I'm finally loading a few rounds to test for velocity and pressure.
The guy at Nosler told me to use the 5.56 NATO data, since .223 Rem didn't include the bigger bullets. DISCLAIMER: the book (#7) states "The data listed in this section is safe for use in both .223 Remington and 5.56x45mm cartridges and chambers."
Nosler lists 23.5 gr TAC and 24.0 gr Varget as max, with identical MV of 2658 fps from a 20" barrel. Add 50 fps or so for the difference in barrel length puts me a hair over 2700.
Ramshot lists 24.3 gr of TAC as max with the 80 gr Sierra HPBT, 2749 fps, 24" barrel. Subtract 30 fps puts me close to Nosler's estimate of 2700, at .8 gr less. Ballpark, anyway.
Ramshot's TAC numbers for 5.56x45mm go up to 25.8 gr for 2903 fps, 1-7", 24" barrel. That's more velocity and pressure than I'm looking for.
Hodgdon lists 25.0 gr Varget as max, but that's compressed. 24" barrel, 2869 fps. That's around 2835 fps from my barrel.
I think I'll work up to 24.5 gr Varget and 24.5 gr TAC as max. Now all I need is a scope.
P
