H322 and 5.56

[N555]

I had a few pounds left over from the 1990s that I was going to use up, then I bought some more at a garage sale.
https://www.thehighroad.org/index.php?threads/223-55gr-fmjbt-h322-16-5-bbl-and-a-chronograph.516652/
I found the same thing when using H322 in 30-30, around the start load accuracy was good/acceptable, then get near the max and you are lucky to be shooting 4moa.
I loaded up 7 of each, M193, H322, cci non magnum small rifle primer, book coal, LC brass. At 22gr 22.5gr and 23gr.
In speer 12 the start load is 22.5 and the max load is 24.5.
In Hornady 9 the start load is 19.5 max 23gr.
I loaded up 1 at 20gr fired it over the chronograph, it errored and it made a nice yellow fireball out the silencer on a 20'' barrel, tells me 20gr is too light and I'm not getting consistent quick powder burn.

 

[N555]

What was not clear now is.
Hornady 9 start load of 19.5gr probably won't reliably cycle a semiauto.
Today had like 40mph winds so I went to the indoor range and picked up like four hundred 223 and 9mm, so it was worth it.
If I couldn't tell the difference between groups at 25 yards I would move it outside whenever the wind was good and I had a day off.
The seven M193s I loaded over 22gr seemed to be soft shooting, didn't lock the bolt back after the last shot, with a silencer on 16 inch 1:7 twist delton barrel. Don't know if it was a fluke or what. 20gr of H322 locked the bolt back the other day when the gun was nice and clean. Maybe more than meets the eye at work. 22gr shot 1 inch by 1 inch edge to bullet hole edge or about 3/4 of an inch.
22.5gr of H322 made almost a 1 hole group of 7 at 25 yards. 11/16 tall minus -0.22 is less than a half inch. That is acceptable. Windage was about 3/8 center to center.
23gr of H322 was about like 22gr, a 1 inch by 1 inch or about a 3/4 inch group center to center. 23gr of h322 gave no indication of high pressure. As 23gr is max load for Hornady9 and a full grain under max in speer13.
In speer13 the start load of H322 is 22.5gr, looks like speer knew what they were talking about.

 

[kalielkslayer]

I AM NOT A .223 EXPERT but 24 grains does it well with most powders.

Not pushing limits but both A2230 for light bullets and TAC for heavier bullets like 24 grains.

Just my personal opinion!

 

[IALoder]

My experience with H322 in .223 was very similar, albeit with 62 fmjs. Didn't consistently function in my AR's till about 22.5gr, shot great at 23.0, and started getting light case swipes at 23.5. All loads were very soft shooting, just a little slower on velocity than I'm used to with the 62fmj. Loaded what was left of my lb at 23.0, and it has been a pretty solid load! H322 is a little bit too fast burning for what I like to do in .223, but I bet it's awesome with 40 through 55gr!

 

[N555]

Shot some over the chronograph out of my 1:7 twist 16.5 inch midlength.
Got 2,690fps. So it will keel.
What it lacks in raw power it makes up for in accuracy.
I also have a DSC 1:9 twist 16.5 inch heavy carbinelength upper. Got 2,795fps out of it.

 

[N555]

I fired some in the rifle with out silencer, they didn't cycle. Ejected but failed to load the next shot.
Now if you had like a carbine buffer, maybe.

 

[doubleh]

I love H322 in 223. It is very accurate. I find that it is most accurate at less than max loads.

 

[N555]

H322 vs ballpowder
Ballpowder burns so dirty.

 

[IALoder]

Just looked at my Chrono data, in a 16" CHF/CL barrel 23.0 H322 gave me 2795 fps with a Hornady 62 fmj at 88°. I can't find my Chrono data, but I'm pretty sure the same load was around 2750 at 25°. Cycles even when dirty, very soft shooting.

 

[scott511]

I love H322 in 223. It is very accurate. I find that it is most accurate at less than max loads.

Same here. About a grain short of max gives me excellent results in 3 different rifles

 

[N555]

Midlength 16 inch Delton barrel with silencer with an "H" 3.8oz equivalent silent buffer is still way over gassed.
Picture poached from here:
https://www.80percentarms.com/blog/ar15-buffer-weights-what-the-difference-is-and-how-to-choose/
Ejecting 45ish degrees forward.

I'll pop in the "H2" 4.7oz twang buffer and retest.

 

[N555]

Tossed in the 4.7oz "H2" buffer. Better. Recoil was like shooting a 22wmr.

If I dig into my junk collection I think I have a twang style H buffer. I can poach the tungsten from my H and H2 buffers and make an H3 twang buffer.

 

[N555]

5.6oz H3 buffer installed and tested.
Pretty darn close. I can further test with my collection of various springs.

 

[N555]

I made a 7oz H5 carbine buffer, which is a steel body buffer with 3 tungsten weights in it. Gave pretty much the same results as the H3 buffer.
Time to add the adjustable gas block.