223/5.56 Reloading Question

Gadsden

Sharpshooter
Supporting Member
Special Hen Supporter
Joined
Nov 18, 2021
Messages
1,560
Reaction score
4,950
Location
Somewhere west of Tulsa
Okay let me begin by saying I am very new to reloading and I know I still have a LOT to learn, but I’ve read that a rifle rated for 223 only cannot, or should not, be used to fire 5.56 ammo. In my case my rifle is a 5.56 so that is not an issue.

My question involves reloading for the pressures obtained when shooting 5.56 ammo compared to a 223. When looking at Lyman’s 50th anniversary handbook I see only how to reload for 223. I then referred to my Hornady Handbook which breaks down, not only, how to reload not only for 223, but a 223 Service Rifle and 5.56 too. My confusion arises when I compare Lyman’s manual to what I’m seeing in the Hornady’s manual.

For example, a 223 using a 75 gr. Jacketed A-Max and Varget powder the Lyman manual tells me the suggested starting weight of powder is 23.0 gr. with a maximum load of 25.6 gr.

Going to Hornady’s manual, under load data for 5.56 using the same bullet (75 gr. Jacketed A-Max) and powder (Varget) I see a starting weight of 21.8 gr and a maximum of 24.6 gr.


Which brings me to the crux of my question which, other than curiosity I really have no idea why I’m asking since it doesn’t effect me, but it really is nagging at me so I hope someone here can offer some insight. Obviously the data contained in the two manuals overlap so why wouldn’t the maximum load of 25.6 gr found in Lyman’s manual deliver pressures equal to 5.56 NATO? And wouldn’t someone using a rifle rated for 223 only experience potential problems?
 
Last edited:

okierider

Sharpshooter
Staff Member
Supporting Member
Special Hen Moderator Moderator Supporter
Joined
Dec 26, 2016
Messages
7,116
Reaction score
8,936
Location
OKC
Not sure but you may want to look at the volume difference between the 223 case and the 556 case . Could be do to case thickness in the 556 you can only get that much Varget in the case.
1645922894204.png
 

swampratt

Sharpshooter
Supporting Member
Special Hen Supporter
Joined
Nov 3, 2010
Messages
9,230
Reaction score
7,119
Location
yukon ok
I have 2 .223 rifles and I have shot 5.56 and .223 and but neither of those store bought calibers can match my reloads in accuracy or drop.
My loads kick harder than either of them knowing kick is not a positive sign of pressure.

I believe original 5.56 was rated in CUP and tested that way and the .223 was tested in PSI.

I have read hours of stuff on the 2 and read many tests that measure many different 5.56 and .223 ammo.
The conclusion was some .223 had more pressure than 5.56.
and some 5.56 had more pressure than some .223 talking store ammo here.

I actually tested different primers to fail and pressures were very high.
 

turkeyrun

Sharpshooter
Special Hen
Joined
Feb 11, 2013
Messages
5,455
Reaction score
2,447
Location
Where I am is where I'm at
I have a 5.56 and a .223. Factory loadings of both calibers have been shot in both rifles, with not problem.

For my reloads, I used .223 brass only. I separate the 5.56, due to less case capacity. Crimped primers influence the decision, also.
 

Latest posts

Top Bottom