I've come to the conclusion that Travis was shot with a jacketed, hollow-point bullet.
The slug recovered from his skull was manufactured by Winchester and weighed exactly 44.8 grains.
Winchester full metal jackets only come in weights of 50 grains or greater. Hollow-Points, however, are never greater than 45 grains.
The slug was in pretty good condition (just a bit flattened) and the ME reported finding no traces of metal fragments in his cranium. I also looked at other damaged bullets that retained their original weight (one guy did an experiment on this and posted pictures and information on his findings) and many looked far more mangled than the one that struck Travis. The worst looked very fragmented (it had also mushroomed considerably), yet it only lost 1/2 grain of weight. So I'm convinced that based on the above, the bullet recovered from his skull retained nearly all its weight and this weight would make it a Winchester 25 auto "expanding point". In other words, a jacketed hollow point.
It solves a mystery too. Like how a 25 caliber bullet managed to pierce his skull from a distance of two-feet or greater. The 25 hollow-point, thanks to its lesser weight, has a significantly greater velocity than a FMJ (815 ft/s vs 760 ft/s), providing it with a force necessary to impact the brain (though not enough velocity to cause expansion).
However, I'm not convinced that this slug was one of the 7 hollow-points stolen from her grandfather. If she had any sense at all, she would have test fired the gun. It would have been utterly foolish to fire the gun for the first time during the murder. That wouldn't happen. She must have test fired it and likely more than once to get the hang of it. Then she would have wanted to replace the spent ammo so that she would have a full clip just in case. This means that she must have purchased extra ammo somewhere. Unfortunately, there were no laws that regulated handgun ammunition sales in 2008. The bill signed in 2009 by Schwarzenegger (requiring a fingerprint and ID to buy ammunition) was struck down in 2011 just before it was supposed to go in effect. So don't expect a "smoking gun" regarding an ammunition receipt.