I used the data from hodgdons web site and wasn't happy with results asked on the hide and got info on hornady load data for 77 grain bullet finally found decent load 5 shot group .56 which I'm not seeing any pressure issues and the cases are just warm to the touch I'm using 24.5-24.7 grains and getting an average speed of 2557 with the 24.5 & 2615 with 24.7 both have an SD of 12 I'm using wsr primers is there anything else I can do to get this round moving a little faster I know I won't get the published speeds since they are using 24" barrels and I'm using a 1-8 twist larue 18" obr I just think if I had a little more speed these groups might tighten up and then again I may be way off base and should just call this load finished.
- Thread starter Loud&Proud
- Start date
There are too many unknowns in your post above, to give an intelligent answer.
First, is your rifle an AR?
Second, is it chambered for .223 or 5.56mm?
Third, what's your COAL?
Fourth, you weren't happy with Hodgdon's data but you don't say what or why?
Fifth, you got Hornady load data (again for a .223 or a 5.56MM??) for a 77 gr bullet, that Hornady does not make?
Sixth, you don't say what brass your using, and brass matters a bunch in the .223/5.56mm max velocity goal.
Note: .223 Rem SAMMI load data is MAX @ 55Kpsi; 5.56mm is MAX @ 62Kpsi. Almost all published data by bullet and powder makers follows .223 MAX Pressure specifications. For example Nosler publishes online data for both the .223 Rem and 5.56mm. But the loads are identical.......but .223 Rem and 5.56 chambers and reamers are not the same. The 5.56 has a longer lead than the .223 Rem allowing higher pressures, but also remember brass life is not a concern for the military users of the 5.56mm.
First, is your rifle an AR?
Second, is it chambered for .223 or 5.56mm?
Third, what's your COAL?
Fourth, you weren't happy with Hodgdon's data but you don't say what or why?
Fifth, you got Hornady load data (again for a .223 or a 5.56MM??) for a 77 gr bullet, that Hornady does not make?
Sixth, you don't say what brass your using, and brass matters a bunch in the .223/5.56mm max velocity goal.
Note: .223 Rem SAMMI load data is MAX @ 55Kpsi; 5.56mm is MAX @ 62Kpsi. Almost all published data by bullet and powder makers follows .223 MAX Pressure specifications. For example Nosler publishes online data for both the .223 Rem and 5.56mm. But the loads are identical.......but .223 Rem and 5.56 chambers and reamers are not the same. The 5.56 has a longer lead than the .223 Rem allowing higher pressures, but also remember brass life is not a concern for the military users of the 5.56mm.
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It's an AR (LARUE obr 18" 1-8 twist) I'm using once fired lake city brass. I use small base dies and trim to length all brass What I didn't like about hodgdons data was the rounds were terrible on target and velocity wasn't good either these rounds are all loaded to mag length. Hodgdons data has minimum starting at I think 22.5 and going to 24. Nosler doesn't have load data using cfe 223 powder on there sight or in the book that I have. I understand that a .56 group is great at 100yards I am just wanting to make sure I'm not leaving anything out there that might shrink that group a little more.
BobinNC, Please do not take this the wrong way it is NOT meant to be an insult, my posting is about getting the correct information out to people so they understand pressure readings.
There are three methods of measuring chamber pressure, and they are all in pounds per square inch.
(its how we Americans read pressure in the U.S.)
1. The oldest is using a copper crusher pellet called "Copper Units Pressure" or CUP
2. The newer method is with a electronic transducer and it is labeled "PSI" to separate it form the copper crusher method.
3. The European method under CIP (NATO standard) uses the transducer method "BUT" it is located at the mouth of the cartridge case. (Under U.S. SAAMI standards the transducer is located at the mid-point of the case)
All three pressures listed below are the exact same pressure and are just measured three different ways.
1. 52,000 cup
2. 55,000 psi
3. 62,000 psi European CIP/NATO standard
Again ALL three pressures above are the exact same pressure.
Below is the milspec requirements for commercial contract ammunition for the military, again please note that 52,000 cup and 55,000 psi are the exact same pressure. And if the European CIP/NATO method was used it would read 62,000 psi.
MIL-C-9963F
15 October 1976
SUPERSEDING
MIL-C-9963E
12 May 1970
MILITARY SPECIFICATION
CARTRIDGE, 5.56MM, 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.
What this means is very simple, the commercial .223 and the military 5.56 are both rated at the same pressure. BUT because the throats are different if you shoot a .223 in a 5.56 chamber the pressure will be lower than normal. And if you shoot a 5.56 in a SAAMI .223 chamber the pressure will be higher than normal.
