It's been pretty hotly contested as to how much diffrence there is between loading 7.62x39 using .308 bullets vs .310-.311 so here it is. I tested this today and here are the results.

The rifle is a CZ527 carbine topped with a 3x9x40 redfield accutrac scope. The bore measures .300 land to land and .3105 in the grooves

The ammo was loaded with 150 gr Sierre soft points 10 rds of .308 and 10 rds of the same bullet sized .311. Cases were Remington CCI 400 , The powder was 23.5grs of Re-7 with a COL of 2.310

It was about 65 degrees today with a light varible breeze of 15 mph

Shot string 1
.308 bullets

1851
1826
1852
1827
1846
***************
Shot string 2
.311 bullets

1935
1904
1937
1912
1925
****************

Shot string 3
.311 bullets

1953
1888 !?
1915
1932
1925
***************

shot string 4
.308 bullets

1852
1855
1869
1844
1873

All velocities were taken at 25 feet.

As you can see there is very little diffrence in group size. About the only real measurable diffrence in using the .308 dia bullets is that they are somewhat slower in the FPS department.

Of course your mileage may vary.

Thanks. That was a good test. I got nearly the same results but perhaps better grouping using IMR 4198 and AA1680 in worked up loads. 1/1000 deeper a groove on each side likely does not affect things much in this cartridge, but it does offer a much wider choice of bullets. There really shouldn't be any fuss over the practice, particularly since bullet diameter is often nominal. Regards, ned.

What does it do with 125 grain bullets? I think that's what the rifle is designed for.

quote:

Originally posted by Bill Mc:
What does it do with 125 grain bullets? I think that's what the rifle is designed for.

I shot some nosler 125gr ballistic tips today they ran about 2370 fps grouping about 1.5 inches
The Barnhual 125gr soft point ammo chronied an even 2500 FPS with about a 2.5" group.
By far the best groups have been with the 154 gr wolf ammo here is a picture of a 3 shot group at 100yds

quote:

Reply

A couple years back I got some of those 125 Barnaul bullets(not cartridges) and they gave the best groups by a fraction of any common .308 diameter 110, 125, 135, 150 grain American bullets I could get. I was using a Sako L461 actioned rifle with a .308 though. But the Barnaul miked out at .310.

Krochus welcome to AR, Many thanks for the information and keep up the good work. The little .30 is a great favorite of mine, and has taken some wonderful trophies for me. The Mountain Lion avatar is just one of them. By all means try the AA1680 powder and the Norma factory ammo is nice and hot also. Good shooting.



Dave

I can't believe that your gun will shoot wolf like that, are you sure it wasn't luck I have a CZ varmint that will do a 5 shot MOA with about 7 types of factory stuff, but wolf and milsurp m855 ball ammo, patterns with groups of around 3-4"

quote:

Originally posted by cummins cowboy:
I can't believe that your gun will shoot wolf like that, are you sure it wasn't luck I have a CZ varmint that will do a 5 shot MOA with about 7 types of factory stuff, but wolf and milsurp m855 ball ammo, patterns with groups of around 3-4"

Every time I shoot this ammo I usually manage to squeeze out at least one sub MOA group with the one pictured being the best. Just because your rifle will not shoot the stuff does not mean that my rifle in a completely diffrent caliber won't

quote:

Originally posted by Krochus:

quote:

Originally posted by cummins cowboy:
I can't believe that your gun will shoot wolf like that, are you sure it wasn't luck I have a CZ varmint that will do a 5 shot MOA with about 7 types of factory stuff, but wolf and milsurp m855 ball ammo, patterns with groups of around 3-4"

Every time I shoot this ammo I usually manage to squeeze out at least one sub MOA group with the one pictured being the best. Just because your rifle will not shoot the stuff does not mean that my rifle in a completely diffrent caliber won't

I was just messin with ya see my Those CZ carbines are neat guns I have one in 223.