05-19-2011, 03:30 AM
stanc,
I suspect something like a 6.5x47 Lapua on full auto would be a barrel burner, but that is the direction the performance objectives would most likely lead. If a Grendel could match 7.62 M80 out to distance, that would be great, but getting the projectiles to speed is the problem. I'm just anticipating those that will say that they have a certain perceived or real performance of M80 ball at 700m, 800m, 900m, that the Grendel clearly does not, as far as hard impact on target goes.
If the requirements were reduced to say that it equals 7.62 trajectory only, then there is probably some room past 600m to argue in favor of the 147 impacting certain targets vs. an undetermined mass-produced 6.5 round of lesser weight. That's why the 140gr 6.5 military bullets interest me. I would not want the x55 case length for the reasons stated previously.
It is interesting to note that the 6.5x55 Swede with 140gr Norma Spitzer probably weighs less than the 7.62x51 M80 with 147gr, given the differences in case dimensions. The Norma might have a lesser powder charge weight as well, since it doesn't take as much to get a 140gr going 2600fps from a tighter neck when compared with what it does to get a 147gr going over 2800fps, and the Swede needs a slower-burning powder to push that bullet with its long bearing surface.
LRRPF52
I suspect something like a 6.5x47 Lapua on full auto would be a barrel burner, but that is the direction the performance objectives would most likely lead. If a Grendel could match 7.62 M80 out to distance, that would be great, but getting the projectiles to speed is the problem. I'm just anticipating those that will say that they have a certain perceived or real performance of M80 ball at 700m, 800m, 900m, that the Grendel clearly does not, as far as hard impact on target goes.
If the requirements were reduced to say that it equals 7.62 trajectory only, then there is probably some room past 600m to argue in favor of the 147 impacting certain targets vs. an undetermined mass-produced 6.5 round of lesser weight. That's why the 140gr 6.5 military bullets interest me. I would not want the x55 case length for the reasons stated previously.
It is interesting to note that the 6.5x55 Swede with 140gr Norma Spitzer probably weighs less than the 7.62x51 M80 with 147gr, given the differences in case dimensions. The Norma might have a lesser powder charge weight as well, since it doesn't take as much to get a 140gr going 2600fps from a tighter neck when compared with what it does to get a 147gr going over 2800fps, and the Swede needs a slower-burning powder to push that bullet with its long bearing surface.
LRRPF52