Charlie Bell RPG Superstar 2015 Top 16, RPG Superstar 2013 Top 16 |
Short answer is no, and add pluses.
In the spell description of permanency, there's a short list of spells that can be made permanent. Spells from later sources that can be made permanent usually say so in the spell description and list the cost.
You can always add pluses of enhancement bonus or weapon qualities such as flaming, frost, shock, holy, etc. to a crossbow to increase damage. You can somewhat stack these by putting enhancement bonuses on the crossbow, and using, for instance, +1 flaming bolts. The enhancement bonuses won't stack, but you will get the extra fire damage on top of whatever pluses you have on the crossbow itself.
If you have gravity bow on your spell list, you can buy a wand of gravity bow for only 750 gp. 50 charges that last a minute each will last you through many adventures before you need a new one. You can do the same thing if you have a decent Use Magic Device skill.