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223/5.56 loading data

38K views 34 replies 18 participants last post by  unclenick 
#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.
 
#2 ·
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.
 
#3 ·
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.
 
#10 ·
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.
 
#5 · (Edited)
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.
 
#17 ·
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.
 
#7 ·
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.
 
#9 ·
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
 
#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.
 
#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
 
#18 ·
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.
 
#20 ·
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.
 
#21 ·
costeve

This is consistent with the difference between 223 and 5.56 mil-spec loadings that are discussed on ammoguide. The mil-spec guns are stronger. Most manufacturers will not list mil-spec loadings in fear they will be applied to the 223. I run a mil-spec load in my M4, which it likes very much.
 
#22 ·
Don't read too much into comparing WC844 data to H335 data.

Every lot of WC844 is not identical to every lot of H335 just by the inference that H335 is surplus WC844.

I have one particular lot of WC844 (will provide the lot # if asked) and I can assure you that particular lot is WAY slower than any commercially sold lot of H335. Some might be slower, some might be faster, but mine is off by enough that you'd really notice it.

Works great, but I have to treat it like it is an entirely different powder than H335.

Why is it that much different? I don't know.

I do agree that freebore will for sure affect pressures, and should reduce them a bit. That alone should make the military 5.56 "max" data just a tad more than the civilian .223 "max" data. But not by a whole lot.
 
#24 · (Edited)
i recently discovered that 223 Wylde is a 5.56 NATO chamber with a 223 Rem throat area. ( See Wikipedia) that will chamber 223 Rem or 5.56 NATO ammo interchangeably.

Just throwin that out for you.:p

THis is a great thread and I have black and bolt rifles and a 14 in their respective NATO and 223 chambers.

Just don't fire 5.56 NATO in a 223 Rem gun I have read and heed. That includes the reloads to the respective reloads appropriate chambers.

The 14 eats either ammo according to the owners manual.

223 - 5.56 diameter projectiles are fabulous!!!:D
 
#26 · (Edited)
A 5.56 chamber will fire .223 without a problem. What the .223wylde does is allows it to shoot both accurately. What I and many people experience when shooting .223rem in their 5.56x45 chambered rifles is poor accuracy. It's about twice the size groupings out to 100 yards. I can get a 1-1.5" group out of my colt with a 5.56 cartridge, 1:7 twist rifle. A similar load in .223 factory loads will yield slightly larger groups for me, somewhere around 2-2.5". The .223 Wylde barrel my bud's dad has, has shot both very accurately from what he's said.(he has a heavy barrel and he claims shots touching at 100 yards easy) That's my understanding of the Wylde barrel, it's going to be what I get my varmint rifle chambered in.
 
#25 ·
Call the Sierra Bulletsmiths and ask them??

the # used to be 1 800 bulletsmiths.. better check it. They give good advice and it DONT have to be about Sierra bullets. They dont discriminate.

Otherwise check the website for your powdermaker and see what they recommend. If they dont have 5.56 data email em and ask.
 
#28 ·
I have a RRA Lar 15 and it's the most accurate rifle I own, I have made up at least a dozen loads using various powders and bullet brands. My most recent load 25.5 gr of H4895 and the Nosler 50 gr varmit BT shot two groups measuring .978 and .456. Most accurate load so far is 25 gr Benchmark, 52 gr Sierra MK bullet, best group measured .256, I was using LC 13 cases and CCI 400 primers. It appears benchmark powder and Sierra bullets are the most accurate combination.
 
#30 ·
My 1 in 9 twist Savage bolt .223 shoots anything from 50 to 69 great, if I do my part with the shooting and the reloading. I haven't tried anything below 50, but I did try some 77 grainers and they began to keyhole.
 
#32 ·
I have shot 60 grain Nosler Partitions, but found them too expensive for my target shooting. I only shot one box of them a few years back. I only tried Varget, between 24.5 and 26 grains. My best accuracy (1 1/2 inches at 100 yards) was with 26 grains. I didn't work on it too long because 55 and 60 grain V-Maxes and Ballistic Tips were much cheaper. So I am not an expert on the Partitions in .223. But my best accuracy and also the least expensive jacketed bullets I have used have been Nosler 55 grain tipped Varmageddons.
 
#33 · (Edited)
Wow, great thread!! I have a Mil-Spec AR15. I will now have to get the build specs from the manufacturer.
Besides that I am reloading a lot of random brass all trimmed to .223 Specs. I am using CCI400 primers and (if it's still good) 24 gr. IMR 4064 powder, Hornady 55gr. fmjbt bullets.
Do I need to worry about pressure with this smaller chg. Just plinking at 100yd.

Thanks.
 
#34 · (Edited)
223 vs 5.56x45

Military cases are heavier, (more brass with slightly less volume capacity). Outside case dimensions are identical. Military ammunition is typically loaded with heavier bullets, (62 grains is the most common). The the leade, (throat), is longer in the 5.56x45 mm chamber which creates a rifle that is less problematic but likely not as accurate. Most accuracy fanatics try to reduce bullet runout to improve accuracy. Military cases will handle higher pressure, however, many AR type rifles are capable of firing either round. I don't reload military ammo because of the difference in the cases. Military ammo has crimped primers so the primer pocket needs to be reamed to facilitate re-priming, (not a big deal since it is a one time step). The main reason I don't reload military cases is because the case volume is slightly different due to the heavier military case; this leads to a slight change in pressure between .223 and 5.56x45 brass when fired with identical powder charges. If you don't care about accuracy when shooting you can go ahead and mix cases; if accuracy matters stick with one or the other. A side note 5.56X45 factory ammo should not be fired in a firearm designated for .223 only. If I'm scrounging range brass I sort cases by manufacturer and don't mix during a shoot, (just because that's how I am). Some reloaders weigh every case and cull anything with too much variance within the same case manufacturer.
 
