Getting a magnum cartridge and "loading it down" makes as much sense as getting a Shelby GT and putting a governor on it.
............I'll disagree! That is what reloading does and what it is for. Load up or load down to suit. And there was no mention by me, that if one owns magnums, that reduced loads should be used 100% of the time. Because if that were the case, only then it wouldn't make any sense to own a magnum...
And btw, I own a 2011 Shelby GT500 convertible. It is speed limited from the factory at 155. Well below its top end potential if it were not electronically speed limited. And yet, I have not gone over 100 mph with it.
More fun from 0 to 70-80......
