I need a bit of advice…I’m wanting to load the above, But the newer hornady manual shows 23.1 as max…(using a Rem700 and a 26"bbl)A older loadbook that has a section for AR-15 loads(using a Colt with a 20"bbl 1/7 twist) shows h-322 going up to… 24.3 as max…I know you can go a little hotter than 23.1… I was thinking of using 23.3gr, as I’ve done a search and read a few other people using it with good results in their AR’s. This would be used in a AR with a 5.56 chamber (DD barrel) Has anyone use 23.3? Results?
Hodgdons shows 23.1gr as max for a Speer 55gr SP.
Work it up and check for signs of pressure.
Markm works with h322 a lot. Maybe he has some info, most of what I have seen he loads 77 smk with this powder though.
I’ve loaded 55gr to Markm’s 77gr load wich is 21.6 grns with no issues in my DD. Smooth load but cycles fine.
Man… It’s almost a crime to load that good powder with 55 grain bullets… but if that’s all you have in the current market… 
I’ve never tried it with many light bullets. 69s and 77s love it though.
I know what you mean. I had a guilt trip myself loading them. H322 was the only powder I could find at the moment so bought 6# worth and got to it. Btw that 77gr load groups very well thanks.
There’s no price difference… but it’s still a bummer. 
Well, I called Serria (who’s data I was using) and asked them about using 23.3gr H322 and 55gr hornady…and the tech told me he didn’t see a problem with it… and it should be fine… I’m going out and run some over a crono here in a little while…
Markm, I understand what you’re saying about the bullets… unfortunately, these are all I could find,
I hear you… they’re good bullets to have in 55 fmj. No sadness in owning those at all.
Well, I just got back from the range…I’m happy to report there were no problems observed with this load, cases showed no signs of high pressure and everything worked normally.
here’s the numbers from the crono…
1.2862 Lo2773
2.2812 Hi2890
3.2850 Av2838
4.2890 ES 157.3
5.2773 SD49.52
6.2796
7.2864
8.2886
9.2812
10.2871
I did shoot 10rnds at 50yds for accuracy… It wasn’t bad by any means… The rounds were stringing horzionally…due mainly I figure, to winds gusting about 10-15mph plus…one string of five measures 1 3/8" ctr-ctr in length and a 1 1/4 wide ctr-ctr. The other measures 1 7/8" in length and probably 1/2" wide… One thing I did mention to the tech at Serria was the fact that both Hornady and Hogdon both stop at 23.1…His reply was “Yeah, I know, I don’t know why they do that”. The tech also told me to call him back if I had any problems… The rifle I used was a DD with a DD 16" pencil bbl, 1/7 twist.
You know what we just got? Some of this LT32 Benchrest powder. Load min/max look similar to H322. The powder kernels look similar too.
I’m going to sling a few 69 gr SMKs on Friday to get a baseline of the powder.
I have loaded a lot of 55gr FMJBT w/c Hornady bullets using 23.5gr of H322. I have tested CCI #41 primers, Rem 7 1/2 primers, Win SM Rifle and Wolf SRM primers with this load.
The highest velocities were with CCI #41. The smallest ES was with Wolf SRM. No pressure signs with any primer. Velocity with CCI #41 avg=approx 2880fps from 16" BCM 1:7 barrel. Velocity with other primers approx 50-80fps slower.
I found primer seating depth and preload to have a significant effect on ES and SD with all brands of primers. Using my Sinclair tool to seat primers exactly -.003 below the case head reduced ES by about 30% on ten round strings.
When I was doing these tests I was using once fired LC brass matched by weight to ±.5gr. They were trimmed to 1.750 ±.002 and neck expanded with a mandrel to .222 diameter (.002 less than bullet diameter). Bullets were “medium” crimped into the cannalure with a Lee collet die.
The powder makers max loads are usually tested in a min spec 223 chamber - think bolt gun. The extra free bore in a NATO chamber can lower peak pressure by as much as 5000psi so loading manual max loads are very conservative for a NATO chambered AR.
Thanks for mentioning the Sinclair tool. I’ve been wanting to add one to my god tools box for quite a while. The SD dragon is one that is hard to catch but as I get into longer and longer range shooting I am seeing its effect quite prominently at 500+ yards. The old 250 yard being long range is now out the window.
Greg
I’ve loaded Hornady 55s with H322 to match M193 velocity out of my 10.5" Noveske. 23.8gr with a CCI 450 or 41 primer, 2.190" OAL and a light crimp. It’s very accurate for me and I see no signs of high pressure. I could post my chrono results when I get home today if you want it.