Or, putting it another way, shooting the  Pope 308403 for the 1st time in my 30-20 was a success...
Bear in mind thqt the bullet is almost as long as the case itself, and weighs in at 165+ grains - still stability calculations showed that my 1:15" twist barrel should stabilize this bullet.  So, I lubed up some bullets, charged some cases with 16.7grs of Swiss 1 1/2Fg with a cork wad to keep the powder in and went to the range...
The rifle was my trusty and lightweight BSA 12/15 rebarreled to .30-20 and equipped with aperture sights.  The little rifle weighs about 6 pounds, and has a very nice trigger indeed - not a set trigger, but very crisp and dry at around 2 pounds.
Loading procedure was extremely simple - but also something I was a bit afraid of beforehand , as I was worrying that the 16:1 cast bullets would give trouble seating.  I made up a plugged case - which turned out to be completely unnecessary,  BTW.

Basically, I pushed the bullet in the chamber, followed by the case which seated the bullet into the rifling (at least, that's what I presume - it all went pretty easily) with just a smidgen of resistance.  Kinda like pseudo-breechseating I presume, except the rear of the bullet would have been -barely- in the case.
After firing, I started out by wiping with 2 humid patches (oil/water mixture), but for the last 4 shots I followed this with an extra dry patch.
Results? about 2.5 MOA shooting prone, with sling, no rest, nicely centered, with only 1 shot outside the 10-ring of the 25m ISSF-target.
The last 4 shots (with the dry patch) seemed to be just a bit more accurate, so the cleaning routine needs some more experimenting...
But the combo does seem to be a winner indeed - if I can get this already from the 1st try, things are definitely looking good.  That Pope bullet definitely is a winner.