"The bargain is in the buy."
If the deal is good, the details will work themselves out.
Part of that is that you really aren't looking that hard for that .123grabazoid ammo until you buy that Gretzky SuprSlamr. Afterwards, you will really start to pick out those boxes.
Want to really notice all that 9x23win? Buy an arm that uses it. You'll be pawing in that pile next to the .38super and .38acp . . .
Now, in all fairness, my perspective is from a moderately full safe, too. Ok, I might reconsider something in 8mm nambu or .32 french longue--maybe. But, those are hard calibers to find in times of largesse.
Would I buy an Astra in 9mm largo? It would bear some thought, but it would fall on what the selling price was. A .276pedersen? Sure, even with nearly unobtanium ammo. Price comes back to the front. Somebody offers me a .276 Pedersen toggle lock for under a grand, it's getting the microscope treatment, but, I'm not passing on it without a great good reason. Five grand, maybe not so much.