Yes, but the rifling will spread out your pattern more than you want.
1 in 10 IIRC
1- 12 twist
Remington .270, 150 grain.
.308
The twist on the inside of a gun-barrel is called rifling. I dont know the specific pitch of the rifling in this particular gun but thought you would like to know the proper terminology.
Standard
Type of rifling/twist.
shot gun and very early muskets
That would depend on the caliber of the particular Remington Model XP-100 you have. Remington chambered these hand-guns in a multitude of calibers from .221 Fireball and up to the .350 Remington Magnum, so rifling twists will be different from one caliber to the next and the specific twist in that barrel will play a big role in how accurate a bullet performs.
Usualy a Remington 870, sometimes a Mossberg 500 or a Benelli
depending on condition of the wood and the finish on the steel, as well as the rifling in the barrel and the action of the bolt... your price could range between $250-$450