Those IIRC...were the T3 actioned rifles. The "new and improved" T3X has a larger ejection port...which for long, mag calibers is helpful. I have both in .300 WM. Love 'em both...but enjoy a few other features on the T3X a little better.But...if you are going to put the action into a custom stock - those will not matter, and you can get a competent gunsmith to open/elongate the ejection port a little if you see the need. This may be more of an issue if you plan on seating your bullets out longer. Also - the few issues I have had has been related to the maximum cartridge length that the factory mag will run reliably. Best solution is new bottom metal, and after market mags....