Rebel, I have mixed Coil Spring Barrels and Flat spring barrels with only one problem. If you use a Coil Spring barrel on some
there is no place on the Barrel to mount the Base for the Flat Spring. If you use a flat spring barrel on a coil Spring barrel all is well. You just have an un used Dove Tail slot under the Forend. I have successfully put a Rifle together with both the Flat Spring and the Coil Spring on the Hammer. Very stiff. You almost have to use the Lever to Cock the Rifle, it can be thumbed back but is very stiff with both springs in use. By the way in only two instances over 50 years have I found original Winchester Barrels to not pull up correctly to a good condition Hi Wall. And those two had been reworked in some manner by a smith in the action threads. May have been an effort to Blueprint the actions as some Race Car Engine builders did.
HTH Regards, FITZ-G
By the way that system was very hard on Hammers that had been lightened up with Holes drilled through the Hammer body or the Thumb spur. They tended to break where the lightening process had been done. FITZ.

Rebel. just re read our conversation. The only comment I would or should have added was if he was looking at what was a coil spring barrel and it was for a Takedown it would look like it would not fit up in a Flat Spring action. The thread shank is longer on the Takedown by about 1/2" Not a firm number as I am working from memory here. Hope I did not send you down a dead end. But a Coil Spring Barrel for a solid Frame action has the same Thread Shank length as the Flat Spring Barrel.
Regards, FITZ-G