British Motorcycle Gear

Categories: Guns

Stupid Hot 7.62x54R Ammo

When good buddy Jim and I became interested in Mosin-Nagant rifles about 10 years ago, we bought a few boxes of PRVI-Partizan 7.62x54R ammunition mostly to get the brass so we could reload it.  Boy, oh boy, that stuff was stupid hot.

A 91/30 Mosin-Nagant rifle. These are awesome firearms. They used to be plentiful and inexpensive. Now they are neither.

We could feel it in the recoil and the pressure pulse of each shot.  After a few rounds we called it quits.  I didn’t want to fire any more through my Mosin and neither did Jim.  The primers were sharply flattened, the bolts were hard to open, and the brand-new cartridge cases were fracturing.

A fractured case mouth in a factory round that was clearly loaded way too hot.
You think this might be a sign of excess pressure?

We only fired two or three rounds from each box, but that was enough.  Prior to that point, Jim and I had fired only our reloads, and those were about in the middle of what the Hornady manual recommended.  The PRVI-Partizan ammo was way hotter than our reloads.

When we returned home, I grabbed RCBS inertial bullet puller and pulled the bullet out of one of the cartridges.

An RCBS inertial bullet puller.
You put the loaded cartridge in the end, tighten the cap, and whack the other end on a hard surface a few times. Inertia drives the bullet out.

I thought maybe the bullets were slightly oversize and that was causing an overpressure condition.  But they weren’t.  They miked in at 0.312 inches (right where they were supposed to be).

Bullet diameter: Check!

I dumped the powder from the cartridge case and it weighed 52.7 grains.  I had no idea what the powder was, but the powders I had loaded 7.62x54R ammo with in the past (primarily IMR 4320) had always been at 43.0 to 43.7 grains.  My reloads were hard-hitting and accurate, and they felt about right to me.  They recoiled and had a muzzle blast roughly comparable to a .308 Winchester, which is about what the 7.62x54R Russian cartridge is ballistically equivalent to.  I didn’t see any powders in my reloading manual that went north of 50.0 grains.  Nope, this PRVI ammo was just way too hot.  Stupid hot.

The PRVI-Partizan propellant was a stick powder, but I had no idea what it was. I just know they loaded too much of it.
My RCBS powder scale. I’m old school.
52.7 grains of whatever it was. And it was stupid hot!

I pulled the rest bullets with the RCBS inertial puller, dumped all the PRVI propellant (whatever it was) in my RCBS powder dispenser, and reloaded them with the original PRVI bullets, brass, and primers with a dispensed charge of 44.0 grains.

I reloaded the disassembled ammo with 44.0 grains of the mystery PRVI propellant.

I wasn’t trying to be too cute or too scientific; I just wanted something that filled the case to about the same level as my IMR 4320 load.  I didn’t have more of the PRVI propellant, so I wasn’t seeking the most accurate load.  Jim and I had only bought the ammo because we wanted the brass.  We just wanted to shoot it up without blowing up our rifles.

My reloaded new ammo.

That revised PRVI load worked well.  It fired, it expanded the brass to obturate adequately, and I now had once-fired PRVI brass in good shape.  The revised PRVI load was reasonably accurate enough, too.  I think somebody at the PRVI ammo factory just wasn’t paying attention.

These guys were oblivious to what was going on around them. They could have been workers at the PRVI ammo factory.

The next day when Jim and I were on the range, a funny thing happened:  A small group of deer wandered out in front of us, oblivious to our presence and the fact that they made an easy target.  But it wasn’t deer season, were didn’t have our licenses with us, they were the wrong sex, and bagging one could result in a $40,000 fine here in California.  Jim and I sat quietly, and the deer walked to within 30 feet of us.


More Tales of the Gun!


Never miss an ExNotes blog:

Joe Berk

Recent Posts

ExNotes Review: UABRLA Tire Inflator

By Joe Gresh There's a reason we call this pump a tire inflator instead of…

1 day ago

World War II Harleys

By Joe Berk Harley-Davidson built four military motorcycles during World War II: The WLA, the…

5 days ago

ExNotes Long Term Test: Oxilam LED Headlight Bulb

By Joe Gresh As you'll recall from the Oxilam headlight review we published on ExhaustNotes…

1 week ago

Shinya Kimura at the Harley Museum

By Joe Berk Astute readers will remember our post on Shinya Kimura, an artist who…

2 weeks ago

Krabi, Thailand

By Mike Huber After 5 weeks on Koh Tao it was time to move on…

2 weeks ago

A Stag Film?

By Joe Berk For a guy who doesn’t collect knives, I sure seem to have…

2 weeks ago