Max Load: H322 in 223 AR


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rfwobbly
December 9, 2013, 10:14 PM
Loaded up some 223 plinking rounds last night and consulted the Sierra manual for 55grn with H322 in an AR. Sierra gave 24.3 as max at 2.250" (3000fps). My load of 23.5grn at 2.250" should have put me right under 2900fps for good accuracy.

Afterward I consulted Hodgdon which gave 23.0 as max for H322 at 2.200" (3100fps).

► Can't believe .050" makes that much difference.

► Going to put some over the chrono and see who to believe.


Any guesses on what the findings will be ?

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rcmodel
December 9, 2013, 10:23 PM
No.

Two totally different test barrels, seated two different lengths.

And I didn't check, but I doubt the brass and primers were even the same brands??
Were they?

rc

Walkalong
December 9, 2013, 10:35 PM
LC brass (91 to 93 Grs), Honady 55 Gr V Max, OAL 2.230 to 2.235, CCI # 41 primer. 16" AR.

24.0 Grs H322 gave an Avg 2943 FPS @ 88 degrees.

24.2 Grs H322 gave an Avg 2954 FPS @ 96 degrees.

24.4 Grs H322 gave an Avg 2983 FPS @ 96 degrees.

24.7 Grs H322 gave an Avg 3041 @ 104 degrees. (3035 @ 102 degrees)

MAX! Approach with caution.

rfwobbly
December 9, 2013, 10:41 PM
Hodgdon used Win cases/ Win pri

Sierra used Fed cases/ Rem pri

I'm using Lake City cases/ Wolf 223 pri

Walkalong
December 9, 2013, 10:43 PM
Can't believe .050" makes that much difference.I can. Looking forward to your results though.

steve4102
December 9, 2013, 10:51 PM
► Can't believe .050" makes that much difference.


It doesn't.

Hodgdon tested in a 24 inch barrel. Sierra tested in a 20 inch barrel. 4 inches of barrel length is the difference!

ngnrd
December 9, 2013, 11:53 PM
What does barrel length have to do with peak chamber pressure?

steve4102
December 10, 2013, 07:21 AM
What does barrel length have to do with peak chamber pressure?

Nothing, why do you ask?

Walkalong
December 10, 2013, 07:33 AM
Bullet construction can make 50 FPS difference, but yea, with a 4" barrel difference, which I did not look at, and assumed it was the same since it wasn't mentioned, all that is out the window.

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