Which rifle?
If you are referring to the Marlin Levermatic conversion, it is already done by Marlin (for a Model 62) in CF caliber (I bought a 'surplus' Model 62 .256 Win. Mag. Bolt assembly from Numerich Arms and my gunsmith welded and machined the Bolt Face to fit a .25ACP rim). The Extractors (left and Right) are coil spring loaded 'levers' so they easily closed to pick up the new rim size.
If you mean the "modified' Stevens 1915 Favorite Action/Rifle; I bought spare reproduction Extractors Blanks (similar to a 1894 Favorite center line type) of constant width, then had my gunsmith machine the tips to fit each of four different Cartridges: .22LR, .25ACP, .25 Stevens, and .32 Long/.32 Long Colt. I now have them stamped as to cartridge the fit and have stamped them with the Action Serial number as the Pivots in this 'Modified' Action are larger than normal. The Breech Block is still set up for ".22RF" Firing Pin tip position so the other sizes will need to be adapter cases using .22RF blanks centered in the adapter for Ignition.
Perhaps later I will have the Breech Block and Firing Pin modified to allow change over between RF and CF tip positions.
I found on "Ebay" some 1915 Reproduction ".22LR" breech blocks CNC machined from 4140 Alloy Steel for a good ($28.00) price so I bought two and had my gunsmith convert them to CF and weld two "pads on the Rear edges so they could be 'dressed off' to tightly fit against the rear side 'shoulders' of the 1915 Stevens Favorite Action.
Due to other commitments, I did not get to the Range this Thursday to test fire the Favorite, so I changed out the .25ACP Extractor for the .25 Stevens Extractor, temporarily mounted an old Lyman Tang rear sight on it, and cleaned and oiled the bore again. This Stevens ".25 Stevens" barrel is somewhat pitted on the inside but has good visible remaining Rifling from end to end and has had the Crown 'touched up' to be a 'Recessed Target' type to reduce the chance fo future Crown damage in handling.
This barrel and Action is mostly 'in the White' at the moment with the signs of past handling dings still visible on the barrel especially.
The Front sight currently on the barrel is a 'German Silver Reproduction 'Western' style Blade that tapers from low front to high rear over about a 3/4 inch length.
The Rear, Tang, Sight has two sizes of Peep holes built in , with the small hole able to be 'flipped' out of the way of the larger one. It may be too tall for close work as at it's lowest height the sight line is well above that of the old single range notch sight most of my old Stevens Barrels had on them, even with the unmodified Front sight blade.
Other 'putter projects' this week: Get three Micrometers 'unstuck' and working again, including a 0-1" range .0001" measuring "blade" type for measuring narrow groove diameters, I was successful and they are now working for me.
One of the other two, also a .0001" reading 0-1" range is missing the fixed anvil so I will need to see about getting it professionally repaired.
The third one one is also a .0001" reading 0-1" range standard Brown & Sharp model 13 that is now usable but still has some corrosion 'pitting' on the "C".
This has been a productive week for my projects and I have improved my accurate measurement capabilities quite a bit. Before I was limited to a 'Dial Caliper' that has some 'sticking' problems that I have not yet been able to straighten out.
Best Regards,
Chev. William