Factory ammo doesn't always come in the weight and velocity I want for competition, so reloading just the path I go. Never mind that when competing, 300rds for a two day match is much palatable to load for, rather than buy (cost wise), and with bulk components, the "lot" is always the same. A lot of guys buy 3000 bullets when they buy their replacement barrels, specifically for that reason; no waste in barrel life re-zeroing with each new lot of ammo.
As far as cases staying in the pocket, magazine or plastic boxes; yeah, that doesn't happen in competition, with par time 12 rd stages. Especially when they're as short 1:45 to get in position, on target and get off 12rds at up to 5 or 6 different targets/ranges. Not to mention the differences between an rather anemic rimed cartridge, compared to a modern, high pressure bottle neck cartridge.
Finally, as to the Mercedes (my twin brother has that exact same car BTW) on Supermarket gas...well, your car, your decision. Doesn't make it the wisest one, but definitely your decision.
My wife's Toyota gets cheap supermarket low grade gas; it doesn't warrant (or need) it. But my other two vehicles are both four cylinder, direct inject turbos, and there's no way I'd be foolish enough to run mid or low grade fuel in them. That's just not what they were designed to run on.