Now to add even more confusion, my factory made Savage .223 with a 1 in 9 twist has a longer throat than my AR15 rifles and it is NOT a standard SAAMI throat. The SAAMI only sets basic guidelines and they do not have to be followed, what this means is I can safely shoot military ammunition in "MY" rifle but a short throated .223 will have higher pressures.
Loud&Proud
Part two.
The Hodgdon's loading data you are looking at is for a is for a SAAMI chamber and throat .223 rifle with a 24 inch barrel with a 1 in 12 twist. Your AR15 and its longer throat and 1 in 8 twist will take "MORE" powder to obtain the same velocities. Meaning you will be able to load your rifle "hotter" and still be within normal pressure limits.
I can load my Savage with larger amounts of powder because of its longer throat, meaning the Hodgdons loading data is very conservative if loading for longer throated rifles. Always remember when you see the ejecter circle mark on the base of your brass the pressure is high and the brass is just starting to flow into the ejector in the bolt face. This pressure is not written is stone because the hardness of the brass governs at what pressure the brass begins to flow. Meaning a commercial .223 case might start to flow way before a Lake City case starts to flow because milspec 5.56 brass is harder in the base than .223 cases.
Below is a good link that shows other non-standard chamber freebore lengths, at this link you will see my Savage freebore is .0566 and longer than the AR15 or military freebore or throat.
HOLLIGER ON .223/5.56 CHAMBERS
NJ HiPower - Cartridge Tech Specs
Below is a good link explaining .223/5.56 pressures with charts showing the pressure variations between throats/freebore. What makes this webpage unique is actual pressure testing was done on the two .223/5.56 chambers and throats and it shows actual pressure differences.
5.56 vs .223 – What You Know May Be Wrong
http://www.luckygunner.com/labs/5-56-vs-223/
Loud&Proud, bottom line always try and find the type rifle and chamber the reloading data is from. I have the Hodgdon's reloading magazine and it lists the test firearms used and the website does not for the load and pressure data.
Part two.
The Hodgdon's loading data you are looking at is for a is for a SAAMI chamber and throat .223 rifle with a 24 inch barrel with a 1 in 12 twist. Your AR15 and its longer throat and 1 in 8 twist will take "MORE" powder to obtain the same velocities. Meaning you will be able to load your rifle "hotter" and still be within normal pressure limits.
I can load my Savage with larger amounts of powder because of its longer throat, meaning the Hodgdons loading data is very conservative if loading for longer throated rifles. Always remember when you see the ejecter circle mark on the base of your brass the pressure is high and the brass is just starting to flow into the ejector in the bolt face. This pressure is not written is stone because the hardness of the brass governs at what pressure the brass begins to flow. Meaning a commercial .223 case might start to flow way before a Lake City case starts to flow because milspec 5.56 brass is harder in the base than .223 cases.
Below is a good link that shows other non-standard chamber freebore lengths, at this link you will see my Savage freebore is .0566 and longer than the AR15 or military freebore or throat.
HOLLIGER ON .223/5.56 CHAMBERS
NJ HiPower - Cartridge Tech Specs
Below is a good link explaining .223/5.56 pressures with charts showing the pressure variations between throats/freebore. What makes this webpage unique is actual pressure testing was done on the two .223/5.56 chambers and throats and it shows actual pressure differences.
5.56 vs .223 – What You Know May Be Wrong
http://www.luckygunner.com/labs/5-56-vs-223/
Loud&Proud, bottom line always try and find the type rifle and chamber the reloading data is from. I have the Hodgdon's reloading magazine and it lists the test firearms used and the website does not for the load and pressure data.
Here is my data from my AR-15 rifle set up as a MK-12 clone....18" barrel with 1:8 twist.
Data from an elevation of 3900', temp at 70 deg F, humidity at 18%, pressure at 29.94.
LC brass trimmed to 1.750" and CCI 41 primers.
Using 77 gr SMK and a COAL of 2.260".
My most accurate load is 25.6 gr of CFE223 which has a velocity of 2715 fps.
I tried loads between 24.8 and 25.9 grains but 25.6 was the best.
Once again. use at your own risk but this is what I came up with.
Data from an elevation of 3900', temp at 70 deg F, humidity at 18%, pressure at 29.94.
LC brass trimmed to 1.750" and CCI 41 primers.
Using 77 gr SMK and a COAL of 2.260".
My most accurate load is 25.6 gr of CFE223 which has a velocity of 2715 fps.
I tried loads between 24.8 and 25.9 grains but 25.6 was the best.
Once again. use at your own risk but this is what I came up with.
Thanks for the load data biggin69 I'll continue working on this load and report how it turns out it just might be awhile with the freezing temps up here.
