Max load in 223

[WyoMSRHunter]

I am currently working up some loads for 223 rem for a MSR using 60Gn Hornady Vmax and H335 powder. The Hornady manual states the max load is 22.9Gn to give 3000fps. I used 22.5Gn and was running 2550fps in my rifle so I increased to 23.0Gn and am running 2600fps. I saw a load on loaddata.com for 25Gn which they called max and most accurate. My question is should I move on up looking for pressure or cycling issues or call the Hornady max listed as max.

 

[venatic]

Hodgdon shows 24.0 gr max so I think you can move up and I would while as you said watch for issues. Remember when it gets hot pressures will go up with H335 but I run 60 gr bullets at around 2900 so you are not there yet.

 

[shinbone]

Hmmm . . . I just started working with the same combination - .223Rem/H335/V-Max 60gn in a Kimber Montana. I am running pretty fast - 26.8gn/3350fps - and still not seeing any pressure signs, even under a jeweler's loupe. This with Starline brass. I wonder if I should back off, even though the cases don't show any signs of stress . . .

 

[338LAPUA]

I would keep going and watch for pressure signs. Every gun is different that is just what they got with their test rifle. Barrel length will factor in too.

 

[WyoMSRHunter]

Thank you everyone for your input. I'll go up to 24 and maybe slowly up to 25 but will probably stop there.

 

[WyoMSRHunter]

Hmmm . . . I just started working with the same combination - .223Rem/H335/V-Max 60gn in a Kimber Montana. I am running pretty fast - 26.8gn/3350fps - and still not seeing any pressure signs, even under a jeweler's loupe. This with Starline brass. I wonder if I should back off, even though the cases don't show any signs of stress . . .

Great minds think alike...

 

[venatic]

I looked back which was way back over 10 years ago when I used H335 in 223 and I had worked up to 25.5 but in summer that load would blow primers so I lowered to 24.4 and then switched to N133 and more recently to AR Comp. Much more tolerant to high temps.

 

[Clark]

Here is me working up 223 with H335 and 55 gr

223 55 gr max published load Hodgdon 25.3 gr H335

unfired, extractor groove .329"
28 gr, extractor groove .329", 11% overload 69 kpsi
29 gr, extractor groove .329", 15% overload 80kpsi
30 gr, extractor groove .3295", 19% overload 92kpsi
31 gr, extractor groove .3320", 23% overload 106kpsi

If you do the same sort of test on other case head designs, a hierarchy contrary to SAAMI registered max average pressure emerges:
1) 6mmBR case head too strong to damage, primer fails as limit
2) 223 case head is very strong
3) Belted magnum case head is strong, but not as strong as 223
4) Mauser case head, 270, 250Sav ect, very strong but not as strong as belted magnum
x) 10mm handgun, 25acp handgun, 30 carbine... very weak case head, primer pocket too big for extractor groove diameter.

 

[Gater]

I am currently working up some loads for 223 rem for a MSR using 60Gn Hornady Vmax and H335 powder. The Hornady manual states the max load is 22.9Gn to give 3000fps. I used 22.5Gn and was running 2550fps in my rifle so I increased to 23.0Gn and am running 2600fps. I saw a load on loaddata.com for 25Gn which they called max and most accurate. My question is should I move on up looking for pressure or cycling issues or call the Hornady max listed as max.

25gr of W-748 will get you over 3000 fps and it flows good through the powder charge

 

[venatic]

Here is me working up 223 with H335 and 55 gr

223 55 gr max published load Hodgdon 25.3 gr H335

unfired, extractor groove .329"
28 gr, extractor groove .329", 11% overload 69 kpsi
29 gr, extractor groove .329", 15% overload 80kpsi
30 gr, extractor groove .3295", 19% overload 92kpsi
31 gr, extractor groove .3320", 23% overload 106kpsi

If you do the same sort of test on other case head designs, a hierarchy contrary to SAAMI registered max average pressure emerges:
1) 6mmBR case head too strong to damage, primer fails as limit
2) 223 case head is very strong
3) Belted magnum case head is strong, but not as strong as 223
4) Mauser case head, 270, 250Sav ect, very strong but not as strong as belted magnum
x) 10mm handgun, 25acp handgun, 30 carbine... very weak case head, primer pocket too big for extractor groove diameter.

Very interesting did you run these loads thru an AR ?

 

[rewiltshire]

I have been told, don't know how true is is but many people have told me this, that the load data in manuals have been cut back a little bit to keep them out of the high range because of the different types/age/condition of firearms. They are not in the business of fighting lawsuits because some idiot with an old beat up unserviceable rifle was loaded to max and blew up.

 

[Clark]

Very interesting did you run these loads thru an AR ?

These were fired in a 1979 Colt SP1 AR-15.

 

[bigedp51]

My Savage bolt action .223 with a 1in9 twist has a longer throat than my AR15 rifles. And can be loaded "warmer" than most manuals.

Most .223 loading data is from shorter throated rifles with 1in14 or 1in12 twist rates.

Below the freebore length (N) and freebore Diameter (G) can effect chamber pressure.

 

[Gater]

These were fired in a 1979 Colt SP1 AR-15.

They lower the loads because Ya can't fix stupid some people want to push the limits and when they hurt them selves they want to blame others unfortunately our courts let it happen