I installed the PTG and Like has been said. There is a tab that sticks out from the rear of the mag well that needs to be removed. The mag will fit just fine without ammo without out it removed, but will not allow rounds to come up to the chamber. I removed mine with a dremel tool.
Its similar to the Remington action that has the screw hole that in the rear of the mag well that needs to be removed sometimes.
It is a drop in to the stock in letting, but not the action.
I also found that to make the PTG work with my stock the bottom meal sits proud of the stock by 1/4 inch. I can not get the bottom metal to sit flush without the feed lips of the mag sitting way to high and hitting the bolt. I think its a stock issue, there is not enough material between the bottom of the action and the bottom of the stock.
Other than that, its works great.