Converting a 32 Rimfire Rifle to 32-20 (32 WCF)

   01.31.19

Converting a 32 Rimfire Rifle to 32-20 (32 WCF)

Leave it to Larry Potterfield to distill a gunsmithing process that’s not exactly easy — in this case, converting a .32-cal rimfire rifle to accept and fire 32-20, a.k.a. 32 WCF (Winchester Center Fire) — down to less than seven minutes of video.

Larry explains why the old Remington rolling block rifle is a good candidate for the process… it’s been modified in ways that diminish its collector value, so it’s more useful as a shooter than a wall-hanger. Rimfire ammo in .32 caliber is scarce and costly, so it makes sense to convert the rifle to use a centerfire round which is 1) readily available as new ammo and 2) easy to reload.

Then he gets busy cutting a new chamber. The 32-20 is longer and larger than the 32 RF, so once the new chamber is formed there will be no trace of the old remaining. This is a good thing. Both rounds use the same bore diameter, so the rifling ought to work just fine with the 32-20.

Once the chamber is cut, the off-center rimfire firing pin is removed from the breech block, and the hole is drilled, tapped, and plugged with a screw, which is then worked down until it’s flush with the face of the breech block. Of course, care must be taken not to remove material from the breech block face during this process.

The breech block is drilled for the new firing pin, which is homemade on a lathe, fitted, and notched so it can be retained in the breech block just as the old firing pin was.

After reassembly, the rifle is taken to the range and fired. Although I would have preferred to have seen him proof the gun first, by remotely firing an overpowered 32-20 “proof load” cartridge in a safe environment to ensure it’s strong enough to handle standard-pressure 32-20 shells.

Pretty cool project!

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