Ribbonstone is right, but there is a timing issue. The full fluted Army (or Navy) cylinder has the locking notches essentially on top of a fairly steep hill, meaning that if the bolt drops early, the nose has to climb that slope to get to the notch, and this is all loading up the pressure on the hand as you try to cock the gun.
I found (the hard way) that timing a full fluted cylinder can be a real chore. The bolt MUST drop into the notch's lead cut at the earliest so that the ramp isn't encountered. This, if you have an early dropping bolt to start with (which probably scraped a line on your round cylinder), you will most likely have to start with a brand new bolt, so you can adjust the drop point off the hammer's cam, and make sure your hammer's bolt cam is clean and sharp as well.
Once the fluted cylinder is timed in, the round cylinder will be perfect. If the bolt drops a bit late or dead into the notch, you run a chance of skipping if you cock too fast, so the proper timing window is narrower than with the round cylinder.
Not to scare you off, because the gun is really beautiful with that cylinder installed, and worth the effort to get it running right.
The critical timing issue, I'm sure, is the reason the Single Action Army cylinders (and most all other modern cylinders) are only half fluted.