O'Conner cases

[wildcat westerner]

Hello,

When reorganizing my reloading components recently I came across some unique cartridge cases. Oringinally they were brass straight cylindrical cases and could be formed to a wide amount of cartridges from the basic 30-06. These had been formed to .270 and the unique feature they had was that the brass was threaded at the base and stainless steel bases were threaded to them. I do not have a lot of them but, obviously engineered as they are, they could probably withstand some enormous pressures with those stainless steel bases.

I have a .280 Remington these would work with after I modified them and logic dictates, lacking information, that they could probably be loaded to 7mm magnum ballistics. Has anyone ever used these cartridge cases?

Thank you in advance for any experienced replies.

Gene S.

 

[rscott5028]

Sounds like more of a novelty/collectors' item...
Cartridge of the Month

If you need a 7RM, buy/build a 7RM.

-- richard

 

[wildcat westerner]

Hello,

Since I used to be a cartridge collector, these cases' uniqueness is not lost on me. I have also built several rifles over the years including a 7mm magnum, the need to build another one to gain the small advantage it has, compared to a strong loading of a .280 or 280 AI is not a need here.

However if someone has had experience with these cases which is near to the information I have received today, apparently these stainless steel based cases can tolerate immense loadings and also last several reloadings while doing so. I should think that anytime you can duplicate velocities with equal weight bullets and do it with 15 grains less powder, that is some pretty impressive ballistics.
Gene S.

 

[rscott5028]

Good luck with that. It appears they aren't in business any more and it's not because it was top secret stuff.

This is pure speculation, but it appears from the photos that the threaded shank cuts into your useable case capacity. So, you're going to have less capacity and more containment.

Perhaps someone with Quick Load could tell us what occurs when that happens?

My guess is that the cartridge is less efficient and results in higher pressures to achieve the same velocity. Something like Ackley Unimproved.

But, that's just speculation. I'd be curious to hear from the experts.

If you try them, start low and work up. You might even measure water weght case capacity of a once fired case and get someone to run some Quick Load data to see how that compares to standard ammo.

There's no free lunch.

-- richard