Home Forums Hunting & Shooting Hunting Rifles Velocity change in older ammo (1000+ fps!)

Hey everyone. I purchased some Remington "Premier Partition" ammo (210gr NP) for my .338 Win Mag back in 2002 or so. I never really watched how it was stored - kept it in the box in my basement (dry) and then upstairs for 5 years or so.

Well, decided to go to the range today to shoot a rifle that I had done some work on (bedded, shortened the barrel to 22", new stock). Put 7 rounds down the pipe. I was shooting over a CE ProChrono Digital. These factory loads were advertised at 2800+fps muzzle. I couldn't believe it when the FASTEST of the seven flew at 1860fps (chrony centered 10' from muzzle). 1000fps slower than advertised... Accuracy was fine and the speeds were consistent.

What are your thoughts on this? Is the powder a slow burner that is *that* affected by the short barrel? Old ammo has just slowed down? Never was fast in the first place (never checked it)? It did have decent muzzle blast.

I have some new factory loads (Fed 250gr NP) that I shot today also. They avg'd 2963fps out of the same gun. Hmm.

how was the recoil?

You bought the ammo new from a store??

Stores have ammo?

I can't remember this morning.....much less way back to 2002.

The recoil was as sharp as it always was. Honestly, I didn't feel much difference between the slow 210s and the fast 250s...

Yes, I bought the ammo new. I bought 5 boxes (all same lot) from Cabelas. Luckily I don't have much of it left. I will probably take it apart for reloads.

I'd get a 2nd check on the chrono before you break that ammo down..........in that period it shouldn't have deteriorated that much unless they were subjected to some pretty warm temps for a sustained period of time.

MM

How about 2963 with 250? That is even more amazing.

Think it might have been 2693.

I'm thinking chronograph issues.

OK, went and got my chrony so I could give exact numbers. I was off a bit. The slowest was 1860 on the 210s. My memory sucks I guess. Or, maybe my .338WM knocked me around a bit.

The 210s were: 1940, 1940, 1966, 1885, 1919, 1893, 1860
The 250s were: 2732, 2763, 2763, 2741, 2749, 2755

130gr ABs out of my .264 Win Mag were: 2943, 2936, 2917, 2915, 2942, 2925. Ive chrono'd these loads off of another chrony any they are consistent w mine.

OK, so the speed was a great deal slower, but what was different about the direction in which the bullets traveled?

Um, not sure what to say about that 5sdad. They all traveled north, lol.

If recoil was the same, speed was close to the same. you got chronograph issues, not ammo issues.

My chronograph claimed 7000fps+ once. It needed a new battery.

I will shoot 5 of them over my dad's chrony to see if mine isn't correct. From what I've seen so far, I trust it (mine).

Velocity involves speed and direction.

If I had to guess, the muzzle blast in that particularly load is triggering the start sensor because it can reach the first sensor before the bullet (especially with the start sensor only 10' away). Than when the bullet triggers the stop sensor it results in a longer time between when the start screen is triggered by the muzzle blast and the bullet triggers the stop sensor.

For the the other loads that clock with reasonable velocities, there may be a difference with the muzzle blast, etc.

I've seen the same thing particularly with loads that have a pretty severe muzzle blast. Try moving the sky screens farther away from the muzzle. I doubt that the muzzle blast actually dropped 700+ fps especially if the ammo was stored in reasonable conditions (i.e., temperature, humidity, etc.)

210's at 1800 would've recoiled like a .243.

Thanks for the ideas guys. I will move the chrony out AND try another. All good ideas.

+1

2963 would probably cause some serious problems. As some of the guys said, the chrony is probably faulty.