OP, take the bolt out of your rifle. Starting at the breech, run your cleaning rod through the barrel and out the muzzle. Screw a .284 brush on the rod and pull it into the barrel and stop. Clamp a cloths pin on the rod where it exits the action so it is touching the action and indexed straight up. Pull the rod back till the clothes pin makes one revolution and is again indexed straight up. Measure from the action to the clothes pin in inches. That is your twist.
Smokey Bear---Lone Star State.