Surplus 150 FMJ machine gun projectiles purposely poor precision? Or 'how to prank a fellow shooter'

[clearwater]

Were military bullets for machine guns purposely made to scatter like a shotgun when fired?

Grandpa has a National Match Garand he used to compete with. Thought I would make him some ammo as close to WW2 as I could. Washed, reamed the primer pockets, and tumbled some LC 43 brass, found a Garand recipe with IMR 4895 and some 150 FMJ surplus bullets. The bullets looked like new, shiny copper like made yesterday. Went to the range and shot a few thru Grandpa's stock out of the cosmoline 03-A3. At 50 yards I had 10" groups? I thought, boy I am terrible with open sites these days.

Went back to the range with Grandpa's sportered 06 with a nice leupy 10 power scope.

again terrible groups

Then tried it in my old faithful and still some shots off paper.
At this point I blame the bullets.

If i were a cruel man I would let grandpa unknowingly shoot them.... Maybe keep a few good loads in my pocket and show him how its done!

They were his projectiles, and when asked he said, "Oh those were machine gun bullets that came very cheap. Likely made that way on purpose to scatter"

So is that a thing? Or were they just culls? How would one discover they are bad? The weights are consistent.

 

[truck driver]

From my experience with military machine guns( M60 ) I have found them to be very accurate, to the point that some had been fitted with rifle scopes for long range sniping.
I was known to use the one I carried to clear firing lanes including cutting down medium-size trees like a chain saw.
I think you picked up some factories reject bullets, not simple blemished bullets.

 

[PJGunner]

I remember reading about something about that but id was for .50 Caliber ammo to be used in fighter aircraft to help insure more hits on enemy fighters etc. I think there must be some truth to this, especially in WW2 where some films like Flying Leathernecks used actual combat footage. AS hey strafe an enemy ship, bullet strikes were all over hell and gone around the target.
I never heard of this being done with .30 caliber though. They just could be some WW2 bullets that were a bit sloppy in manufacture. I know that I never did get really good accuracy from the ones I pulled from WRA42 and LC43 milsurp ammo. At least the brass was good once I deprimed those corrosive primers and reamed out the ring on the primer pockets.
PJ

 

[RossRR]

I remember reading about something about that but id was for .50 Caliber ammo to be used in fighter aircraft to help insure more hits on enemy fighters etc. I think there must be some truth to this, especially in WW2 where some films like Flying Leathernecks used actual combat footage. AS hey strafe an enemy ship, bullet strikes were all over hell and gone around the target.
I never heard of this being done with .30 caliber though. They just could be some WW2 bullets that were a bit sloppy in manufacture. I know that I never did get really good accuracy from the ones I pulled from WRA42 and LC43 milsurp ammo. At least the brass was good once I deprimed those corrosive primers and reamed out the ring on the primer pockets.
PJ

I would expect bullets coming from an aircraft moving at 200-400 mph, and often being shot while the aircraft is maneuvering, to have some variability in flight path. I'm not sure the variability we observe in those films were due to bullet manufacturing practice, but I guess it is possible.

 

[GregoryB.]

Spent the first 11 years of my 26 year Military career humping some kind of machine gun. Zeroed enough on them to know the ammo was accurate even with night vision scopes.