Case life, and sundry matters appertaining to performance:

[meles meles]

Slightly off on a tangent, or perhaps not, we once had a 7.92x57 case that had a split in it after ejection. It was a milsurp round, one from a batch of 400, and the only one to show a problem. The split was about 3 mm long and halfway down the cartridge. We didn't notice anything unusual on firing, no inaccuracy, no odd sound, no venting of gas. We didn't know anything about it until clearing up the fired brass and finding the split case. The round was from 1953, the rifle a K98. We've seen nothing similar, before or since.

Worthy of investigation ? Related in any way to our question ?

[meles meles]

While they are on they could also figure out why my 45ACP cases get shorter with firing.

Do they?

What evidence do you have?

Is it all cases, or just some?

In what gun ?

*curious*

[meles meles]

We've got a task for you, tree rat...






























Go page eagernoskills and ovenpaaa: we need their input.

[Sim G]

While they are on they could also figure out why my 45ACP cases get shorter with firing.

I have never had to trim my 7mm-08 either. Some of them have been fired 8 to 10 times. Only ever neck sized and never loaded to the maximum.

[Sim G]

Slightly off on a tangent, or perhaps not, we once had a 7.92x57 case that had a split in it after ejection. It was a milsurp round, one from a batch of 400, and the only one to show a problem. The split was about 3 mm long and halfway down the cartridge. We didn't notice anything unusual on firing, no inaccuracy, no odd sound, no venting of gas. We didn't know anything about it until clearing up the fired brass and finding the split case. The round was from 1953, the rifle a K98. We've seen nothing similar, before or since.

Worthy of investigation ? Related in any way to our question ?

One case of sub standard manufacture. Considering the amount made, it's hardly surprising that some may slip through the net...

[dromia]

While they are on they could also figure out why my 45ACP cases get shorter with firing.

Do they?

What evidence do you have?

Is it all cases, or just some?

In what gun ?

*curious*

Evidence?

Loading and shooting hundreds of thousands of rounds over the years in sundry pistols mainly of the 1911 variety, also Armalon Pistol Calibre No4 action conversions and no doubt other sundry firearms that I have long since forgotten about having and or using.

Institutional and cultural lack of trust is the bane of our lives eroding the values by how we try and live.

[meles meles]

Institutional and cultural lack of trust is the bane of our lives eroding the values by how we try and live.

We hope you didn't feel we were impugning your integrity, ooman: we don't doubt you at all ! However, if we are going to deploy a fine mind and multiple resources upon such a project, aforesaid fine mind will require evidence to which it can apply The Scientific Method. By "what evidence do you have" we meant did you simply observe one day that the cartridge was a tad short, or did you go further, measure them with a calibrated stick, make notes, save a few, compare different brands, the effects of different loads and so forth. Quantifiable data are what we seek...

It seems to us that not all cartridges behave alike, and small variations can have big effects upon performance. It would be nice to conduct a proper study into it... A while ago we had a look at if, how and why eagernoskills' 'ocerous brew worked, and found that it attacked copper fouling by a process of preferential inter-granular corrosion rather than simply dissolving it away uniformly, thus establishing a reason behind the general observation that 'it is good stuff'.

[dromia]

I know C2R is good stuff, don't need no stinkin scientifik meffod to tell me that.

Even when it does I an still none the wiser other than what I already know that it is good stuff. Damn academia I say and all the back p!ssers that populate it.

Evidence came from measurement of the cases during the case prep stage, to ascertain the shortest case length in order to trim to that.

Methinks it would be wise to have an experienced handloader on hand to help your fine minds with the real world context that their scientifik meffod should sit in.

[Maggot]

I heard G David Tubb suggesting that polished cases had less stiction between the chamber and the case and therefore caused more bolt thrust....who knows.

Probably cant be arsed tumbling the things (I don't bother either).

But then would that cause the cases to stretch more? Poor headspacing wont help.

The worst splits and neck separations...and base separations for that matter I have seen were all on .303 brit or straight, thinner walled cases.

OK, .303 brit was designed for BP and is probably an unfair comparison.

I wonder if the abrupt neck angles (particularly on some of the larger capacity magnum cartridges and wildcat derivatives) on some of the more modern cartridges arrests or enhances stretch.

Would a less steep step enhance or reduce stretch....or have sod all effect on the hell and corruption going on in the case?

Some serious research on flash holes might not go amiss too as regards consistency. Do they have an optimum size for all primer/powder combis, or would modifying a flash hole (tuning it if you like) to a powder/primer combi help?

Would there be a formula....no idea but its a thought.

And finally and most important....why do I always produce my best shooting when it don't matter zzzzom

Take care

C

[Maggot]

Here's another thought re case neck turning.

I don't bother, I don't need to in order to chamber my stuff, and I don't then fancy having to either re-set a bush for every batch (or keep die and bush combos set up for different batches).

But I have the ability should I need to....I might even sort my nest long range lot by concentricity/thickness etc, not sure.

Depending on how much is needed I might even true some up with the trimmer but.

Thing is, if a case is not uniform in wall thickness, and is effectively being extruded (albeit by being slapped against the chamber walls like a pitta in a tandoori oven) would there not come a point where the neck brass was replaced and the turned portion removed by trimming...or

As a well known shot pointed out...

"Why bother worrying about concentric necks....one firing and its formed to the chamber/throat anyway"

Thoughts?