Thread: Best 7.62x39 subsonic loads and tips

The Russians designed this cartridge with a .311 projectile, the Americans use .310 . The 3 Norinco 7.62x39 I have owned bore slug to .3115 to .312. (from new) I have found with the right sized projectile and BH they are capable of extreme accuracy up to around 1700fps.

Originally Posted by KaneB

Thanks for the tip mate, im new to reloading and still yet to test them, could you please explain the benefits of seating the projectiles to the length of the mag vs seating the projectile lower, I also have some high velocity projectiles I plan on loading once I get this rifle sorted so all tips and info are welcome. Thanks

Driverman explained the case for seating bullets pretty damn well from the point of view of dealing with the specifics of 7.62x39.

Here's my 2 cents on the broader reasons for seating bullets mag length, or deeper.

Seating bullets mag length,ie as long as you can reasonably load them, is a safe bet from the point of view of pressure. The deeper you load them, the more pressure generated inside the case. There's a margin where seating them deeper isn't gonna be a problem particularly, so it's not as if it's a no-no.

The other problem is what's called a compressed load. This is where the bullet is seated so deep that it starts to scrunch up the powder in the case.
Sometimes it can be done, sometimes it's a bad idea. It ramps up the pressure inside the case .
ADI loading tables put a "C" beside compressed loads, eg 40.5C (40.5 grains of powder, compressed load)
Too much pressure, and things like primers popping out or being pierced, cases separating inside the rifle,and other unsettling stuff happens.

Trailboss doesn't like being compressed. It may not actually be dangerous ( debatable) but the performance of the loads is said to become erratic.

The other reason for seating at mag length is that the projectile is sitting in the chamber a little bit closer to the rifling than it would be otherwise.
Rifling is composed of lands and grooves.Think of this as being like a rut in a muddy field. The lands are the high edges of the rut , the grooves are the bottom of the rut.

Once it's fired, the lands grip the projectile and spin it, making it stable.

The notion ( as I understand it) is that the shorter the jump for the projectile from the neck of the case to the lands, the better.
I think it helps with bullet stability in flight.

Each rifle has a sweet spot for seating projectiles that it responds to best. Some people swear by seating projectiles long like this, some say that their rifle works better when they do the opposite.

The main thing is not to seat the projectile so deep that there's a kaboom, and your rifle turns into a cloud of flying parts.

There's more to it than this, but that's the short version.

It would be a good idea to google "rifle case overpressure signs" and look at pictures of loads that show danger signs. I generally look at my cases when I've fired them to see if there are any indicators.

some cartridges...the .308 winchester for one... were designed in such a way that it is better to seat the buller really well in the case so it can line itself up with aid of case neck before it makes a "space walk" into the beginning of the rifling.
my norinco loves those 151s and havent seen leading as an issue...yes the cleaning patches come out black...but not a major issue.

bottom line is experiment and FIND OUT WHAT YOUR RIFLE prefers.....

The black stuff is only carbon and bullet lube, if the lube runs out before the projectile leaves the barrel you will get leading, check the muzzle
it should have a star shaped deposit of lube if so the lube is working properly, lead fouling starts out with little flakes of lead that get bigger
if not cleaned out with solvent soaked patches it ends up as long streaks of lead which are bastards to clean out

Originally Posted by scotty

hey, as you have made your own stock the first thing i would do is bed the action....then check the rings and bases .....then the scope .....eliminate all of that then try a few diffrent breeds of ammo my bushranger likes the barnaul 123gr better than the ppu .....once you know it shoots straight then look at reloads as at least then you will have a benchmark to start from.

Hi, I’ve had the exact same results with a Ruger ranch rifle. PPU shoots rubbish. Barnaul shoots 100m around 1.5-2” groups. I found out why. PPU projectile was a tad over .308 diameter. Barnaul .310”. PPU is only good for gathering brass (in my gun)

I’m going to develop a sub load using 180 grain boat tails (.310”) not .308.
I’m going to use AR2207 start at 14grains. Work down to 12 and then 10 and finally 8grains. Hopefully I can borrow a crony and stop when 1000-1100 FPS. I’m thinking that 10 grains will do it. But afraid of getting a stuck projectile. Better to start high and work down.
Cheers