223 vs 556 load data per Hornady

[Rgarbarino]

Question.

I've loaded 223 brass with 55gr Vmax bullets and H322 powder for my target/precision upper. I recently built another upper for plinking that's chambered in 556 and I have 2000 Hornady 55gr FMJ bullets. The Hornady manual doesn't list 55gr FMJ bullets on the page with 556 data.

Would I be ok using the same powder load I use in 223 brass and Vmax bullets in the 556 brass with 55gr FMJs? I do know the COL is different between the two bullets.

Thanks in advance.

[rsrocket1]

The Vmax's are longer so putting a shorter bullet into the same load with a corresponding change in COL should give you close to the same velocities. If you are safely below the max pressure rating of the load, the same charge is safe although it may not be as accurate unless you're real lucky.

You could probably squeeze 1-1.5" difference (2-1/2" down to 1") in your groups at 100 yards if you develop the right load even with a plinker. If it's just for busting soda cans or breaking clay pigeons against a berm, as long as your loads are safe, you're GTG.

Even though many say 55g fmjbt's aren't any better than 2 MOA, I've found that you can get into the low 1's pretty easily without wasting too many bullet in testing. For me, testing is shooting and all shooting is fun.

[Rgarbarino]

Thanks. Thats about what I figured. My target upper is a 24" WOA barrel with 1:12 twist and I can easily get 1MOA with the 55gr Vmax.

The new upper is a 16" Wilson Arms 1:9 twist just for blasting, I'm not so concerned with extreme accuracy. I guess I'll try a couple different loads just to nail down the best I can.