7 Remington Magnum's are too inconsistent.
Reloder28, not sure I understand what you meant by they are inconsistent? Could you maybe expand on this?
Thanks
Pieter
Don't want to be critical. I have owned several 7 RM's over the years, worked up loads for friends 7 RM's & talked to several people who have also found the same issues with them. They show a tendency to exhibit sporadic pressure variances. That equals inconsistency to me. For years they may shoot fine & then one day they don't. The last one I had I could not even get past the load work-up stage before it started.
David Tubbs, has also spoken about this cartridge citing the same observation.
Meanwhile, here is an excerpt from a 2003 24CF thread from
Mule Deer:
Perhaps a more accurate term would be "wide pressure swings" rather than spikes. It seemingly occurs with about every hunting weight bullet in the 7mm Remington Magnum.
In general, the labs expect maximum pressure swings of 2000-5000 psi with most cartridges, but of course look for the lower as a sign of a consistent load. It's pretty easy to find this sort of spread in most cartridges.
But the 7mm Remington Magnum will swing 8000 or even 10000, and often after several identical rounds have stayed within 4000 psi of each other. And oddly enough, the 7mm STW, which has the identical shoulder angle and short neck, doesn't show the same swings! This indicates that the shoulder angle/short neck theory probably isn't correct.
The problems with the .243 don't show up as much until the throat becomes a little worn--and again, only with bullets in the 100-grain weighr range. Once again, they don't know why.
Despite all this, the 7mm Remington Magnum and .243 Winchester have reputations as accurate cartridges, at least among hunters. I have used both a lot with excellent results. But nobody picks them as target rounds, and the erratic pressure swings are one reason. Oddly enough, if you neck either case up a little, to .30 from 7mm in the case of the magnum, and from 6mm to 6.5mm in the case of the .243, the problem goes away. Why? Nobody knows.
_________________________
John 