#35 · (Edited)
Military cases are heavier, (more brass with slightly less volume capacity).
That's only true in 7.62. In 30-06, the military and commercial capacity differences are negligible for most applications. In 5.56, LC actually has slightly more internal capacity than its commercial counterparts. You will find a good comparison of weight and case water overflow capacity by scrolling about 1/3 of the way down on this page.

Notice the correspondence between weight and capacity doesn't always track. The Guatemalan IMG brass weighs 95.4 grains and has 30.1 grains of capacity, while the WCC99 is slightly heavier at 95.5 grains but has a slightly greater capacity at 30.5 grains. I've found with 7.62/.308W brass in the past that a difference in capacity is only predicted within about 20-25% by weight difference. You just have to measure water capacity if you want to be sure.

The advantage the military brass has in most semi-autos is the heads are double-struck and significantly harder than most commercial brass. This withstands hard extraction better and with less rim bending than softer brass does. An exception is Starline 5.56 brass which has harder heads, too.

The poor weight-to-volume correspondence occurs for two reasons. One is different brands use different alloys with differences in density. But the bigger contributor is the exterior tolerances for the head. Even if you keep the height of the head the same so it doesn't impact internal capacity, the differences in diameter, rim thickness, rim relief angle, extractor groove depth, and extractor relief angle can add up to significant weight differences. I've calculated it for 7.62/308W size head before and it came out to over seven grains of difference being possible without changing internal capacity. Real cases never get all the way the tolerance extremes, but seeing three or four grains difference from the head tolerances is well within the expected range of variation.

The differences in 5.56 and 223 pressure have a lengthy and convoluted history. The cartridge was originally developed at 52,000 CUP, and when Remington commercialized it as the 223 Remington in 1962, that pressure number is what they used, together with the original chamber dimensions. Over the next couple of years, in order to maximize the number of rounds fired between failures, the military altered the chamber dimensions, making the chamber bigger, and when it finally made the cartridge an official military cartridge as M193, that chamber expansion had dropped the pressure to 50,000 psi by copper crusher (what SAAMI and the Aberdeen lab techs call CUP, but the military tech manual editors insist on calling psi, just expecting everyone to know what instrument measured the pressure, leading to a great deal of confusion).

So, here's the really confusing part. When the U.S. pushed NATO to adopt the same cartridge, NATO found it didn't pass their minimum standards for 350 m penetration and accuracy. So they got FN to develop the SS109 with 62-grain projectile and operating at a pressure of 55,000 psi by copper crusher (CUP). When SAAMI took the reference ammunition for the 223 Remington that was developed in copper crushers and fired them in the conformal piezoelectric transducer, the peak number they got was 55,000 psi (by transducer). Those two different unit numbers, both with the same magnitude of 55,000 have caused a lot of misunderstanding of the differences in the test standards and what is expected of a cartridge. Also, as powders have gotten better, the number that allows reaching the military requirements for velocity and gas port pressure with lower peak pressures has increased. As a result, what you really get by way of pressure in 223 and 5.56 ammunition is often not really different. This test shows the same ammunition fired in two AR's and one sporting rifle, and the two ARs gave the highest and lowest pressure reading with the sporting rifle was in the middle.

There is no question the SS109 and its U.S. counterpart, the M855 should be running about 10% higher in pressure than the 223, but they don't always. In a SAAMI conformal pressure transducer, they should read about 58,000 psi. In the NATO EPVAT system using Kistler pressure transducers sampling propellant gas through a channel (aka, a channel transducer) these same cartridges read a maximum of 4300 bar or 62,366 psi. The CIP adopted that number and uses the same channel transducer except where the NATO transducers sample gas from the bore just in front of the case mouth, CIP uses a point 25 mm forward of the head and samples pressure through a hold drilled into the case. This channel location tends to read a couple thousand psi higher than the NATO case mouth location, so European commercial 223 Remington can be expected to read about 60,400 psi in a NATO test barrel, and about 56,200 psi in a SAAMI conformal transducer. I have no way to confirm those numbers; they are just based upon averaging published values. It would be fun to have a complete set of the three equipment setups to see the differences in action, but I can confirm I have one declassified military document that shows conformal pressure transducer readings of 58,100 psi is used for one particular 5.56 round.

Today, the new "green" military round with lead-free everything is the M855A1. It is being loaded to even higher pressures than the SS109 and original M855 and is reported to cause increased throat wear. Personally, knowing that SAAMI pressure variation allows individual outlier rounds to reach up to 18% above the SAAMI Maximum Average Pressure (MAP; the number we usually see used as a pressure limit) and that and any of the above-mentioned pressures are is still below proof pressures, I don't have a problem shooting M855 in a 223 chamber. I just recognize that I am going to see the barrel wear out faster with a steady diet of that.
 
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