My cousin is pondering a Uberti 1873 carbine levergun in 44 mag, how heavy of a load will they take? The twist I guess is 1-16 or something like that, enough that it should stabilize heavier bullets alright. He isn't looking to feed it a steady diet of heavies but he wants to know where the roof is for this rifle should he feel the need.

the toggle link is stronger than the old myths and urban legends of he past would have you believe, but i would stick with 240 and 250 gr loads, loaded to factory specs
maybe an occasional [ for hunting ] 265 gr load

He should get inside an 1873 and take a look at how it locks up. It is NOT an 1892 by any stretch of the imagination. With modern steel and such it's likely stronger than the originals, but it's still a toggle link. If he wants to hotrod it he'd be better off picking up a '92 instead. They are a fascinating reproduction, but they are still the old toggle link at heart - not designed for high pressure modern loads.

I have heard of the early ones having a problem with the receiver stretching. I would google it and read what has been written . J.Michael

YOUR brother is looking at this wrong, Bill. That rifle will take standard factory 44MAG loads from 1300-1400 and goose 'em up to 1800 strictly from the longer BBl on the gun. This alone produces about 70% more muzzle energy. There is no substitue for velocity not for barrel length to get it. Also , when you noted the word 'heavies' do not know if you can get 'em in the gun as the '73 takes a cartridge LOa of 1.590" MAX on everything else and I suspect that includes the 44MAG cartridge.
That rifle was proofed with to CIP specs and they tend to be a bit higher than our SAAMI specifications, but for dangsure I would NEVER push it past that.

I've taken my '73 in 45LC apart so many times I could do it in my sleep. It does use modern steel, but I don't care for how it locks up. This is why its so darn fast in CAS cause it don't have all that twisting of lugs to worry about. I certainly would not push it and not only that wouldn't even use factory 44Mag ammo in it either. Just my opinion. Just get a '94 30/30 and use the '73 for fun stuff.

If I had one I would be glad just to load a 200 grain RNFP like I do in my 66 only instead of 1200 with the 66. A steel 73 chambered in 44 mag I would have my load doing about 1500 or so and think of it as a souped up 44-40 and be glad.

Bob

Like I said my cousin is thinking about this seriously but just wanted to know how strong it really is. I cant think of what it would kill with a 330gr bullet at 1400fps that wouldn't die just fine to a 250gr bullet at the same speed.

Thanks guys