for. If you are shooting a rifle chambered in .223, do not use the 5.56 data regardless of which brass you are using, use the .223 reloading data.
 

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Discussion Starter #11
You need to quit worrying about which brass you are using (.223 or 2.56) because there is really no difference in the brass. It depends on what chamber you are reloading for. If you are shooting a rifle chambered in .223, do not use the 5.56 data regardless of which brass you are using, use the .223 reloading data.
My rifle has a 5.56 chamber, so really when reloading my own it does not make a difference which brass I use, however with factory loads it makes a bigger difference because 5.56 loads are hotter. Western powders shows data for both 223 and 5.56, most 5.56 loads show a grain or more increase in powder charge so these loads are based on the chamber not the brass, is this correct.
 

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My rifle has a 5.56 chamber, so really when reloading my own it does not make a difference which brass I use, however with factory loads it makes a bigger difference because 5.56 loads are hotter. Western powders shows data for both 223 and 5.56, most 5.56 loads show a grain or more increase in powder charge so these loads are based on the chamber not the brass, is this correct.
that is absolutely correct
 

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that is absolutely correct
Actually . . . . not completely. In addition to chamber size and shape, the twist rate is also a factor because a faster twist increases resistance and increases chamber pressure. For instance, Ramshot's vol 5.0 load data (available for free download HERE) shows one set of data for .223 with a 1:14 twist and a higher set for a 5.56 and a 1:7 twist.
 

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Discussion Starter #14
Well, at least now I know that my near max loads using 223 brass can't be improved as far as velocity goes, this information probably saved me from high pressure issues, thanks.
 

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Ammoguide.com

I have been reloading for the 223/5.56 for a couple of months now, there is plenty of 223 data but not as much 5.56 data. The only place where I have seen data for both is western powders, it's nice to be able to compare loading data between the two. Their data shows that 5.56 cases can be loaded with at least a grain or more powder with the same bullet type and weight. I have an accurate load consisting of 25.5 gr of H-4895 with the 50 gr Nosler BT varmit in 223, am I correct to assume that I can increase the powder charge when using 5.56 cases, unfortunately Hodgdon does not have data for both. Any help or advice is appreciated.
Check out ammoguide.com. Join and get all the load data you ever wanted plus! I have a number of 5.56x45 loads on there.
 

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Discussion Starter #16
Frhunter 13, I went out this morning and shot some groups using the same powder charge ( 25.5 gr H 4895) that I used with 223 cases, best group measured .478, worst group .969, muzzle velocity averaged 3061 vs 3012 with the 223 cases, the LC 13 cases are probably the reason the speed increased. Cases did not show any signs of excessive pressure, thanks for the Information
 

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Pick up a copy of the Hornady "handbook of cartridge reloading" 9th edition, it's got loads for .223, .223 service rifle, and 5.56x45 NATO. The 5.56 listings have loads for 55gr, 60gr, 68gr, 70gr, 75gr, and even 80gr bullets. I think cabelas sells the book for about $40. But don't take my word on the price. This is the book where I get most of my loads from. I prefer Hornady products over most others. But they have plenty of data that you won't regret the purchase.

Edit: and fastfreddy, I do not think there is a slight bit of difference between 5.56x45 brass and .223 rem brass. (Besides the head stamp). I've used .223 brass to load 5.56 loads without a single problem in thousands of rounds. Some people will say that 5.56 brass may be thicker or some such. But I've come to understand that the main difference between the two isn't actually the cartridge so much as it's actually the chamber they are fired out of. I was taught that a 5.56x45 chamber is a little looser tolerance than .223 allowing it to handle slightly higher pressures or some such. Something about head spacing I beleive.
Amazon sells the book for less I just got the new one from them last week. About 26 bucks from them for the 9th edition...
I am using LC Brass and loading an even 25 grs of TAC under the 62 gr pulled green tips (M855 round)and they are right at the factory numbers for everything. Cannot remember right now the numbers, used a neighbors chrono last year when I loaded them up
Lake City brass is about a full gr and a half smaller than commercial brass for powder volumes.
 

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223 and 5.56 brass are the same except that the thickness and weight of the alloy can vary from one manufacturer to another and even batch to batch and the 5.56 may have a longer neck. I bought 1500 once fired nato 5.56 LC cases a few years ago and conversion has required trimming to 223 length and reaming the crimp fron the primer pocket. After that they have been excellent.

The difference between 223 and 5.56 chamber is the neck length is longer. This means 223 can fire safely in a 5.56 chamber but the neck of 5.56 brass may bottom out in a 223 chamber causing unsafe pressure spikes.
 

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Actually . . . . not completely. In addition to chamber size and shape, the twist rate is also a factor because a faster twist increases resistance and increases chamber pressure. For instance, Ramshot's vol 5.0 load data (available for free download HERE) shows one set of data for .223 with a 1:14 twist and a higher set for a 5.56 and a 1:7 twist.
COSteve,

Be wary of the 5.56 data in the Western load manual. I just learned of it last week and immediately called Western because that data was developed under the false premise that the NATO/CIP pressures are higher than SAAMI pressures. They are not. They are identical.

