ballistic problem, who can help me?

[artemistrad]

I have caliber 5,6x50Rmag. This is almost identical to .223. But then with a little more casevolume. Actually the casevolume is 33,9grain H2O.
So I tried different loads from 24 till 28gr of Benchmark behind a 50grain TTSX bullet. I tried different bulletjump from 0.02 till 0.5. Till now the 27gr load is best but not good enough jet. As it has 3" groups at 100m. Don't know what goes wrong here. Is the powder to fast? With this same powder, same gun and 50gr V-max bullet I have 0,5" groups. Wo can clear me up? Thanks! Mark

 

[kimba]

well more bearing on the all copper bullet and longer tsx? might it req more jump than the vmax? what does your chrono tell you re speed es and sd? unless wanting a deer round the vmax will almost always be more accurate - try the 52 amax for most accurate. I like the 60 partition better for deer and antelope and it shoots fine in 223. Use the chrono to look at speed peaks as well. I would wonder if longer bullet and more bearing on tsx might change pressures and accuracy nodes. I have heard the all coppers need a really clean barrel - is it pristine?
twiste and barrel length?

 

[Bill Johnson]

might it req more jump than the vmax? ........... I would wonder if longer bullet and more bearing on tsx might change pressures and accuracy nodes.

Barnes suggests starting at .050" off the lands. I'm thinking like kimba, it might like more.

I'd probably increase seating depth in .020 increments up to .100 jump and see if you find a area that bullet likes.