reloading 5.56 vs .223

[indyblue]

I just read this from a site

Reloading the .223/5.56

Perhaps two of the most popular cartridges in the reloading brass world is the .223 Remington and 5.56 NATO. These have become so popular in today’s shooting world mainly due to the popularity of A…

blog.capitalcartridge.com

The lead of a barrel is the area in front of the chamber, but before where the rifling begins. For the .223 Remington, the lead specification (SAAMI) is 0.085 inches. For the 5.56, the lead specification (SAAMI) is 0.162 inches, or, almost double. This difference is notable.

Because standard 5.56 NATO rounds are produced with higher pressure loads, if it’s fired in a rifle designed for a .223 Remington, the shorter lead in the .223 Remington chamber will further increase the pressure, potentially to an unsafe level. Additionally, manufactured 5.56 rounds are made for the longer lead and, therefore, may have the bullet seated differently. If the bullet from a 5.56 makes contact with the rifling in a chamber designed for a .223 Remington prior to being fired, this too can cause unwanted pressure increases.

Nevertheless, reloaders need to be aware of the powder loads and bullet seating that will correctly accommodate the chamber of the rounds they’re being prepared for. It is important to remember, though, that loading data is NOT interchangeable. Never use reloading data for the .223 when reloading 5.56 brass, or vice versa.

Where would I find such data? I've looked everywhere and 5.56 is not mentioned in the Speer book or Lyman.

Hodgdon data shows starting at 21 min - 23.8 max. I have loaded 40 Sierra 69gr hbpt cartridges in a ladder with IMR 8208 XBR: 10 22gr, 10 22.4gr, 10 22.8gr into .223 cases (once fired PMC bronze)

Should I be worried about any of these? Do I need to start over from the min load? What would I need to change when I get to my swaged pocket 5.56 brass (PMC X-TAC)?

 

[NyleRN]

What chamber are you shooting from? .223 or 5.56?

 

[indyblue]

5.56 chamber.

Maybe I need some CFE223 since 8028XBR is only listed for .223 or wilt it work with 5.56 brass?

 

[NyleRN]

5.56 chamber.

Then don't worry about it. Use whatever brass you want. Trim it to spec, swag the primer pocket if needed. Some manufacturers don't crimp their primers. If your trimmer doesn't chamfer the inside edge of the neck then buy a chamfer tool. Then use your loading manual for data to see what shoots best. Yes, both of those powders will work. You shooting from an AR?

 

[ckcollins2003]

You're over-thinking this.

Yes, the brass is slightly thicker which decreases the internal volume which can bring up pressures faster. However, there are a lot of brass manufacturers and the thickness between the brass is usually slightly different. Reload starting at the bottom and working your way up while looking for signs of pressure. I'll bet you wouldn't notice the difference between shooting the 5.56 brass and the .223 brass with the same load. I have mixed them and loaded them together for years with no issues whatsoever.

 

[Goodcat]

You're over-thinking this.

Yes, the brass is slightly thicker which decreases the internal volume which can bring up pressures faster. However, there are a lot of brass manufacturers and the thickness between the brass is usually slightly different. Reload starting at the bottom and working your way up while looking for signs of pressure. I'll bet you wouldn't notice the difference between shooting the 5.56 brass and the .223 brass with the same load. I have mixed them and loaded them together for years with no issues whatsoever.

This. All of this.

 

[Robert Richardson]

Can't wait for people to look for load data for the 223 Wylde.

 

[AndreusMaximus]

Can't wait for people to look for load data for the 223 Wylde.

I'm sure gun store employees must have a fun time with people asking them for 223 Wylde ammo.

 

[indyblue]

Now y’all are just mocking me.

I know most of the differences are related to the lead to rifling and the pressure differences caused by it as well as the slight dimensional difference of the brass and the fact that 5.56 brass is annealed and the primer pockets are crimped.

I did manage to find a 5.56 NATO section in my Speer book. I was just concerned since it did not list the powder I use and the minimum and maximum loads are different than what are listed for .223.

I also note that my .223 cases with 69 gr BTHP projectiles is somewhat of a compressed load at 22.8 grains, I don’t think I will be able to load any higher of a charge. I have not attempted to load any NATO Brass yet. I am thinking if I cannot fit enough 8208 in the NATO brass, I will need a different powder such as cfe223.

 

[AndreusMaximus]

Now y’all are just mocking me.

I know most of the differences are related to the lead to rifling and the pressure differences caused by it as well as the slight dimensional difference of the brass and the fact that 5.56 brass is annealed and the primer pockets are crimped.

I did manage to find a 5.56 NATO section in my Speer book. I was just concerned since it did not list the powder I use and the minimum and maximum loads are different than what are listed for .223.