The U.S. military (i.e., Lake City or others making military ammo on contract) use the SCATP 5.56 procedure for loading NATO compatible ammo. This uses the SAAMI type conformal piezo transducer. If you put NATO reference loads into a conformal transducer the readings average 55,000 psi. European manufacturers of NATO ammo use the EVPAT 5.56 procedure. This employs a channel piezo transducer. So does CIP. The main difference is that EVPAT samples the gas pressure just ahead of the case mouth, while CIP drills holes in its cases to sample them 25 mm forward of the outside surface of the case head. Unlike the conformal transducer, which reads pressure over top of the brass case, the channel transducers sample the gas directly, the same as the copper crusher system did. If you shoot that same reference load in a channel transducer that averaged 55,000 psi in the conformal transducer, it averages 4300 bar (62,366 psi) in the channel transducer.

The mistakes Western made was assuming there was a real difference in the absolute pressures in the two cartridges and that a conformal transducer would measure them accurately. As a result, all their 5.56 loads, made to the pressure that should be read on a channel transducer, were read on a conformal transducer, and so they produce loads that would read close to 71,000 psi on the channel transducers.

When I explained this to Western's technician, the response I got was "oh". And then: "I'll pass that along". Clearly they were unaware the pressure difference in the SCATP and EVPAT maximum average pressure were instrumentation artifacts and not real.

If you doubt any this, look at the original copper crusher specs for the NATO cartridges. They are within a statistically insignificant difference from one another because under that standard everyone was drilling cases and measuring in a much more similar manner. For M193 ball ammunition, both the U.S. military and SAAMI have 52,000 units of pressure by copper crusher, while the Europeans, with their metric version copper crushers use 3700 bar, or 53,664 psi (by copper crusher, a.k.a., CUP in SAAMI terminology).

From MIL-C-9963F, Cartridge, 5.56 mm Ball, M193:
3.7 Chamber pressure.

3.7.1 Measurement by copper-crush cylinder. -The average chamber pressure of the sample cartridges, conditioned at 70° ± 2°F, shall not exceed 52,000 pounds per square inch (PSI). The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 58,000 PSI.

3.7.2 Measurement by piezoelectric transducer. -The average chamber pressure of the sample cartridges, conditioned at 70° ± 2°F, shall not exceed 55,000 PSI. The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 61,000 PSI.

3.8 port pressure.

3.8.1 Measurement by copper-crush cylinder. -The average port pressure of the sample cartridges, conditioned at 70° ± 2°F, shall be 15,000 PSI ± 2000 PSI.

3.8.2 Measurement by piezoelectric transducer. -The average port pressure of the sample cartridges, conditioned at 70° ± 2°F, shall be 14,400 PSI ± 2000 PSI.

The error will still be below proof pressures on either side of the pond, but it will be harder on a gun than normal. Since most bolt guns are designed to withstand pressures with wider case heads than the .223, I don't expect them to be bothered by it much, other than faster throat erosion. However, gas systems on the mouse guns may be unhappy about it. Notice the military spec includes gas port pressure ranges, while the commercial procedure does not.
 

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Very interesting information. However, not consistent with the US Army's own Tech Manual, TM 43-0001-27, ARMY AMMUNITION DATA SHEETS, SMALL CALIBER AMMUNITION, FSC 1305 dated April 1995.

First some background. Hodgdon's H335 powder is the commercial equivalent Military WC-844 powder which is used by the military for loading their 5.56 family of ammunition. Therefore, a comparison of like loads between Hodgdon's H335 and military WC-844 powders should be the same. (However, caution is always recommended that one work up each new powder / component load to insure the rounds produced are safe in your firearm.)

Hodgdon's web reloading guide lists a 25.3 grns for a 55grn bullet developing 3,203ps out of a 24" 1:12 barrel with a max load developing 49,300 cup. That's at odds with page 10-3 of TM 43-0001-27 Army Ammo Data Sheets which lists the information for "CARTRIDGE, 5.56MM, BALL, M193" (55grn FMJ ammo). In it the powder listing is WC 844 a with charge weight of 28.5 and a velocity of 3,250 fps, 15 ft from muzzle and a max chamber pressure of 52,000 ps. Further, the same loadings are listed for the M196, 55grn tracer round as well.

Therefore, the US Army's spec is 3.2grns of WC-844/H335 more than Hodgdon's max spec. All M193 ammo is designed for M16/M4 class weapons from which the AR15 is a semi-auto version of.

Similarily, Hodgdon's web reloading guide lists a 21.4 grns for a 62grn bullet developing 2,887ps out of a 24" 1:12 barrel with a max load developing 53,600 psi. That's also at odds with page 10-19 of TM 43-0001-27 Army Ammo Data Sheets which lists the information for "CARTRIDGE, 5.56MM, BALL, M855" (62grn penetrator ammo). In it the powder listing is WC 844 with a charge weight of 26.1 gr and a velocity of 3,025 fps, 78 ft from muzzle and a max chamber pressure of 55,000 psi.

Again, the US Army's spec is 4.7grns of WC-844 more than Hodgdon's max spec. All M855 ammo is designed for M16/M4 class weapons from which the AR15 is a semi-auto version of.

These examples demonstrate a few things your explanation overlooked. First, the commercial .223 load data assumes a .223 chamber while the US Army's load data assumes a 5.56 chamber. Second, the commercial .223 load data assumes a lower max pressure (in part due to the different chamber) than does the US Army's load data.

I have a 20" Wylde chambered (variation of a NATO chamber), 1:9 RRA A4 AR15 that I shoot 68grn Hornady bullets through exclusively (my rifle likes Horndays better than 69grn Sierras with TAC powder) and my charge weight for TAC is 25.1grns (over the max listed for .223 chambered rifles but under that listed for NATO chambers in Ramshot's load data). This rifle has thousands of rounds through it and is used for long range (400-500yd) shooting at my favorite targets, apples. It performs perfectly.
 
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