Weird Eley Match Lot#

[drglock]

Put a new CZ457 together with a Brux barrel and MDT chassis. Been going through different ammo to get a feel for what it liked. It seems to really like the Eley Match so I ordered 8 lots. All of them overall shot really good but found one lot that shot exceptionally well with a velocity range I liked with low SD’s.
So I ordered 3000 of said lot and when it comes in I go to shooting it. Shoots really well but here’s the odd part. It’s actually two different lots. The lot I tested and part of the lot I ordered match up perfectly. Average velocity of 1091fps and SD 4-5. The second lot within this lot has an average velocity of 1111fps with an SD of 6. So far I’ve tested 18 boxes and they two lots are about 50/50. You can test a box and the whole box will be one or the other with SD’s being right at what I posted above. I’ve been in the competitive 22 for a long time and I’ve seen a lot of things but never anything like this. Not going to be that big of a deal but will have to go through every box and chrono and mark that box as one or the either.

 

[Franko]

You are a bit more easygoing than I am. If this happened to my ammo that I was paying $20 a box for I'd be on the phone demanding a whole new batch from Eley. If I'm paying that much I expect it to be as perfect as it can get and hassle free.

 

[tomme boy]

Yah I would be sending that crap back

 

[justin amateur]

Same lot number?
20 fps difference in average velocity? 1.8% of MV?
At 50 yards the difference in poi would be about 0.14 inch of vertical.
Edge of a 22 would still score the 10, right?

I'd be happy to find a lot that had that small a variation in mv's.
Unless it's spitting odd strays due to other cartridge issues.

 

[drglock]

Edge of a 22 would still score the 10, right?

What’s this 10 you speak. Must be a game for more civilized people. No 10 to hit the edge of in PRS22

 

[drglock]

Same lot number?

Yes all the same lot number on the boxes

 

[justin amateur]

The velocity differences aren't a surprise.
When the factory labeling process is based on statical sampling,
management establishes acceptable defect rates,
defect levels, level of confidence to be applied to establish the sample size.
Profit is job one, expense kept to a minimum,
so 400 shots are all that are actually fired to label a batch of 28,000 cartridges.
That leaves room for less than stellar quality product to slip by.

Welcome to the assembly line lottery.
We pays our money, we takes our chances.

 

[drglock]

The velocity differences aren't a surprise.
When the factory labeling process is based on statical sampling,
management establishes acceptable defect rates,
defect levels, level of confidence to be applied to establish the sample size.
Profit is job one, expense kept to a minimum,
so 400 shots are all that are actually fired to label a batch of 28,000 cartridges.
That leaves room for less than stellar quality product to slip by.

Welcome to the assembly line lottery.
We pays our money, we takes our chances.

Yes but you would think that it would be all mixed in on the boxes not whole boxes with identical different lots. It’s almost like two different lots got mixed after they were boxed but before being labeled

 

[grauhanen]

So I ordered 3000 of said lot and when it comes in I go to shooting it. Shoots really well but here’s the odd part. It’s actually two different lots. The lot I tested and part of the lot I ordered match up perfectly. Average velocity of 1091fps and SD 4-5. The second lot within this lot has an average velocity of 1111fps with an SD of 6. So far I’ve tested 18 boxes and they two lots are about 50/50. You can test a box and the whole box will be one or the other with SD’s being right at what I posted above.

Six bricks of one lot of Eley Match were ordered. All bricks/boxes have the same lot number. Eighteen boxes of this ammo have been tested, and half of the boxes have an average MV of 1091 fps with SDs in the 4 - 5 range. The other nine boxes have an average MV of 1111 fps (20 fps higher), with SD of 6.

The hypothesis is that this ammo is actually two different lots of Eley Match that somehow have the same lot number.

If the above is correctly summarized, in the absence of further information there may be a possible explanation.

The obvious one is that the testing was done on different days when temperatures were different. If one day was much warmer the higher temps would cause the ammo to have higher MVs. Of course if the testing was done with very similar temperatures, this explanation is not valid.

The different SD values themselves, however, should not be surprising. Different boxes of ammo from the same lot can easily have different SD values, even when tested at the same temperature.

 

[whatsupdoc]

LOL 20 FPS variance in 22 rimfire ammo and you think that its two lots.


How many shots in the sample size in your test?

 

[drglock]

The obvious one is that the testing was done on different days when temperatures were different. If one day was much warmer the higher temps would cause the ammo to have higher MVs.

My testing was done on the same day and actually within two hours from start to finish with maybe a temp change of 5 degrees. Shot from inside my garage with the gun or the ammo never being in the sun. All shots recorded with a Garmin

 

[drglock]

LOL 20 FPS variance in 22 rimfire ammo and you think that its two lots.


How many shots in the sample size in your test?

Whole boxes until I realized what was going on. Yes I’ve had Center X before that had a ES of 50. Each and every box I tested has had very good SD’s for 22 ammo. I’ve got 4 unopened bricks that i guarantee you you can open and randomly select 4 boxes and test them and the boxes will be one of those average velocities and out of the four selected there will be at least one if not two that’ll be the other velocity

 

[grauhanen]

My testing was done on the same day and actually within two hours from start to finish with maybe a temp change of 5 degrees. Shot from inside my garage with the gun or the ammo never being in the sun. All shots recorded with a Garmin

The first post indicates eighteen boxes were tested, with half of them having the 20 fps difference. If all were shot within two hours, that would be 900 rounds within 120 minutes. A brisk pace, perhaps, but it wouldn't account for a distinct MV difference between half the boxes shot, which remains the mystery.

An SD of 4 for .22LR match ammo would be exceptionally low over 50 rounds. An SD of 5 is low for match ammo. Any SD/box that are 6 or 7 will from the same lot should not be considered unusual.

 

[drglock]

If all were shot within two hours, that would be 900 rounds within 120 minutes.

No where did I say I shot 900 rounds. That would be ridiculous and wasteful just to figure out what I did.

 

[grauhanen]

No where did I say I shot 900 rounds. That would be ridiculous and wasteful just to figure out what I did.

So far I’ve tested 18 boxes and they two lots are about 50/50.

Eighteen boxes of 50 rounds is 900. If I've misunderstood what you meant I apologize.

 

[drglock]

Eighteen boxes of 50 rounds is 900. If I've misunderstood what you meant I apologize.

Yes I meant 50% on the different velocity and yes I tested 18 boxes but only shot 4 full boxes. Didn’t want to shoot them all up just to prove the point to myself. Shot 20 rds out a few boxes then just switched to picking a random five out of a box. Then marking each box accordingly. Sorry my Oklahoma red neck might not of stated it right.

Pulled another brick this morning and did the five out of each box and separated the boxes accordingly.

I truly think it’s two separate lots that some how got combined(whole boxes) before they were labeled. Either by accident or too finish out a pallet

 

[tomme boy]

Any of you guys work in a production environment? Just because it is the same lot # means nothing if the run was started on one shift and ended with another. Nothing is done exactly the same when you have different people making the same thing. One guy will let something run on the high end of spec and the next guy will be on the low end.

I worked in a forging company and watched really good tight tolerance parts being made. Then the next shift comes in and it is a mess what they ran. Then the plant manager comes by and overrides a qc hold because he hopes the bad parts will not be caught at the company we sent them to.