Can a Stevens 25 RF be converted to 25-20 WCF?

[Chev. William]

vh2n,

very Good report of your experiences, thank you for sharing.

Best Regards,
Chev. William

[NoZombies]

Well at the risk of being excoriated I am going to state the following:

1. The 22 mag is loaded to the same pressure (SAAMI) as the 22 lr. I have a Stevens 1915 that I fitted with a 22 mag barrel, and I have put hundreds of rounds through it. I believe I used a 224 groove barrel for the magnum but I don't remember exactly. The 22 mag bullet is .224" whereas the 22 lr is .223" so not a good idea to simply rechamber a 22LR.
2. I have converted the 1915 to CF in the following calibers: 218 Bee (40,000 psi), 256 Win Mag (43,000 psi), 357 Magnum (35,000 psi), 32-20 (16,000 psi)
3. I have converted an 1894 from 32RF to 32-20
4. I have fitted a ruger 10/22 barrel to a favorite.

In all cases I replaced the action pins with modern hard pins that were a hair oversized, calling for reaming prior to conversion for a tight fit. I have replaced the action screws with modern steel screws made from grade 8 bolts, or alternatively from drill rod that was hardened after turning. I usually make the lever screw (and this is the weak point as the screw is skinny) one letter size larger than original as the holes in the lever and the action are usually a little oval so I ream them round to take the new screw. If I cut threads I make them as shallow as I can. The action must be made tight and over center before setting up the headspace for any of these conversions.

In some cases I have threaded the action and barrel shank, but in most I have used the standard retaining screw.

I have casehardened some but not all of the actions. As someone stated these are cast steel not cast iron. But not as strong as forged steel. When you engrave one of these actions, you don't get nice curls, you get chips.

In all the CF conversions, I use mild handloads and I make sure there is adequate leade in the throat.

The only problem I have encountered is the lever screw bending, and that was using modern replacement screws that I bought from a vendor. After that I made my own oversized and hardened screws and had no further problems. I find it difficult to imagine that the breech block can fly out of the action as it is attached to the lever assy as well as the action itself. If it failed it would likely "gape" allowing hot gas to escape from the primer and/or cartridge head, most of which would be deflected upwards. I had this happen once with a 22lr that was a bit loose but unmodified. The case failed at the rim, there was a rather loud bang and some smoke but no harm done.

The breech block is buttressed by the action shoulders which I believe adds a degree of safety to the action. If the action starts to yield the play will be obvious, which is not true with other types of action where the lockup is not "tactile" and exposed.

I do recall reading in a book by P.O. Ackley where he did an experiment on a rifle that was chambered for 30-30. He successively and deliberately increased the headspace and was unable to detect any breech thrust at all due to the brass gripping the chamber walls. If the CF case is roughly straight-walled, it seems that theoretical breech thrust is not reached in practice. It should be relatively simple to calculate how much pressure a given brass case can withstand before it needs to rely on the breech block to prevent failure in tension. I suspect the ctg manufacturers dimension the case accordingly but I am not sure of that. No rimfire cartridge is going to display this behaviour as the cases are very thin indeed. That's why rimfire ctgs are loaded to low pressures. And sloping cases (like the hornet and the infamous 22 jet) are not going to grip the chamber as well as straighter cases like the 357 Mag.

I have also converted a 44 in 25RF to 5mm Rem Mag. The firing pin on a 25 Stevens does not need to be repositioned for this conversion. The 5mm has MUCH higher pressure (33,000) than the 22 lr or WRM (25,000) so you have to have a tight extractor fit to support the thin case rim. The Remington 592s had a very sophisticated two stage extractor to deal with this risk. I plan to do the same conversion on a 1915 but I would not try it on a 1894.

I would not do this type of conversion for a third party, for obvious reasons. And I should say "do not try this at home", if you do it's "AT YOUR OWN RISK".

I think the disclaimer of "Don't try this at home" should be the first, last, and only things said about this post.