There are still many manufacturers chambering the .300 Win Mag in rifles that feature short magazines, potentially (but not always), producing less than desirable and sometimes frustrating performance with hand loaded long for caliber projectiles. A minimum internal magazine length of 90mm (3.543”)...
The 9x23's Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) maximum average pressure limit is 55,000 pounds per square inch (psi), the same as a .223 Rem. rifle round! Compare that to the 9mm Luger's 35,000 psi and its +P limit of 38,500 psi. The 9x23's older cousi...
Additionally, there is also still a large quantity of full metal jacket military surplus ammo in 7.62x51mm NATO out there. This ammunition isn’t as inexpensive or easy to find as it used to be, but there are still good deals to be had if you look hard enough. Surplus FMJ ammo is ...
Since the 5.56x45mm NATO, .300 Blackout, and .308 Winchester are so popular, most of the big ammunition manufacturers produce a variety of ammo for all three cartridges. That being said, the .300 Blackout certainly lags behind the other two cartridges in terms of popularity and availability...