There seems to be quite a discrepancy as to the max load of H335 with 55 grain bullets. They list max load at 23.2 H335 for 55 gr bullets, my lyman lists a higher max load. I have been loading 24.9 of H335 with no problems and no signs of excess pressure. Which book appears to be right ?
Also the new Hornady lists 5.56 but has very few bullets listed.
It also says the 223 is a shorter chamber than the 5.56 so do we use the case COL in the 223 lists or in the 5.56 lists since most AR15 barrels are chambered 5.56 ?

Rebs, you load to magazine length, also the charge discrepancy is because the leade or throat of the 5.56 chamber is so much longer than the one on a .223 that when we shoot a bullet loaded to .223 specs we get a major pressure drop. In my testing my most accurate bullets were higher than what the books or even Hodgdon showed. I figured I was wrong. Now comes the new Hornady and my loads are within what they show for a 5.56. Now I feel comfortable loading those loads, which has prompted me to pull another 250 rounds and load them to what I found to be accurate and not the max of what the .223 was. I do not use the GMX but I use a lot of other Hornady 55gr rounds and my most accurate load is .1gr under what they show for max. My 68gr BTHP Matches are at the bottom of the load range and they are not my most accurate loads as are my 75gr Amax, I cannot wait to add 1.5gr to those loads.

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Grover Oathkeeper