Here's an informative article on loading .223 Rem that shows various case brand weights and internal volumes.
http://www.6mmbr.com/223Rem.html
Here's one range trip chronographing H335 in a Colt AR 20" barrel 1/7 twist. Tested in July with 90degree temperature.
Cases used were RP and WCC using RP 7 1/2 primers and Hornady 55fmj's
RP CASE versus WCC CASE
23.2 grains of H335--2863fps 23.2---2846fps
24------------------2975 24-----3005
24.5----------------3080
25.3----------------3162 25.3--3200fps
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Winchester 55 fmj
RP case--24.5 H335---2979fps
WCC case--24.5------2977fps
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Hornady 55 gr SP
RP case--23.2---2845fps
WCC-----23.2---2829
RP-------24-----2960
WCC-----24-----2969
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62 gr fmj military surplus
RP case--24 grains of H335---2949fps
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Sierra 5th Edition Manual with their 55fmj bullet and H335 tested in an AR with 1/7 twist 20"
23.6--2700fps 24.3--2800 25--2900 max 25.7--3000
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Hornady 7th edition manual used a Rem 700 bolt action 26" barrel with Win cases and Win primers and Horn. 55fmj's
They showed 20.8--2800fps 21.6--2900 22.4--3000 max 23.2--3100
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Hornady also showed a max charge of H335 with their 68gr bthp that was 23.8 grains max at 2700fps. This was shot in an AR
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Just to add to the equation and confusion. use at your own risk.