The 327 Federal Magnum would not be my first choice, but the ammo, brass and bullets are out there. You can shoot the 32 H&R Magnum & 32 S&W Long cartridges, plus all can be reloaded with the same dies.
The 338 Federal is an awesome cartridge and will live along time, since it is made from the 308 Winchester parent case.
I also like the 338-06 A-Square, but there needs to be more rifles built for it, also will live on since its based on the 30-06 Springfield parent case.
The cartridges I don’t believe will live long are as follows:
The (WSM) Winchester Short Magnum are probably going to keep the best running rate, but the (WSSM) Winchester Super Short Magnums will die off.
So far we are pretty much in agreement.
The .325 Federal is a good cartridge and may hang on but I don’t think it will ever be a spectacular success. The .338 Federal is a great little cartridge that deserves to survive. Lots of the “right stuff without a lot of recoil. Ditto the .338-06 A-Square.
The .300 WSM looks like a survivor but I doubt the other WSMs or RSAUMs are long for this world. That applies double to the WSSMs.
375 Ruger, will never replace the 375 H&H Magnum.
300 and 338 Ruger Compact Magnums (RCM) These are crazy.
Have to disagree here. The .375 Ruger offers .375 H&H performance in a standard .30-06 length action. Higher volumes on the actions mean lower manufacturing costs which should translate to lower costs to the consumer. The .375 Ruger case is also a great case for developing additional magnum-performance cartridges sans the “magnum” belt. It maximizes case capacity for a lot of rifles without sacrificing magazine capacity.
The .300 and .338 RCMs are fine short action cartridges, without the stigma of or complications arising from the of the Rick Jamison WSM lawsuit. That said, I would have preferred to see the .338 on a full length .375 Ruger case.
(RUMS) Remington Ultra Magnum, to include the (SAUM) Remington Short Ultra Magnum. I feel these are either too large or too small.
The .338 RUM is here to stay, but it is too long for many .30-06 length actions (and intentionally so, I believe, which is one reason I favor the .375 Ruger case).
I am sure I am missing some, but so feel free to add to the list.
I am so glad all my rifle cartridges are based off the 308 Winchester or 30-06 Springfield parent cases, I don’t have the worry on finding brass.
Oh I do have a 223 Remington and 30-30 Winchester, but that brass is easy to find as well.
Two more that I think deserve to survive include the .308 Marlin Express and the .338 Marlin. For levergun lovers (like myself) these are wonderful cartridges. I think the .338 has a better chance but suspect neither will ever gain a large following.
Brass is never really an issue with me. Once I buy a rifle a lifetime supply of brass, generally 5000 cases, generally follows shortly thereafter – even with my .30-06s and .308 Win.