I have a in the white 1915 variant Stevens Favorite action.
I'm thinking of making a set of switch barrels for it. One
Would be 22lr and the other barrel 22 wmr. Does anybody
think these actions aren't strong enough for the 22 wmr?

SAAMI lists both the 22 LR and 22 WMR as having the same Max Pressure.

I have two new extractors just maybe I can regulate one to accommodate both rounds.

Been there done that it works fine with one extractor. But the reality is I don't use the 22LR barrel at all.

I have done 22LR and 32-20 with the same breech block! You do need 2 extractors though. This is a more versatile 2 barrel set.

Regarding action strength, Ackley showed that a straightish wall ctg (such as his AI versions) with a solid head generates almost no backthrust. Based on this, I have done a Favorite in 256 Whoops (improved version of the win mag). Having said that, replace all the pins and screws, and particularly the lever screw, with replacements made from drill rod (correctly hardened and tempered). The originals are soft and wear easily, leading to a sloppy lever.

Thank for that info. Now off to the races!

Is thrigger for the 1915 model the same as the 1894 model? I need to replace my 1915 trigger.

see wisner's site for info on the variants of the favorite. The mainspring on the 1915 is a coil mainspring, the earlier versions had a flat spring. So the hammers are probably not the same. I don't recall regarding the triggers.

Thanks Russ.

Look at the latest models on that single shot and make a new firing pin to protect the gas from getting into your eyes. That was a real problem with old models and Knight's Gun Shop wouldn't allow us to make firing pins for these guns.

If you could find a 44 or 44 1/2 model you would have a reasonable rifle to convert.

Just my 2 cents worth

If you have a blowout with the 1898 or 1915 in rimfire, it will scare the crap out of you but the gas vents up and down depending on where the rim ruptures. This happens if the breech block is loose. Had that happen once. Cure is to replace worn pins and screws, you might go up a tad in diameter if the holes in the action pieces are worn. There is an outfit called Palmer something that supplies hardened pins of the right length, and a tad oversize. Or you can use drill rod and harden/temper that. For screws, if you want bullet proof screws you have to make them from drill rod as the commercially available ones are softish. (Cedar Creek Machine makes them but they are just mild steel.) If you don't have a lathe, you can buy a grade 8 bolt (aircraft grade), chuck it in a drill, and grind down the head on a wheel. I forget the size but there is a size that works, again it's a bit oversized so you may need to do some drilling and tapping but you don't need a lathe for that. Once it's done it's never going to bend, ever.

On a centerfire conversion, I suppose gas could escape via the firing pin bore but the hammer will be in the way. The most likely cause is a fp that is too long. You have to make a new fp anyway so make it tight and right.

44 has the same fp/breech block design, just scaled up, so same potential issues.

The 1915 is plenty of action for any rimfire conversion.

44 1/2 are valuable rifles these days, best kept original.

The trickiest part of any conversion is the breech block. 22 will work for 22 mag and HMR. 25RF will work for 5mm RF mag. CF you have to d&t the fp hole to plug it, and then carefully redrill, and you really need a mill to do it precisely.