Originally Posted By: Martyn4802Originally Posted By: yoteblasterMartyn you must be looking at the data for the AR-15, that shows a max of 25.7. The data for the bolt guns shows 27.5.
The edition of the Sierra Loading Manual I have is the 50th Anniversary Edition. In the section, "Rifle Reloading Data, 223 Remington, 55 grain Bullets", the max load of H-335 is shown as 25.7 graions. No distinction is made in my edition between Bolt and AR-15 for powder charges.
Edit to add: That's on page 210.
Also, 27.5 grains of H-335 with 40 grain bullets in my 223 is max, based on my testing.
I don't know what your source for Sierra load data is.
Marty,
Your manual may be newer than mine?
My Sierra Manual is the 5th edition (Copyright 2003 by Sierra Bullets) which has AR15 load data on pages 213 to 222, and shows the 55g max for H335 as 25.7g on page 218.
In the bolt gun section of the exact same manual, pages 223 to 232, it shows the 55g max load for H335 as 27.5g on page 228.
So now you know where we got that data.
I can say that looking at both loads in QuickLoad, 25.7 @ 3138 & 48,000 psi looks more reasonable than 27.5 @ 3.350 fps & 60,000 psi (5,000 psi over SAAMI maximum even with the increased case volume from using water grain measurements). As others have said, 27.5 is one smoking hot load. That may be why, if your manual is newer than mine, the higher loads have gone away.
Fitch