I also note that my .223 cases with 69 gr BTHP projectiles is somewhat of a compressed load at 22.8 grains, I don’t think I will be able to load any higher of a charge. I have not attempted to load any NATO Brass yet. I am thinking if I cannot fit enough 8208 in the NATO brass, I will need a different powder such as cfe223.

Lol, sorry, didn't mean to make fun of you.

Your thinking makes sense; if you've worked up a max load using 223 brass, it's definitely possible that 556 brass will cause an increase in pressure due to slightly lower case volume and other dimensional differences. This of course can also be true when switching between brass from different manufactures, even if it's all 223 or 556. Working up the load again is always safest when changing any component, but as a general rule of thumb it's safe to use starting loads for 223 in a 556 chamber, regardless of what brass you're using.

 

[indyblue]

So, in other words as long as I’m using a 556 chamber I should be OK using the faster burning 8208?

 

[NyleRN]

So, in other words as long as I’m using a 556 chamber I should be OK using the faster burning 8208?

Yes

 

[NyleRN]

If you're loading at the top of the recommended charge weight then shoot 1 round at time and check your fired brass case. Check and see if the primer is popped. If it still has the normal indentation from the firing pin and it's still seated then you're gtg. I use varget and IMR 4320 for my AR loads

 

[NyleRN]

Also, if you're loading towards the top remember that powder temperature stability is a real thing. I like certain powders cause I can load them when it 50 outside and still shoot when it's 95 and not have to worry about pressure spikes due to ambient temp changes

 

[indyblue]

Also, if you're loading towards the top remember that powder temperature stability is a real thing. I like certain powders cause I can load them when it 50 outside and still shoot when it's 95 and not have to worry about pressure spikes due to ambient temp changes

And this is why I like 8208 XBR, it is hailed as one of the most temp stable powders.

Aaaand, this is why I hate the Internet sometimes. I have now read three articles that state the following:

The 5.56 also has a longer throat with a difference of .125 inches in length when compared with that of the 223 Remington bullet. The longer throat allows more holding capacity for gun powder in the 5.56, thus implying that it has a higher performance as compared to the 223 Remington.

What the hell is the throat of a case? do they mean the neck since the throat is part of the chamber/barrel.

 

[NyleRN]

Yeah, the throat chamber in a 5.56 is longer. That's why you can shoot 5.56 or .223 in a 5.56 chamber and not the other way around

 

[indyblue]

I know the chamber throat is longer, but how does that allow for 1gr more powder in the case?

So if a 5.56 case is supposed to be thicker resulting in less case capacity, how would you get 1 extra grain into a 5.56 case?
This is very conflicting info. I suppose that's why the powders specified for 556 differ from 223, for the difference in volume various powders occupy. I am guessing 556 powders can fit more powder in a smaller case volume.

This might mean I'll potentially need to use another powder for my 556 loads and relegate the 8208XBR to 223 purposes.

Thanks all for the responses to this subject.

 

[NyleRN]

Not all powders meter the same
Not all powders have the same burn rate
I could take 25gr of powder X under a 55gr projectile and get 2500fps. Then take 25gr of powder Y with that same projectile and get 2650fps.

 

[indyblue]

NOTE: We can assume I'm only using a 5.56 chamber so any 223 reference is moot and can be left out for now.

Not all powders meter the same

What does that have to do with my question? Powder is measured by weight not volume and I carefully verify I'm dropping the weight I expect for each powder.

My point was, from my research it is stated that 5.56 is allowed 1gr more than .223 due to the case throat (whatever that means) and that that difference in the amount of powder is the primary reason for the higher case/chamber pressures (in a 5.56 chamber). If the case volume of 5.56 is less than .223 then the volume the powder occupies must be the difference that allows that 1 extra grain to fit in a smaller space. I cannot fit more than 22.8 gr of the extruded 8208 into a case due to its volume, so in order to work up any loads closer to the max of 23.1gr I will need to select a powder with a density and grain geometry that will fit, regardless of burn rate.

I am not trying to purposely use the MAX load, I'll only do the if that's what yields the best results in my ladder testing. I started with 22gr (21 is min) and worked up 4 sets of loads from there and I had to stop when I got to 22.8 because no more 8208 will fit in my cases.

 

[55fairlane]

If I may offer some advice, A) the projectiles your using, use that manual,i.e. I use Hornady, use Hornady manual. If load data isn't listed, email them.
B) 8208XBR is an awesome powder for your service rifle load. Yes it is faster then varget or cfe223 , but neither of those would offer satisfactory results in ,y service rifle.
C)load development is only 10 shots. Load in .2 increments down from the max load.(so example 30.0 , 29.8 , 29.6 ect) shoot thru your clock, you will find 3 shots on the low end with nearly identical velocity & same on the high end. The lowest powder charge on the high end is were you want to load at.

Aaron