Great Idea Bob.
The three CFX rifles have serial numbers on top the barrels. I am sure there are other CFX's out there which would do well with other pellets. They worked great with the RWS Superdomes so I never used a different pellet.
This is just my opinion on the pellet types which my springers love. I have other springers and PCP's that use a variety of pellets and are very accurate with most of them.
I will start with my collection of Gamo's..

1. Shadow 1000 .177 - Loves, JSB .177 DIABOLO EXACTS, 8.4gr. Have not hunted with them. Punching paper they work great.
2. Shadow 1000 .20 - Loves, BEEMAN / MARKSMAN FIELD TARGET SPECIAL, 11.5gr. Great for punching paper.
3. Black Shadow Supreme .22 - Loves RWS Superdomes, 14.5 gr. Good for paper punching and hunting. Usually one shot per squirrel under 40 yards is leathal.
4. Hunter 440 .177 - Loves RWS Superdomes, 8.3 gr. Good for paper punching and hunting. One shot per squirrel under 40 yards is leathal.
5. Hunter 1250 Royal .22 - Loves RWS Superdomes, 14.5gr. Work great for hunting under 75 yards. One shot one kill. Usually does not matter where you hit the squirrel. He just dies..

6. CFX Royal .177 - Loves RWS Superdomes, 8.3gr. Good for paper and geat for hunting. One shot per squirrel under 40 yards is leathal.
7. CFX Synthetic .177 - Loves RWS Superdomes, 8.3gr. Good for paper and geat for hunting. One shot per squirrel under 40 yards is leathal.
8. CFX Royal .22 - Loves RWS Superdomes, 14.5gr. Good for paper punching and great for hunting. One shot per squirrel under 40 yards is leathal.
9. Damo .... AKA Daisy 131, .177..

- Loves the RWS Superdomes. Great small springer for targets under 40 yards.
Gene