I've started looking around for some kind of rifle shooting the same ammo as the Mosin-Nagant. As you might know, the Mosin Nagant surplus rifles that were going for less than $100 in recent times (i.e. prior to a few weeks ago). I picked up one a few years ago for less than $100, and it's a fine shooting rifle. Later, for less cash than the first one, I got a barely used carbine model with I think an 18" barrel and lots of ammo.
The carbine is a flameshooter, indeed. It's a potent cartridge and I've heard it called "The Russian .30-06". Note that the cartridges ARE NOT interchangeable.
The big attraction is not so much the Mosin Nagant rifle part of the equation, but the fact that ammo is cheap. Way cheap. A few years ago, I almost bought, but to my current regret didn't, a semi-auto AK clone chambered in 7.62 x 54r Russian surplus sniper/battle rifle.
That's the only other kind of long gun I've seen for sale in this caliber.
You can get 440 rounds of corrosive ammo for $82 today at one online dealer, and upgrade for some more bucks to non-corrosive, with larger discounts in larger lots. There has been a ton of this ammo around for the past decade at cheap prices.
So I wish that H&R made a single shot rifle for the 7.62 x 54r caliber, and likewise a barrel for the 7.62 x 39mm. There was talk that someone was coming out with a bolt action for the 54r, but I didn't see anything yet in the SHOT reports I've read.
I've just begun to look around, but have not seen really many sporting rifles at even large dealers that come in either caliber. Which is interesting because in Europe and other places these calibers are apparently popular in some sporting weapons. It's at the cheaper tier of ammo in the U.S., and you get a lot of bang for your buck with the 54r especially.
Maybe someone has made more modern guns in the same caliber as the Mosin Nagant and I'm ignorant of them. I've seen some drillings (all of which are way out of my price range and of any hope of purchase now or in the future) in this caliber, often with 16 gauge shotgun barrel(s).
I do know Mr. Google, but it's not something I've had time to search for really. But I've looked for those calibers in sporting arms with several large volume new and used dealers and have never seen one.
AAC just came out with a rifle in conjunction with H and R, the AAC BLACKOUT HANDI-RIFLE which is in the very new caliber of .300 Blackout. What I need is a barrel each for the 7.62 x 39mm and the 7.62 x 54r on a setup like the AAC rifle. Maybe an 18" barrel, but otherwise the same. I wonder how many rounds of decent cheap ammo you can buy in the Russian calibers vs. the .300 Blackout?