I see X-Treme has a 220 bullet. All the load data I have found only goes up to 200 ? Does anyone have any experience with this load. I like the bullet because I hunt hogs here in Fl. with My Delta Elite. And from experience big boars laugh at hollow points. lol
Here is my take on the 220, loading I have pulled down from Underwood and Double Tap are listed in the 10mm "Pull-Downs".
Seeing that you are using the Delta Elite, you may want to try the Double Tap loading of 7.2 grains of LongShot see here; http://10mm-firearms.com/factory-10mm-ammo-pull-downs/double-tap-230gr-hard-cast-pull-dowm/ (http://10mm-firearms.com/factory-10mm-ammo-pull-downs/double-tap-230gr-hard-cast-pull-dowm/)
The Newer Underwood was reduced but may still give "smiled" as shot from the DE's with a lack of case support at the feed ramp.
If you want to compare the Underwood loads for your consideration look at this "pull-down" and be sure to look at post #9 where the load was reduced...http://10mm-firearms.com/factory-10mm-ammo-pull-downs/underwood-220gr-hard-cast-pull-down/ (http://10mm-firearms.com/factory-10mm-ammo-pull-downs/underwood-220gr-hard-cast-pull-down/)
Good luck with your decision! 8)