Prepping Brass In Advance

[Canadian Bushman]

Just curious Canadian Bushman, was the last sizing action on the necks downsizing, or expansion? How much downsizing?

Downsizing, and nearly .008" if i recall. It was win brass and had 6-7 firings on it with no anneals. Im certain that wasnt doing me any favors.

 

[climb-101]

Maybe I shouldn't have said 'best ammo', as it's totally possible for ammo with a particular barrel & load to shoot better after it's aged. My contention is that there can be changes, and they could change results. These results would of course need to be validated.

We know there is nothing wrong with fresh ammo, as we load develop with it fresh, and anyone competitive is using it fresh.
I see sized/primed, but unloaded cases drift over time. I've seen many posts over the years with concerns about observed performance changes with aged ammo (>3mos old). And I've seen published reports of ammo creeping in dimensions over time.

I have not personally tested aged ammo -vs- fresh ammo.
It would difficult to prove scientifically, as it would take a long time to do so, and we don't currently have a way to measure neck tension itself. I could test using seating force measure, H20 capacity measurements, and a good chrono and targets, but again, it would take a long time to 'prove' one way or another.

is it possable to check the necks with a set of machinist pin gauges and see if one size fits and snug and then check it in a month or two and see if it still fits. kind of like a go/no go gauge.

also does temp have any affect on the neck tension, say its 80 deg when you load the round and it 10 deg when you shoot it, does the different rate of contraction between the bullet and the brass casing change the neck tension?

 

[Mikecr]

is it possable to check the necks with a set of machinist pin gauges and see if one size fits and snug and then check it in a month or two and see if it still fits. kind of like a go/no go gauge.

I know that the sized/unseated necks will change over time, that's a given. Tension is another matter harder to prove.

also does temp have any affect on the neck tension, say its 80 deg when you load the round and it 10 deg when you shoot it, does the different rate of contraction between the bullet and the brass casing change the neck tension?

Assuming you're referring to storage temps, I have no idea on this one. I don't store loaded ammo for bolt actions for long, and never outside of ~70degs +/- a couple.