I put together a 600 for smaller folk a couple of decades ago, closer to 3 actually. I used a Brown Precision in Kevlar. They still list this available on their site. It's qualified with a comment about using a 700 trigger guard. I don't remember any particular difficulty getting it to work.
Mine is in a 6mm Remington, and I don't see a reason the 260 won't work, unless you require a longer action for seating bullets out longer.